exchangelib.folders.base API documentation

# Module `exchangelib.folders.base`

Expand source code

    import abc
    import logging
    from contextlib import suppress
    from fnmatch import fnmatch
    from operator import attrgetter

    from ..errors import (
        ErrorAccessDenied,
        ErrorCannotDeleteObject,
        ErrorCannotEmptyFolder,
        ErrorDeleteDistinguishedFolder,
        ErrorFolderNotFound,
        ErrorItemNotFound,
        ErrorRecoverableItemsAccessDenied,
        InvalidTypeError,
    )
    from ..fields import (
        CharField,
        EffectiveRightsField,
        EWSElementField,
        Field,
        FieldPath,
        IdElementField,
        IntegerField,
        InvalidField,
        PermissionSetField,
    )
    from ..items import HARD_DELETE, ITEM_CLASSES
    from ..items import SHALLOW as SHALLOW_ITEMS
    from ..items import CalendarItem, RegisterMixIn
    from ..properties import (
        DistinguishedFolderId,
        EWSMeta,
        FolderId,
        Mailbox,
        ParentFolderId,
        UserConfiguration,
        UserConfigurationName,
        UserConfigurationNameMNS,
    )
    from ..queryset import DoesNotExist, SearchableMixIn
    from ..util import TNS, is_iterable, require_id
    from ..version import EXCHANGE_2007_SP1, EXCHANGE_2010, SupportedVersionClassMixIn
    from .collections import FolderCollection, PullSubscription, PushSubscription, StreamingSubscription, SyncCompleted
    from .queryset import DEEP as DEEP_FOLDERS
    from .queryset import MISSING_FOLDER_ERRORS
    from .queryset import SHALLOW as SHALLOW_FOLDERS
    from .queryset import SingleFolderQuerySet

    log = logging.getLogger(__name__)

    DELETE_FOLDER_ERRORS = (
        ErrorAccessDenied,
        ErrorCannotDeleteObject,
        ErrorCannotEmptyFolder,
        ErrorItemNotFound,
    )

    class BaseFolder(RegisterMixIn, SearchableMixIn, SupportedVersionClassMixIn, metaclass=EWSMeta):
        """Base class for all classes that implement a folder."""

        ELEMENT_NAME = "Folder"
        NAMESPACE = TNS
        # See https://docs.microsoft.com/en-us/exchange/client-developer/web-service-reference/distinguishedfolderid
        DISTINGUISHED_FOLDER_ID = None
        # Default item type for this folder. See
        # https://docs.microsoft.com/en-us/openspecs/exchange_server_protocols/ms-oxosfld/68a85898-84fe-43c4-b166-4711c13cdd61
        CONTAINER_CLASS = None
        supported_item_models = ITEM_CLASSES  # The Item types that this folder can contain. Default is all
        # Whether this folder type is allowed with the GetFolder service
        get_folder_allowed = True
        DEFAULT_FOLDER_TRAVERSAL_DEPTH = DEEP_FOLDERS
        DEFAULT_ITEM_TRAVERSAL_DEPTH = SHALLOW_ITEMS
        LOCALIZED_NAMES = {}  # A map of (str)locale: (tuple)localized_folder_names
        ITEM_MODEL_MAP = {cls.response_tag(): cls for cls in ITEM_CLASSES}
        ID_ELEMENT_CLS = FolderId

        _id = IdElementField(field_uri="folder:FolderId", value_cls=ID_ELEMENT_CLS)
        parent_folder_id = EWSElementField(field_uri="folder:ParentFolderId", value_cls=ParentFolderId, is_read_only=True)
        folder_class = CharField(field_uri="folder:FolderClass", is_required_after_save=True)
        name = CharField(field_uri="folder:DisplayName")
        total_count = IntegerField(field_uri="folder:TotalCount", is_read_only=True)
        child_folder_count = IntegerField(field_uri="folder:ChildFolderCount", is_read_only=True)
        unread_count = IntegerField(field_uri="folder:UnreadCount", is_read_only=True)

        __slots__ = "is_distinguished", "item_sync_state", "folder_sync_state"

        # Used to register extended properties
        INSERT_AFTER_FIELD = "child_folder_count"

        def __init__(self, **kwargs):
            self.is_distinguished = kwargs.pop("is_distinguished", False)
            self.item_sync_state = kwargs.pop("item_sync_state", None)
            self.folder_sync_state = kwargs.pop("folder_sync_state", None)
            super().__init__(**kwargs)

        @property
        @abc.abstractmethod
        def account(self):
            """Return the account this folder belongs to"""

        @property
        @abc.abstractmethod
        def root(self):
            """Return the root folder this folder belongs to"""

        @property
        @abc.abstractmethod
        def parent(self):
            """Return the parent folder of this folder"""

        @property
        def is_deletable(self):
            return not self.is_distinguished

        def clean(self, version=None):
            super().clean(version=version)
            # Set a default folder class for new folders. A folder class cannot be changed after saving.
            if self.id is None and self.folder_class is None:
                self.folder_class = self.CONTAINER_CLASS

        @property
        def children(self):
            # It's dangerous to return a generator here because we may then call methods on a child that result in the
            # cache being updated while it's iterated.
            return FolderCollection(account=self.account, folders=self.root.get_children(self))

        @property
        def parts(self):
            parts = [self]
            f = self.parent
            while f:
                parts.insert(0, f)
                f = f.parent
            return parts

        @property
        def absolute(self):
            return "".join(f"/{p.name}" for p in self.parts)

        def _walk(self):
            for c in self.children:
                yield c
                yield from c.walk()

        def walk(self):
            return FolderCollection(account=self.account, folders=self._walk())

        def _glob(self, pattern):
            split_pattern = pattern.rsplit("/", 1)
            head, tail = (split_pattern[0], None) if len(split_pattern) == 1 else split_pattern
            if head == "":
                # We got an absolute path. Restart globbing at root
                yield from self.root.glob(tail or "*")
            elif head == "..":
                # Relative path with reference to parent. Restart globbing at parent
                if not self.parent:
                    raise ValueError("Already at top")
                yield from self.parent.glob(tail or "*")
            elif head == "**":
                # Match anything here or in any sub-folder at arbitrary depth
                for c in self.walk():
                    # fnmatch() may be case-sensitive depending on operating system:
                    # force a case-insensitive match since case appears not to
                    # matter for folders in Exchange
                    if fnmatch(c.name.lower(), (tail or "*").lower()):
                        yield c
            else:
                # Regular pattern
                for c in self.children:
                    # See note above on fnmatch() case-sensitivity
                    if not fnmatch(c.name.lower(), head.lower()):
                        continue
                    if tail is None:
                        yield c
                        continue
                    yield from c.glob(tail)

        def glob(self, pattern):
            return FolderCollection(account=self.account, folders=self._glob(pattern))

        def tree(self):
            """Return a string representation of the folder structure of this folder. Example:

            root
            ├── inbox
            │   └── todos
            └── archive
                ├── Last Job
                ├── exchangelib issues
                └── Mom
            """
            tree = f"{self.name}\n"
            children = list(self.children)
            for i, c in enumerate(sorted(children, key=attrgetter("name")), start=1):
                nodes = c.tree().split("\n")
                for j, node in enumerate(nodes, start=1):
                    if i != len(children) and j == 1:
                        # Not the last child, but the first node, which is the name of the child
                        tree += f"├── {node}\n"
                    elif i != len(children) and j > 1:
                        # Not the last child, and not name of child
                        tree += f"│   {node}\n"
                    elif i == len(children) and j == 1:
                        # Not the last child, but the first node, which is the name of the child
                        tree += f"└── {node}\n"
                    else:  # Last child and not name of child
                        tree += f"    {node}\n"
            return tree.strip()

        @property
        def has_distinguished_name(self):
            return self.name and self.DISTINGUISHED_FOLDER_ID and self.name.lower() == self.DISTINGUISHED_FOLDER_ID.lower()

        @classmethod
        def localized_names(cls, locale):
            # Return localized names for a specific locale. If no locale-specific names exist, return the default names,
            # if any.
            return tuple(s.lower() for s in cls.LOCALIZED_NAMES.get(locale, cls.LOCALIZED_NAMES.get(None, [])))

        @staticmethod
        def folder_cls_from_container_class(container_class):
            """Return a reasonable folder class given a container class, e.g. 'IPF.Note'. Don't iterate WELLKNOWN_FOLDERS
            because many folder classes have the same CONTAINER_CLASS.

            :param container_class:
            :return:
            """
            from .known_folders import (
                ApplicationData,
                Calendar,
                Contacts,
                ConversationSettings,
                CrawlerData,
                DlpPolicyEvaluation,
                FreeBusyCache,
                GALContacts,
                Messages,
                RecipientCache,
                RecoveryPoints,
                Reminders,
                RSSFeeds,
                Signal,
                SwssItems,
                Tasks,
            )

            for folder_cls in (
                ApplicationData,
                Calendar,
                Contacts,
                ConversationSettings,
                CrawlerData,
                DlpPolicyEvaluation,
                FreeBusyCache,
                GALContacts,
                Messages,
                RSSFeeds,
                RecipientCache,
                RecoveryPoints,
                Reminders,
                Signal,
                SwssItems,
                Tasks,
            ):
                if folder_cls.CONTAINER_CLASS == container_class:
                    return folder_cls
            raise KeyError()

        @classmethod
        def item_model_from_tag(cls, tag):
            try:
                return cls.ITEM_MODEL_MAP[tag]
            except KeyError:
                raise ValueError(f"Item type {tag} was unexpected in a {cls.__name__} folder")

        @classmethod
        def allowed_item_fields(cls, version):
            # Return non-ID fields of all item classes allowed in this folder type
            fields = set()
            for item_model in cls.supported_item_models:
                fields.update(set(item_model.supported_fields(version=version)))
            return fields

        def validate_item_field(self, field, version):
            FolderCollection(account=self.account, folders=[self]).validate_item_field(field=field, version=version)

        def normalize_fields(self, fields):
            # Takes a list of fieldnames, Field or FieldPath objects pointing to item fields. Turns them into FieldPath
            # objects and adds internal timezone fields if necessary. Assume fields are already validated.
            fields = list(fields)
            has_start, has_end = False, False
            for i, field_path in enumerate(fields):
                # Allow both Field and FieldPath instances and string field paths as input
                if isinstance(field_path, str):
                    field_path = FieldPath.from_string(field_path=field_path, folder=self)
                    fields[i] = field_path
                elif isinstance(field_path, Field):
                    field_path = FieldPath(field=field_path)
                    fields[i] = field_path
                if field_path.field.name == "start":
                    has_start = True
                elif field_path.field.name == "end":
                    has_end = True

            # For CalendarItem items, we want to inject internal timezone fields. See also CalendarItem.clean()
            if CalendarItem in self.supported_item_models:
                meeting_tz_field, start_tz_field, end_tz_field = CalendarItem.timezone_fields()
                if self.account.version.build < EXCHANGE_2010:
                    if has_start or has_end:
                        fields.append(FieldPath(field=meeting_tz_field))
                else:
                    if has_start:
                        fields.append(FieldPath(field=start_tz_field))
                    if has_end:
                        fields.append(FieldPath(field=end_tz_field))
            return fields

        @classmethod
        def get_item_field_by_fieldname(cls, fieldname):
            for item_model in cls.supported_item_models:
                with suppress(InvalidField):
                    return item_model.get_field_by_fieldname(fieldname)
            raise InvalidField(f"{fieldname!r} is not a valid field name on {cls.supported_item_models}")

        def get(self, *args, **kwargs):
            return FolderCollection(account=self.account, folders=[self]).get(*args, **kwargs)

        def all(self):
            return FolderCollection(account=self.account, folders=[self]).all()

        def none(self):
            return FolderCollection(account=self.account, folders=[self]).none()

        def filter(self, *args, **kwargs):
            return FolderCollection(account=self.account, folders=[self]).filter(*args, **kwargs)

        def exclude(self, *args, **kwargs):
            return FolderCollection(account=self.account, folders=[self]).exclude(*args, **kwargs)

        def people(self):
            # No point in using a FolderCollection because FindPeople only supports one folder
            return FolderCollection(account=self.account, folders=[self]).people()

        def bulk_create(self, items, *args, **kwargs):
            return self.account.bulk_create(folder=self, items=items, *args, **kwargs)

        def save(self, update_fields=None):
            from ..services import CreateFolder, UpdateFolder

            if self.id is None:
                # New folder
                if update_fields:
                    raise ValueError("'update_fields' is only valid for updates")
                res = CreateFolder(account=self.account).get(parent_folder=self.parent, folders=[self])
                self._id = self.ID_ELEMENT_CLS(res.id, res.changekey)
                self.root.add_folder(self)  # Add this folder to the cache
                return self

            # Update folder
            if not update_fields:
                # The fields to update was not specified explicitly. Update all fields where update is possible
                update_fields = []
                for f in self.supported_fields(version=self.account.version):
                    if f.is_read_only:
                        # These cannot be changed
                        continue
                    if (f.is_required or f.is_required_after_save) and (
                        getattr(self, f.name) is None or (f.is_list and not getattr(self, f.name))
                    ):
                        # These are required and cannot be deleted
                        continue
                    update_fields.append(f.name)
            res = UpdateFolder(account=self.account).get(folders=[(self, update_fields)])
            folder_id, changekey = res.id, res.changekey
            if self.id != folder_id:
                raise ValueError("ID mismatch")
            # Don't check changekey value. It may not change on no-op updates
            self.changekey = changekey
            self.root.update_folder(self)  # Update the folder in the cache
            return self

        def move(self, to_folder):
            from ..services import MoveFolder

            res = MoveFolder(account=self.account).get(folders=[self], to_folder=to_folder)
            folder_id, changekey = res.id, res.changekey
            if self.id != folder_id:
                raise ValueError("ID mismatch")
            # Don't check changekey value. It may not change on no-op moves
            self.changekey = changekey
            self.parent_folder_id = ParentFolderId(id=to_folder.id, changekey=to_folder.changekey)
            self.root.update_folder(self)  # Update the folder in the cache

        def delete(self, delete_type=HARD_DELETE):
            from ..services import DeleteFolder

            DeleteFolder(account=self.account).get(folders=[self], delete_type=delete_type)
            self.root.remove_folder(self)  # Remove the updated folder from the cache
            self._id = None

        def empty(self, delete_type=HARD_DELETE, delete_sub_folders=False):
            from ..services import EmptyFolder

            EmptyFolder(account=self.account).get(
                folders=[self], delete_type=delete_type, delete_sub_folders=delete_sub_folders
            )
            if delete_sub_folders:
                # We don't know exactly what was deleted, so invalidate the entire folder cache to be safe
                self.root.clear_cache()

        def wipe(self, page_size=None, chunk_size=None, _seen=None, _level=0):
            # Recursively deletes all items in this folder, and all sub-folders and their content. Attempts to protect
            # distinguished folders from being deleted. Use with caution!
            from .known_folders import Audits

            _seen = _seen or set()
            if self.id in _seen:
                raise RecursionError(f"We already tried to wipe {self}")
            if _level > 16:
                raise RecursionError(f"Max recursion level reached: {_level}")
            _seen.add(self.id)
            if isinstance(self, Audits):
                # Shortcircuit because this folder can have many items that are all non-deletable
                log.warning("Cannot wipe audits folder %s", self)
                return
            if self.is_distinguished and "recoverableitems" in self.DISTINGUISHED_FOLDER_ID:
                log.warning("Cannot wipe recoverable items folder %s", self)
                return
            log.warning("Wiping %s", self)
            has_distinguished_subfolders = any(f.is_distinguished for f in self.children)
            try:
                if has_distinguished_subfolders:
                    self.empty()
                else:
                    self.empty(delete_sub_folders=True)
            except ErrorRecoverableItemsAccessDenied:
                log.warning("Access denied to %s. Skipping", self)
                return
            except DELETE_FOLDER_ERRORS:
                try:
                    if has_distinguished_subfolders:
                        raise  # We already tried this
                    self.empty()
                except DELETE_FOLDER_ERRORS:
                    log.warning("Not allowed to empty %s. Trying to delete items instead", self)
                    kwargs = {}
                    if page_size is not None:
                        kwargs["page_size"] = page_size
                    if chunk_size is not None:
                        kwargs["chunk_size"] = chunk_size
                    try:
                        self.all().delete(**kwargs)
                    except DELETE_FOLDER_ERRORS:
                        log.warning("Not allowed to delete items in %s", self)
            _level += 1
            for f in self.children:
                f.wipe(page_size=page_size, chunk_size=chunk_size, _seen=_seen, _level=_level)
                # Remove non-distinguished children that are empty and have no sub-folders
                if f.is_deletable and not f.children:
                    log.warning("Deleting folder %s", f)
                    try:
                        f.delete()
                    except ErrorDeleteDistinguishedFolder:
                        log.warning("Tried to delete a distinguished folder (%s)", f)

        def test_access(self):
            """Does a simple FindItem to test (read) access to the folder. Maybe the account doesn't exist, maybe the
            service user doesn't have access to the calendar. This will throw the most common errors.
            """
            self.all().exists()
            return True

        @classmethod
        def _kwargs_from_elem(cls, elem, account):
            # Check for 'DisplayName' element before collecting kwargs because that clears the elements
            has_name_elem = elem.find(cls.get_field_by_fieldname("name").response_tag()) is not None
            kwargs = {f.name: f.from_xml(elem=elem, account=account) for f in cls.FIELDS}
            if has_name_elem and not kwargs["name"]:
                # When we request the 'DisplayName' property, some folders may still be returned with an empty value.
                # Assign a default name to these folders.
                kwargs["name"] = cls.DISTINGUISHED_FOLDER_ID
            return kwargs

        def to_id(self):
            if self.is_distinguished:
                # Don't add the changekey here. When modifying folder content, we usually don't care if others have changed
                # the folder content since we fetched the changekey.
                if self.account:
                    return DistinguishedFolderId(
                        id=self.DISTINGUISHED_FOLDER_ID, mailbox=Mailbox(email_address=self.account.primary_smtp_address)
                    )
                return DistinguishedFolderId(id=self.DISTINGUISHED_FOLDER_ID)
            if self.id:
                return FolderId(id=self.id, changekey=self.changekey)
            raise ValueError("Must be a distinguished folder or have an ID")

        @classmethod
        def resolve(cls, account, folder):
            # Resolve a single folder
            folders = list(FolderCollection(account=account, folders=[folder]).resolve())
            if not folders:
                raise ErrorFolderNotFound(f"Could not find folder {folder!r}")
            if len(folders) != 1:
                raise ValueError(f"Expected result length 1, but got {folders}")
            f = folders[0]
            if isinstance(f, Exception):
                raise f
            if f.__class__ != cls:
                raise ValueError(f"Expected folder {f!r} to be a {cls} instance")
            return f

        @require_id
        def refresh(self):
            fresh_folder = self.resolve(account=self.account, folder=self)
            if self.id != fresh_folder.id:
                raise ValueError("ID mismatch")
            # Apparently, the changekey may get updated
            for f in self.FIELDS:
                setattr(self, f.name, getattr(fresh_folder, f.name))
            return self

        @require_id
        def get_user_configuration(self, name, properties=None):
            from ..services import GetUserConfiguration
            from ..services.get_user_configuration import ALL

            if properties is None:
                properties = ALL
            return GetUserConfiguration(account=self.account).get(
                user_configuration_name=UserConfigurationNameMNS(name=name, folder=self),
                properties=properties,
            )

        @require_id
        def create_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None):
            from ..services import CreateUserConfiguration

            user_configuration = UserConfiguration(
                user_configuration_name=UserConfigurationName(name=name, folder=self),
                dictionary=dictionary,
                xml_data=xml_data,
                binary_data=binary_data,
            )
            return CreateUserConfiguration(account=self.account).get(user_configuration=user_configuration)

        @require_id
        def update_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None):
            from ..services import UpdateUserConfiguration

            user_configuration = UserConfiguration(
                user_configuration_name=UserConfigurationName(name=name, folder=self),
                dictionary=dictionary,
                xml_data=xml_data,
                binary_data=binary_data,
            )
            return UpdateUserConfiguration(account=self.account).get(user_configuration=user_configuration)

        @require_id
        def delete_user_configuration(self, name):
            from ..services import DeleteUserConfiguration

            return DeleteUserConfiguration(account=self.account).get(
                user_configuration_name=UserConfigurationNameMNS(name=name, folder=self)
            )

        @require_id
        def subscribe_to_pull(self, event_types=None, watermark=None, timeout=60):
            """Create a pull subscription.

            :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPull.EVENT_TYPES
            :param watermark: An event bookmark as returned by some sync services
            :param timeout: Timeout of the subscription, in minutes. Timeout is reset when the server receives a
            GetEvents request for this subscription.
            :return: The subscription ID and a watermark
            """
            from ..services import SubscribeToPull

            if event_types is None:
                event_types = SubscribeToPull.EVENT_TYPES
            return FolderCollection(account=self.account, folders=[self]).subscribe_to_pull(
                event_types=event_types,
                watermark=watermark,
                timeout=timeout,
            )

        @require_id
        def subscribe_to_push(self, callback_url, event_types=None, watermark=None, status_frequency=1):
            """Create a push subscription.

            :param callback_url: A client-defined URL that the server will call
            :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES
            :param watermark: An event bookmark as returned by some sync services
            :param status_frequency: The frequency, in minutes, that the callback URL will be called with.
            :return: The subscription ID and a watermark
            """
            from ..services import SubscribeToPush

            if event_types is None:
                event_types = SubscribeToPush.EVENT_TYPES
            return FolderCollection(account=self.account, folders=[self]).subscribe_to_push(
                event_types=event_types,
                watermark=watermark,
                status_frequency=status_frequency,
                callback_url=callback_url,
            )

        @require_id
        def subscribe_to_streaming(self, event_types=None):
            """Create a streaming subscription.

            :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES
            :return: The subscription ID
            """
            from ..services import SubscribeToStreaming

            if event_types is None:
                event_types = SubscribeToStreaming.EVENT_TYPES
            return FolderCollection(account=self.account, folders=[self]).subscribe_to_streaming(event_types=event_types)

        @require_id
        def pull_subscription(self, **kwargs):
            return PullSubscription(folder=self, **kwargs)

        @require_id
        def push_subscription(self, **kwargs):
            return PushSubscription(folder=self, **kwargs)

        @require_id
        def streaming_subscription(self, **kwargs):
            return StreamingSubscription(folder=self, **kwargs)

        def unsubscribe(self, subscription_id):
            """Unsubscribe. Only applies to pull and streaming notifications.

            :param subscription_id: A subscription ID as acquired by .subscribe_to_[pull|streaming]()
            :return: True

            This method doesn't need the current folder instance, but it makes sense to keep the method along the other
            sync methods.
            """
            from ..services import Unsubscribe

            return Unsubscribe(account=self.account).get(subscription_id=subscription_id)

        def sync_items(self, sync_state=None, only_fields=None, ignore=None, max_changes_returned=None, sync_scope=None):
            """Return all item changes to a folder, as a generator. If sync_state is specified, get all item changes after
            this sync state. After fully consuming the generator, self.item_sync_state will hold the new sync state.

            :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service.
            :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields
            :param ignore: A list of Item IDs to ignore in the sync
            :param max_changes_returned: The max number of change
            :param sync_scope: Specify whether to return just items, or items and folder associated information. Possible
               values are specified in SyncFolderItems.SYNC_SCOPES
            :return: A generator of (change_type, item) tuples
            """
            if not sync_state:
                sync_state = self.item_sync_state
            try:
                yield from FolderCollection(account=self.account, folders=[self]).sync_items(
                    sync_state=sync_state,
                    only_fields=only_fields,
                    ignore=ignore,
                    max_changes_returned=max_changes_returned,
                    sync_scope=sync_scope,
                )
            except SyncCompleted as e:
                # Set the new sync state on the folder instance
                self.item_sync_state = e.sync_state

        def sync_hierarchy(self, sync_state=None, only_fields=None):
            """Return all folder changes to a folder hierarchy, as a generator. If sync_state is specified, get all folder
            changes after this sync state. After fully consuming the generator, self.folder_sync_state will hold the new
            sync state.

            :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service.
            :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields
            :return:
            """
            if not sync_state:
                sync_state = self.folder_sync_state
            try:
                yield from FolderCollection(account=self.account, folders=[self]).sync_hierarchy(
                    sync_state=sync_state,
                    only_fields=only_fields,
                )
            except SyncCompleted as e:
                # Set the new sync state on the folder instance
                self.folder_sync_state = e.sync_state

        def get_events(self, subscription_id, watermark):
            """Get events since the given watermark. Non-blocking.

            :param subscription_id: A subscription ID as acquired by .subscribe_to_[pull|push]()
            :param watermark: Either the watermark from the subscription, or as returned by the last .get_events() call.
            :return: A Notification object containing a list of events

            This method doesn't need the current folder instance, but it makes sense to keep the method along the other
            sync methods.
            """
            from ..services import GetEvents

            svc = GetEvents(account=self.account)
            while True:
                notification = svc.get(subscription_id=subscription_id, watermark=watermark)
                yield notification
                if not notification.more_events:
                    break

        def get_streaming_events(self, subscription_id_or_ids, connection_timeout=1, max_notifications_returned=None):
            """Get events since the subscription was created, in streaming mode. This method will block as many minutes
            as specified by 'connection_timeout'.

            :param subscription_id_or_ids: A subscription ID, or list of IDs, as acquired by .subscribe_to_streaming()
            :param connection_timeout: Timeout of the connection, in minutes. The connection is closed after this timeout
            is reached.
            :param max_notifications_returned: If specified, will exit after receiving this number of notifications
            :return: A generator of Notification objects, each containing a list of events

            This method doesn't need the current folder instance, but it makes sense to keep the method along the other
            sync methods.
            """
            from ..services import GetStreamingEvents

            svc = GetStreamingEvents(account=self.account)
            subscription_ids = (
                subscription_id_or_ids
                if is_iterable(subscription_id_or_ids, generators_allowed=True)
                else [subscription_id_or_ids]
            )
            for i, notification in enumerate(
                svc.call(subscription_ids=subscription_ids, connection_timeout=connection_timeout), start=1
            ):
                yield notification
                if max_notifications_returned and i >= max_notifications_returned:
                    svc.stop_streaming()
                    break

        def __floordiv__(self, other):
            """Support the some_folder // 'child_folder' // 'child_of_child_folder' navigation syntax.

            Works like as __truediv__ but does not touch the folder cache.

            This is useful if the folder hierarchy contains a huge number of folders, and you don't want to fetch them all

            :param other:
            :return:
            """
            if other == "..":
                raise ValueError("Cannot get parent without a folder cache")

            if other == ".":
                return self

            # Assume an exact match on the folder name in a shallow search will only return at most one folder
            try:
                return SingleFolderQuerySet(account=self.account, folder=self).depth(SHALLOW_FOLDERS).get(name=other)
            except DoesNotExist:
                raise ErrorFolderNotFound(f"No subfolder with name {other!r}")

        def __truediv__(self, other):
            """Support the some_folder / 'child_folder' / 'child_of_child_folder' navigation syntax."""
            if other == "..":
                if not self.parent:
                    raise ValueError("Already at top")
                return self.parent
            if other == ".":
                return self
            for c in self.children:
                if c.name == other:
                    return c
            raise ErrorFolderNotFound(f"No subfolder with name {other!r}")

        def __repr__(self):
            return self.__class__.__name__ + repr(
                (
                    self.root,
                    self.name,
                    self.total_count,
                    self.unread_count,
                    self.child_folder_count,
                    self.folder_class,
                    self.id,
                    self.changekey,
                )
            )

        def __str__(self):
            return f"{self.__class__.__name__} ({self.name})"

    class Folder(BaseFolder):
        """MSDN: https://docs.microsoft.com/en-us/exchange/client-developer/web-service-reference/folder"""

        permission_set = PermissionSetField(field_uri="folder:PermissionSet", supported_from=EXCHANGE_2007_SP1)
        effective_rights = EffectiveRightsField(
            field_uri="folder:EffectiveRights", is_read_only=True, supported_from=EXCHANGE_2007_SP1
        )

        __slots__ = ("_root",)

        def __init__(self, **kwargs):
            self._root = kwargs.pop("root", None)  # This is a pointer to the root of the folder hierarchy
            parent = kwargs.pop("parent", None)
            if parent:
                if self.root:
                    if parent.root != self.root:
                        raise ValueError("'parent.root' must match 'root'")
                else:
                    self.root = parent.root
                if "parent_folder_id" in kwargs and parent.id != kwargs["parent_folder_id"]:
                    raise ValueError("'parent_folder_id' must match 'parent' ID")
                kwargs["parent_folder_id"] = ParentFolderId(id=parent.id, changekey=parent.changekey)
            super().__init__(**kwargs)

        @property
        def account(self):
            if self.root is None:
                return None
            return self.root.account

        @property
        def root(self):
            return self._root

        @root.setter
        def root(self, value):
            self._root = value

        @classmethod
        def register(cls, *args, **kwargs):
            if cls is not Folder:
                raise TypeError("For folders, custom fields must be registered on the Folder class")
            return super().register(*args, **kwargs)

        @classmethod
        def deregister(cls, *args, **kwargs):
            if cls is not Folder:
                raise TypeError("For folders, custom fields must be registered on the Folder class")
            return super().deregister(*args, **kwargs)

        @classmethod
        def get_distinguished(cls, root):
            """Get the distinguished folder for this folder class.

            :param root:
            :return:
            """
            try:
                return cls.resolve(
                    account=root.account, folder=cls(root=root, name=cls.DISTINGUISHED_FOLDER_ID, is_distinguished=True)
                )
            except MISSING_FOLDER_ERRORS:
                raise ErrorFolderNotFound(f"Could not find distinguished folder {cls.DISTINGUISHED_FOLDER_ID!r}")

        @property
        def parent(self):
            if not self.parent_folder_id:
                return None
            if self.parent_folder_id.id == self.id:
                # Some folders have a parent that references itself. Avoid circular references here
                return None
            return self.root.get_folder(self.parent_folder_id)

        @parent.setter
        def parent(self, value):
            if value is None:
                self.parent_folder_id = None
            else:
                if not isinstance(value, BaseFolder):
                    raise InvalidTypeError("value", value, BaseFolder)
                self.root = value.root
                self.parent_folder_id = ParentFolderId(id=value.id, changekey=value.changekey)

        def clean(self, version=None):
            from .roots import RootOfHierarchy

            super().clean(version=version)
            if self.root and not isinstance(self.root, RootOfHierarchy):
                raise InvalidTypeError("root", self.root, RootOfHierarchy)

        @classmethod
        def from_xml_with_root(cls, elem, root):
            folder = cls.from_xml(elem=elem, account=root.account)
            folder_cls = cls
            if cls == Folder:
                # We were called on the generic Folder class. Try to find a more specific class to return objects as.
                #
                # The "FolderClass" element value is the only indication we have in the FindFolder response of which
                # folder class we should create the folder with. And many folders share the same 'FolderClass' value, e.g.
                # Inbox and DeletedItems. We want to distinguish between these because otherwise we can't locate the right
                # folders types for e.g. Account.inbox and Account.trash.
                #
                # We should be able to just use the name, but apparently default folder names can be renamed to a set of
                # localized names using a PowerShell command:
                # https://docs.microsoft.com/en-us/powershell/module/exchange/client-access/Set-MailboxRegionalConfiguration
                #
                # Instead, search for a folder class using the localized name. If none are found, fall back to getting the
                # folder class by the "FolderClass" value.
                #
                # The returned XML may contain neither folder class nor name. In that case, we default to the generic
                # Folder class.
                if folder.name:
                    with suppress(KeyError):
                        # TODO: fld_class.LOCALIZED_NAMES is most definitely neither complete nor authoritative
                        folder_cls = root.folder_cls_from_folder_name(folder_name=folder.name, locale=root.account.locale)
                        log.debug("Folder class %s matches localized folder name %s", folder_cls, folder.name)
                if folder.folder_class and folder_cls == Folder:
                    with suppress(KeyError):
                        folder_cls = cls.folder_cls_from_container_class(container_class=folder.folder_class)
                        log.debug(
                            "Folder class %s matches container class %s (%s)", folder_cls, folder.folder_class, folder.name
                        )
                if folder_cls == Folder:
                    log.debug("Fallback to class Folder (folder_class %s, name %s)", folder.folder_class, folder.name)
            return folder_cls(root=root, **{f.name: getattr(folder, f.name) for f in folder.FIELDS})

## Classes

`class BaseFolder (**kwargs)`

  Base class for all classes that implement a folder.

  Expand source code

      class BaseFolder(RegisterMixIn, SearchableMixIn, SupportedVersionClassMixIn, metaclass=EWSMeta):
          """Base class for all classes that implement a folder."""

          ELEMENT_NAME = "Folder"
          NAMESPACE = TNS
          # See https://docs.microsoft.com/en-us/exchange/client-developer/web-service-reference/distinguishedfolderid
          DISTINGUISHED_FOLDER_ID = None
          # Default item type for this folder. See
          # https://docs.microsoft.com/en-us/openspecs/exchange_server_protocols/ms-oxosfld/68a85898-84fe-43c4-b166-4711c13cdd61
          CONTAINER_CLASS = None
          supported_item_models = ITEM_CLASSES  # The Item types that this folder can contain. Default is all
          # Whether this folder type is allowed with the GetFolder service
          get_folder_allowed = True
          DEFAULT_FOLDER_TRAVERSAL_DEPTH = DEEP_FOLDERS
          DEFAULT_ITEM_TRAVERSAL_DEPTH = SHALLOW_ITEMS
          LOCALIZED_NAMES = {}  # A map of (str)locale: (tuple)localized_folder_names
          ITEM_MODEL_MAP = {cls.response_tag(): cls for cls in ITEM_CLASSES}
          ID_ELEMENT_CLS = FolderId

          _id = IdElementField(field_uri="folder:FolderId", value_cls=ID_ELEMENT_CLS)
          parent_folder_id = EWSElementField(field_uri="folder:ParentFolderId", value_cls=ParentFolderId, is_read_only=True)
          folder_class = CharField(field_uri="folder:FolderClass", is_required_after_save=True)
          name = CharField(field_uri="folder:DisplayName")
          total_count = IntegerField(field_uri="folder:TotalCount", is_read_only=True)
          child_folder_count = IntegerField(field_uri="folder:ChildFolderCount", is_read_only=True)
          unread_count = IntegerField(field_uri="folder:UnreadCount", is_read_only=True)

          __slots__ = "is_distinguished", "item_sync_state", "folder_sync_state"

          # Used to register extended properties
          INSERT_AFTER_FIELD = "child_folder_count"

          def __init__(self, **kwargs):
              self.is_distinguished = kwargs.pop("is_distinguished", False)
              self.item_sync_state = kwargs.pop("item_sync_state", None)
              self.folder_sync_state = kwargs.pop("folder_sync_state", None)
              super().__init__(**kwargs)

          @property
          @abc.abstractmethod
          def account(self):
              """Return the account this folder belongs to"""

          @property
          @abc.abstractmethod
          def root(self):
              """Return the root folder this folder belongs to"""

          @property
          @abc.abstractmethod
          def parent(self):
              """Return the parent folder of this folder"""

          @property
          def is_deletable(self):
              return not self.is_distinguished

          def clean(self, version=None):
              super().clean(version=version)
              # Set a default folder class for new folders. A folder class cannot be changed after saving.
              if self.id is None and self.folder_class is None:
                  self.folder_class = self.CONTAINER_CLASS

          @property
          def children(self):
              # It's dangerous to return a generator here because we may then call methods on a child that result in the
              # cache being updated while it's iterated.
              return FolderCollection(account=self.account, folders=self.root.get_children(self))

          @property
          def parts(self):
              parts = [self]
              f = self.parent
              while f:
                  parts.insert(0, f)
                  f = f.parent
              return parts

          @property
          def absolute(self):
              return "".join(f"/{p.name}" for p in self.parts)

          def _walk(self):
              for c in self.children:
                  yield c
                  yield from c.walk()

          def walk(self):
              return FolderCollection(account=self.account, folders=self._walk())

          def _glob(self, pattern):
              split_pattern = pattern.rsplit("/", 1)
              head, tail = (split_pattern[0], None) if len(split_pattern) == 1 else split_pattern
              if head == "":
                  # We got an absolute path. Restart globbing at root
                  yield from self.root.glob(tail or "*")
              elif head == "..":
                  # Relative path with reference to parent. Restart globbing at parent
                  if not self.parent:
                      raise ValueError("Already at top")
                  yield from self.parent.glob(tail or "*")
              elif head == "**":
                  # Match anything here or in any sub-folder at arbitrary depth
                  for c in self.walk():
                      # fnmatch() may be case-sensitive depending on operating system:
                      # force a case-insensitive match since case appears not to
                      # matter for folders in Exchange
                      if fnmatch(c.name.lower(), (tail or "*").lower()):
                          yield c
              else:
                  # Regular pattern
                  for c in self.children:
                      # See note above on fnmatch() case-sensitivity
                      if not fnmatch(c.name.lower(), head.lower()):
                          continue
                      if tail is None:
                          yield c
                          continue
                      yield from c.glob(tail)

          def glob(self, pattern):
              return FolderCollection(account=self.account, folders=self._glob(pattern))

          def tree(self):
              """Return a string representation of the folder structure of this folder. Example:

              root
              ├── inbox
              │   └── todos
              └── archive
                  ├── Last Job
                  ├── exchangelib issues
                  └── Mom
              """
              tree = f"{self.name}\n"
              children = list(self.children)
              for i, c in enumerate(sorted(children, key=attrgetter("name")), start=1):
                  nodes = c.tree().split("\n")
                  for j, node in enumerate(nodes, start=1):
                      if i != len(children) and j == 1:
                          # Not the last child, but the first node, which is the name of the child
                          tree += f"├── {node}\n"
                      elif i != len(children) and j > 1:
                          # Not the last child, and not name of child
                          tree += f"│   {node}\n"
                      elif i == len(children) and j == 1:
                          # Not the last child, but the first node, which is the name of the child
                          tree += f"└── {node}\n"
                      else:  # Last child and not name of child
                          tree += f"    {node}\n"
              return tree.strip()

          @property
          def has_distinguished_name(self):
              return self.name and self.DISTINGUISHED_FOLDER_ID and self.name.lower() == self.DISTINGUISHED_FOLDER_ID.lower()

          @classmethod
          def localized_names(cls, locale):
              # Return localized names for a specific locale. If no locale-specific names exist, return the default names,
              # if any.
              return tuple(s.lower() for s in cls.LOCALIZED_NAMES.get(locale, cls.LOCALIZED_NAMES.get(None, [])))

          @staticmethod
          def folder_cls_from_container_class(container_class):
              """Return a reasonable folder class given a container class, e.g. 'IPF.Note'. Don't iterate WELLKNOWN_FOLDERS
              because many folder classes have the same CONTAINER_CLASS.

              :param container_class:
              :return:
              """
              from .known_folders import (
                  ApplicationData,
                  Calendar,
                  Contacts,
                  ConversationSettings,
                  CrawlerData,
                  DlpPolicyEvaluation,
                  FreeBusyCache,
                  GALContacts,
                  Messages,
                  RecipientCache,
                  RecoveryPoints,
                  Reminders,
                  RSSFeeds,
                  Signal,
                  SwssItems,
                  Tasks,
              )

              for folder_cls in (
                  ApplicationData,
                  Calendar,
                  Contacts,
                  ConversationSettings,
                  CrawlerData,
                  DlpPolicyEvaluation,
                  FreeBusyCache,
                  GALContacts,
                  Messages,
                  RSSFeeds,
                  RecipientCache,
                  RecoveryPoints,
                  Reminders,
                  Signal,
                  SwssItems,
                  Tasks,
              ):
                  if folder_cls.CONTAINER_CLASS == container_class:
                      return folder_cls
              raise KeyError()

          @classmethod
          def item_model_from_tag(cls, tag):
              try:
                  return cls.ITEM_MODEL_MAP[tag]
              except KeyError:
                  raise ValueError(f"Item type {tag} was unexpected in a {cls.__name__} folder")

          @classmethod
          def allowed_item_fields(cls, version):
              # Return non-ID fields of all item classes allowed in this folder type
              fields = set()
              for item_model in cls.supported_item_models:
                  fields.update(set(item_model.supported_fields(version=version)))
              return fields

          def validate_item_field(self, field, version):
              FolderCollection(account=self.account, folders=[self]).validate_item_field(field=field, version=version)

          def normalize_fields(self, fields):
              # Takes a list of fieldnames, Field or FieldPath objects pointing to item fields. Turns them into FieldPath
              # objects and adds internal timezone fields if necessary. Assume fields are already validated.
              fields = list(fields)
              has_start, has_end = False, False
              for i, field_path in enumerate(fields):
                  # Allow both Field and FieldPath instances and string field paths as input
                  if isinstance(field_path, str):
                      field_path = FieldPath.from_string(field_path=field_path, folder=self)
                      fields[i] = field_path
                  elif isinstance(field_path, Field):
                      field_path = FieldPath(field=field_path)
                      fields[i] = field_path
                  if field_path.field.name == "start":
                      has_start = True
                  elif field_path.field.name == "end":
                      has_end = True

              # For CalendarItem items, we want to inject internal timezone fields. See also CalendarItem.clean()
              if CalendarItem in self.supported_item_models:
                  meeting_tz_field, start_tz_field, end_tz_field = CalendarItem.timezone_fields()
                  if self.account.version.build < EXCHANGE_2010:
                      if has_start or has_end:
                          fields.append(FieldPath(field=meeting_tz_field))
                  else:
                      if has_start:
                          fields.append(FieldPath(field=start_tz_field))
                      if has_end:
                          fields.append(FieldPath(field=end_tz_field))
              return fields

          @classmethod
          def get_item_field_by_fieldname(cls, fieldname):
              for item_model in cls.supported_item_models:
                  with suppress(InvalidField):
                      return item_model.get_field_by_fieldname(fieldname)
              raise InvalidField(f"{fieldname!r} is not a valid field name on {cls.supported_item_models}")

          def get(self, *args, **kwargs):
              return FolderCollection(account=self.account, folders=[self]).get(*args, **kwargs)

          def all(self):
              return FolderCollection(account=self.account, folders=[self]).all()

          def none(self):
              return FolderCollection(account=self.account, folders=[self]).none()

          def filter(self, *args, **kwargs):
              return FolderCollection(account=self.account, folders=[self]).filter(*args, **kwargs)

          def exclude(self, *args, **kwargs):
              return FolderCollection(account=self.account, folders=[self]).exclude(*args, **kwargs)

          def people(self):
              # No point in using a FolderCollection because FindPeople only supports one folder
              return FolderCollection(account=self.account, folders=[self]).people()

          def bulk_create(self, items, *args, **kwargs):
              return self.account.bulk_create(folder=self, items=items, *args, **kwargs)

          def save(self, update_fields=None):
              from ..services import CreateFolder, UpdateFolder

              if self.id is None:
                  # New folder
                  if update_fields:
                      raise ValueError("'update_fields' is only valid for updates")
                  res = CreateFolder(account=self.account).get(parent_folder=self.parent, folders=[self])
                  self._id = self.ID_ELEMENT_CLS(res.id, res.changekey)
                  self.root.add_folder(self)  # Add this folder to the cache
                  return self

              # Update folder
              if not update_fields:
                  # The fields to update was not specified explicitly. Update all fields where update is possible
                  update_fields = []
                  for f in self.supported_fields(version=self.account.version):
                      if f.is_read_only:
                          # These cannot be changed
                          continue
                      if (f.is_required or f.is_required_after_save) and (
                          getattr(self, f.name) is None or (f.is_list and not getattr(self, f.name))
                      ):
                          # These are required and cannot be deleted
                          continue
                      update_fields.append(f.name)
              res = UpdateFolder(account=self.account).get(folders=[(self, update_fields)])
              folder_id, changekey = res.id, res.changekey
              if self.id != folder_id:
                  raise ValueError("ID mismatch")
              # Don't check changekey value. It may not change on no-op updates
              self.changekey = changekey
              self.root.update_folder(self)  # Update the folder in the cache
              return self

          def move(self, to_folder):
              from ..services import MoveFolder

              res = MoveFolder(account=self.account).get(folders=[self], to_folder=to_folder)
              folder_id, changekey = res.id, res.changekey
              if self.id != folder_id:
                  raise ValueError("ID mismatch")
              # Don't check changekey value. It may not change on no-op moves
              self.changekey = changekey
              self.parent_folder_id = ParentFolderId(id=to_folder.id, changekey=to_folder.changekey)
              self.root.update_folder(self)  # Update the folder in the cache

          def delete(self, delete_type=HARD_DELETE):
              from ..services import DeleteFolder

              DeleteFolder(account=self.account).get(folders=[self], delete_type=delete_type)
              self.root.remove_folder(self)  # Remove the updated folder from the cache
              self._id = None

          def empty(self, delete_type=HARD_DELETE, delete_sub_folders=False):
              from ..services import EmptyFolder

              EmptyFolder(account=self.account).get(
                  folders=[self], delete_type=delete_type, delete_sub_folders=delete_sub_folders
              )
              if delete_sub_folders:
                  # We don't know exactly what was deleted, so invalidate the entire folder cache to be safe
                  self.root.clear_cache()

          def wipe(self, page_size=None, chunk_size=None, _seen=None, _level=0):
              # Recursively deletes all items in this folder, and all sub-folders and their content. Attempts to protect
              # distinguished folders from being deleted. Use with caution!
              from .known_folders import Audits

              _seen = _seen or set()
              if self.id in _seen:
                  raise RecursionError(f"We already tried to wipe {self}")
              if _level > 16:
                  raise RecursionError(f"Max recursion level reached: {_level}")
              _seen.add(self.id)
              if isinstance(self, Audits):
                  # Shortcircuit because this folder can have many items that are all non-deletable
                  log.warning("Cannot wipe audits folder %s", self)
                  return
              if self.is_distinguished and "recoverableitems" in self.DISTINGUISHED_FOLDER_ID:
                  log.warning("Cannot wipe recoverable items folder %s", self)
                  return
              log.warning("Wiping %s", self)
              has_distinguished_subfolders = any(f.is_distinguished for f in self.children)
              try:
                  if has_distinguished_subfolders:
                      self.empty()
                  else:
                      self.empty(delete_sub_folders=True)
              except ErrorRecoverableItemsAccessDenied:
                  log.warning("Access denied to %s. Skipping", self)
                  return
              except DELETE_FOLDER_ERRORS:
                  try:
                      if has_distinguished_subfolders:
                          raise  # We already tried this
                      self.empty()
                  except DELETE_FOLDER_ERRORS:
                      log.warning("Not allowed to empty %s. Trying to delete items instead", self)
                      kwargs = {}
                      if page_size is not None:
                          kwargs["page_size"] = page_size
                      if chunk_size is not None:
                          kwargs["chunk_size"] = chunk_size
                      try:
                          self.all().delete(**kwargs)
                      except DELETE_FOLDER_ERRORS:
                          log.warning("Not allowed to delete items in %s", self)
              _level += 1
              for f in self.children:
                  f.wipe(page_size=page_size, chunk_size=chunk_size, _seen=_seen, _level=_level)
                  # Remove non-distinguished children that are empty and have no sub-folders
                  if f.is_deletable and not f.children:
                      log.warning("Deleting folder %s", f)
                      try:
                          f.delete()
                      except ErrorDeleteDistinguishedFolder:
                          log.warning("Tried to delete a distinguished folder (%s)", f)

          def test_access(self):
              """Does a simple FindItem to test (read) access to the folder. Maybe the account doesn't exist, maybe the
              service user doesn't have access to the calendar. This will throw the most common errors.
              """
              self.all().exists()
              return True

          @classmethod
          def _kwargs_from_elem(cls, elem, account):
              # Check for 'DisplayName' element before collecting kwargs because that clears the elements
              has_name_elem = elem.find(cls.get_field_by_fieldname("name").response_tag()) is not None
              kwargs = {f.name: f.from_xml(elem=elem, account=account) for f in cls.FIELDS}
              if has_name_elem and not kwargs["name"]:
                  # When we request the 'DisplayName' property, some folders may still be returned with an empty value.
                  # Assign a default name to these folders.
                  kwargs["name"] = cls.DISTINGUISHED_FOLDER_ID
              return kwargs

          def to_id(self):
              if self.is_distinguished:
                  # Don't add the changekey here. When modifying folder content, we usually don't care if others have changed
                  # the folder content since we fetched the changekey.
                  if self.account:
                      return DistinguishedFolderId(
                          id=self.DISTINGUISHED_FOLDER_ID, mailbox=Mailbox(email_address=self.account.primary_smtp_address)
                      )
                  return DistinguishedFolderId(id=self.DISTINGUISHED_FOLDER_ID)
              if self.id:
                  return FolderId(id=self.id, changekey=self.changekey)
              raise ValueError("Must be a distinguished folder or have an ID")

          @classmethod
          def resolve(cls, account, folder):
              # Resolve a single folder
              folders = list(FolderCollection(account=account, folders=[folder]).resolve())
              if not folders:
                  raise ErrorFolderNotFound(f"Could not find folder {folder!r}")
              if len(folders) != 1:
                  raise ValueError(f"Expected result length 1, but got {folders}")
              f = folders[0]
              if isinstance(f, Exception):
                  raise f
              if f.__class__ != cls:
                  raise ValueError(f"Expected folder {f!r} to be a {cls} instance")
              return f

          @require_id
          def refresh(self):
              fresh_folder = self.resolve(account=self.account, folder=self)
              if self.id != fresh_folder.id:
                  raise ValueError("ID mismatch")
              # Apparently, the changekey may get updated
              for f in self.FIELDS:
                  setattr(self, f.name, getattr(fresh_folder, f.name))
              return self

          @require_id
          def get_user_configuration(self, name, properties=None):
              from ..services import GetUserConfiguration
              from ..services.get_user_configuration import ALL

              if properties is None:
                  properties = ALL
              return GetUserConfiguration(account=self.account).get(
                  user_configuration_name=UserConfigurationNameMNS(name=name, folder=self),
                  properties=properties,
              )

          @require_id
          def create_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None):
              from ..services import CreateUserConfiguration

              user_configuration = UserConfiguration(
                  user_configuration_name=UserConfigurationName(name=name, folder=self),
                  dictionary=dictionary,
                  xml_data=xml_data,
                  binary_data=binary_data,
              )
              return CreateUserConfiguration(account=self.account).get(user_configuration=user_configuration)

          @require_id
          def update_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None):
              from ..services import UpdateUserConfiguration

              user_configuration = UserConfiguration(
                  user_configuration_name=UserConfigurationName(name=name, folder=self),
                  dictionary=dictionary,
                  xml_data=xml_data,
                  binary_data=binary_data,
              )
              return UpdateUserConfiguration(account=self.account).get(user_configuration=user_configuration)

          @require_id
          def delete_user_configuration(self, name):
              from ..services import DeleteUserConfiguration

              return DeleteUserConfiguration(account=self.account).get(
                  user_configuration_name=UserConfigurationNameMNS(name=name, folder=self)
              )

          @require_id
          def subscribe_to_pull(self, event_types=None, watermark=None, timeout=60):
              """Create a pull subscription.

              :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPull.EVENT_TYPES
              :param watermark: An event bookmark as returned by some sync services
              :param timeout: Timeout of the subscription, in minutes. Timeout is reset when the server receives a
              GetEvents request for this subscription.
              :return: The subscription ID and a watermark
              """
              from ..services import SubscribeToPull

              if event_types is None:
                  event_types = SubscribeToPull.EVENT_TYPES
              return FolderCollection(account=self.account, folders=[self]).subscribe_to_pull(
                  event_types=event_types,
                  watermark=watermark,
                  timeout=timeout,
              )

          @require_id
          def subscribe_to_push(self, callback_url, event_types=None, watermark=None, status_frequency=1):
              """Create a push subscription.

              :param callback_url: A client-defined URL that the server will call
              :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES
              :param watermark: An event bookmark as returned by some sync services
              :param status_frequency: The frequency, in minutes, that the callback URL will be called with.
              :return: The subscription ID and a watermark
              """
              from ..services import SubscribeToPush

              if event_types is None:
                  event_types = SubscribeToPush.EVENT_TYPES
              return FolderCollection(account=self.account, folders=[self]).subscribe_to_push(
                  event_types=event_types,
                  watermark=watermark,
                  status_frequency=status_frequency,
                  callback_url=callback_url,
              )

          @require_id
          def subscribe_to_streaming(self, event_types=None):
              """Create a streaming subscription.

              :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES
              :return: The subscription ID
              """
              from ..services import SubscribeToStreaming

              if event_types is None:
                  event_types = SubscribeToStreaming.EVENT_TYPES
              return FolderCollection(account=self.account, folders=[self]).subscribe_to_streaming(event_types=event_types)

          @require_id
          def pull_subscription(self, **kwargs):
              return PullSubscription(folder=self, **kwargs)

          @require_id
          def push_subscription(self, **kwargs):
              return PushSubscription(folder=self, **kwargs)

          @require_id
          def streaming_subscription(self, **kwargs):
              return StreamingSubscription(folder=self, **kwargs)

          def unsubscribe(self, subscription_id):
              """Unsubscribe. Only applies to pull and streaming notifications.

              :param subscription_id: A subscription ID as acquired by .subscribe_to_[pull|streaming]()
              :return: True

              This method doesn't need the current folder instance, but it makes sense to keep the method along the other
              sync methods.
              """
              from ..services import Unsubscribe

              return Unsubscribe(account=self.account).get(subscription_id=subscription_id)

          def sync_items(self, sync_state=None, only_fields=None, ignore=None, max_changes_returned=None, sync_scope=None):
              """Return all item changes to a folder, as a generator. If sync_state is specified, get all item changes after
              this sync state. After fully consuming the generator, self.item_sync_state will hold the new sync state.

              :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service.
              :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields
              :param ignore: A list of Item IDs to ignore in the sync
              :param max_changes_returned: The max number of change
              :param sync_scope: Specify whether to return just items, or items and folder associated information. Possible
                 values are specified in SyncFolderItems.SYNC_SCOPES
              :return: A generator of (change_type, item) tuples
              """
              if not sync_state:
                  sync_state = self.item_sync_state
              try:
                  yield from FolderCollection(account=self.account, folders=[self]).sync_items(
                      sync_state=sync_state,
                      only_fields=only_fields,
                      ignore=ignore,
                      max_changes_returned=max_changes_returned,
                      sync_scope=sync_scope,
                  )
              except SyncCompleted as e:
                  # Set the new sync state on the folder instance
                  self.item_sync_state = e.sync_state

          def sync_hierarchy(self, sync_state=None, only_fields=None):
              """Return all folder changes to a folder hierarchy, as a generator. If sync_state is specified, get all folder
              changes after this sync state. After fully consuming the generator, self.folder_sync_state will hold the new
              sync state.

              :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service.
              :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields
              :return:
              """
              if not sync_state:
                  sync_state = self.folder_sync_state
              try:
                  yield from FolderCollection(account=self.account, folders=[self]).sync_hierarchy(
                      sync_state=sync_state,
                      only_fields=only_fields,
                  )
              except SyncCompleted as e:
                  # Set the new sync state on the folder instance
                  self.folder_sync_state = e.sync_state

          def get_events(self, subscription_id, watermark):
              """Get events since the given watermark. Non-blocking.

              :param subscription_id: A subscription ID as acquired by .subscribe_to_[pull|push]()
              :param watermark: Either the watermark from the subscription, or as returned by the last .get_events() call.
              :return: A Notification object containing a list of events

              This method doesn't need the current folder instance, but it makes sense to keep the method along the other
              sync methods.
              """
              from ..services import GetEvents

              svc = GetEvents(account=self.account)
              while True:
                  notification = svc.get(subscription_id=subscription_id, watermark=watermark)
                  yield notification
                  if not notification.more_events:
                      break

          def get_streaming_events(self, subscription_id_or_ids, connection_timeout=1, max_notifications_returned=None):
              """Get events since the subscription was created, in streaming mode. This method will block as many minutes
              as specified by 'connection_timeout'.

              :param subscription_id_or_ids: A subscription ID, or list of IDs, as acquired by .subscribe_to_streaming()
              :param connection_timeout: Timeout of the connection, in minutes. The connection is closed after this timeout
              is reached.
              :param max_notifications_returned: If specified, will exit after receiving this number of notifications
              :return: A generator of Notification objects, each containing a list of events

              This method doesn't need the current folder instance, but it makes sense to keep the method along the other
              sync methods.
              """
              from ..services import GetStreamingEvents

              svc = GetStreamingEvents(account=self.account)
              subscription_ids = (
                  subscription_id_or_ids
                  if is_iterable(subscription_id_or_ids, generators_allowed=True)
                  else [subscription_id_or_ids]
              )
              for i, notification in enumerate(
                  svc.call(subscription_ids=subscription_ids, connection_timeout=connection_timeout), start=1
              ):
                  yield notification
                  if max_notifications_returned and i >= max_notifications_returned:
                      svc.stop_streaming()
                      break

          def __floordiv__(self, other):
              """Support the some_folder // 'child_folder' // 'child_of_child_folder' navigation syntax.

              Works like as __truediv__ but does not touch the folder cache.

              This is useful if the folder hierarchy contains a huge number of folders, and you don't want to fetch them all

              :param other:
              :return:
              """
              if other == "..":
                  raise ValueError("Cannot get parent without a folder cache")

              if other == ".":
                  return self

              # Assume an exact match on the folder name in a shallow search will only return at most one folder
              try:
                  return SingleFolderQuerySet(account=self.account, folder=self).depth(SHALLOW_FOLDERS).get(name=other)
              except DoesNotExist:
                  raise ErrorFolderNotFound(f"No subfolder with name {other!r}")

          def __truediv__(self, other):
              """Support the some_folder / 'child_folder' / 'child_of_child_folder' navigation syntax."""
              if other == "..":
                  if not self.parent:
                      raise ValueError("Already at top")
                  return self.parent
              if other == ".":
                  return self
              for c in self.children:
                  if c.name == other:
                      return c
              raise ErrorFolderNotFound(f"No subfolder with name {other!r}")

          def __repr__(self):
              return self.__class__.__name__ + repr(
                  (
                      self.root,
                      self.name,
                      self.total_count,
                      self.unread_count,
                      self.child_folder_count,
                      self.folder_class,
                      self.id,
                      self.changekey,
                  )
              )

          def __str__(self):
              return f"{self.__class__.__name__} ({self.name})"

  ### Ancestors

  - RegisterMixIn
  - IdChangeKeyMixIn
  - EWSElement
  - SearchableMixIn
  - SupportedVersionClassMixIn

  ### Subclasses

  - Folder
  - RootOfHierarchy

  ### Class variables

  `var CONTAINER_CLASS`
  `var DEFAULT_FOLDER_TRAVERSAL_DEPTH`
  `var DEFAULT_ITEM_TRAVERSAL_DEPTH`
  `var DISTINGUISHED_FOLDER_ID`
  `var ELEMENT_NAME`
  `var FIELDS`
  `var ID_ELEMENT_CLS`

    MSDN: https://docs.microsoft.com/en-us/exchange/client-developer/web-service-reference/folderid

  `var INSERT_AFTER_FIELD`
  `var ITEM_MODEL_MAP`
  `var LOCALIZED_NAMES`
  `var NAMESPACE`
  `var get_folder_allowed`
  `var supported_item_models`

  ### Static methods

  `def allowed_item_fields(version)`
    Expand source code

        @classmethod
        def allowed_item_fields(cls, version):
            # Return non-ID fields of all item classes allowed in this folder type
            fields = set()
            for item_model in cls.supported_item_models:
                fields.update(set(item_model.supported_fields(version=version)))
            return fields

  `def folder_cls_from_container_class(container_class)`

    Return a reasonable folder class given a container class, e.g. 'IPF.Note'. Don't iterate WELLKNOWN_FOLDERS because many folder classes have the same CONTAINER_CLASS.

    :param container_class: :return:

    Expand source code

        @staticmethod
        def folder_cls_from_container_class(container_class):
            """Return a reasonable folder class given a container class, e.g. 'IPF.Note'. Don't iterate WELLKNOWN_FOLDERS
            because many folder classes have the same CONTAINER_CLASS.

            :param container_class:
            :return:
            """
            from .known_folders import (
                ApplicationData,
                Calendar,
                Contacts,
                ConversationSettings,
                CrawlerData,
                DlpPolicyEvaluation,
                FreeBusyCache,
                GALContacts,
                Messages,
                RecipientCache,
                RecoveryPoints,
                Reminders,
                RSSFeeds,
                Signal,
                SwssItems,
                Tasks,
            )

            for folder_cls in (
                ApplicationData,
                Calendar,
                Contacts,
                ConversationSettings,
                CrawlerData,
                DlpPolicyEvaluation,
                FreeBusyCache,
                GALContacts,
                Messages,
                RSSFeeds,
                RecipientCache,
                RecoveryPoints,
                Reminders,
                Signal,
                SwssItems,
                Tasks,
            ):
                if folder_cls.CONTAINER_CLASS == container_class:
                    return folder_cls
            raise KeyError()

  `def get_item_field_by_fieldname(fieldname)`
    Expand source code

        @classmethod
        def get_item_field_by_fieldname(cls, fieldname):
            for item_model in cls.supported_item_models:
                with suppress(InvalidField):
                    return item_model.get_field_by_fieldname(fieldname)
            raise InvalidField(f"{fieldname!r} is not a valid field name on {cls.supported_item_models}")

  `def item_model_from_tag(tag)`
    Expand source code

        @classmethod
        def item_model_from_tag(cls, tag):
            try:
                return cls.ITEM_MODEL_MAP[tag]
            except KeyError:
                raise ValueError(f"Item type {tag} was unexpected in a {cls.__name__} folder")

  `def localized_names(locale)`
    Expand source code

        @classmethod
        def localized_names(cls, locale):
            # Return localized names for a specific locale. If no locale-specific names exist, return the default names,
            # if any.
            return tuple(s.lower() for s in cls.LOCALIZED_NAMES.get(locale, cls.LOCALIZED_NAMES.get(None, [])))

  `def resolve(account, folder)`
    Expand source code

        @classmethod
        def resolve(cls, account, folder):
            # Resolve a single folder
            folders = list(FolderCollection(account=account, folders=[folder]).resolve())
            if not folders:
                raise ErrorFolderNotFound(f"Could not find folder {folder!r}")
            if len(folders) != 1:
                raise ValueError(f"Expected result length 1, but got {folders}")
            f = folders[0]
            if isinstance(f, Exception):
                raise f
            if f.__class__ != cls:
                raise ValueError(f"Expected folder {f!r} to be a {cls} instance")
            return f

  ### Instance variables

  `var absolute`
    Expand source code

        @property
        def absolute(self):
            return "".join(f"/{p.name}" for p in self.parts)

  `var account`

    Return the account this folder belongs to

    Expand source code

        @property
        @abc.abstractmethod
        def account(self):
            """Return the account this folder belongs to"""

  `var child_folder_count`
  `var children`
    Expand source code

        @property
        def children(self):
            # It's dangerous to return a generator here because we may then call methods on a child that result in the
            # cache being updated while it's iterated.
            return FolderCollection(account=self.account, folders=self.root.get_children(self))

  `var folder_class`
  `var folder_sync_state`

    Return an attribute of instance, which is of type owner.

  `var has_distinguished_name`
    Expand source code

        @property
        def has_distinguished_name(self):
            return self.name and self.DISTINGUISHED_FOLDER_ID and self.name.lower() == self.DISTINGUISHED_FOLDER_ID.lower()

  `var is_deletable`
    Expand source code

        @property
        def is_deletable(self):
            return not self.is_distinguished

  `var is_distinguished`

    Return an attribute of instance, which is of type owner.

  `var item_sync_state`

    Return an attribute of instance, which is of type owner.

  `var name`
  `var parent`

    Return the parent folder of this folder

    Expand source code

        @property
        @abc.abstractmethod
        def parent(self):
            """Return the parent folder of this folder"""

  `var parent_folder_id`
  `var parts`
    Expand source code

        @property
        def parts(self):
            parts = [self]
            f = self.parent
            while f:
                parts.insert(0, f)
                f = f.parent
            return parts

  `var root`

    Return the root folder this folder belongs to

    Expand source code

        @property
        @abc.abstractmethod
        def root(self):
            """Return the root folder this folder belongs to"""

  `var total_count`
  `var unread_count`

  ### Methods

  `def bulk_create(self, items, *args, **kwargs)`
    Expand source code

        def bulk_create(self, items, *args, **kwargs):
            return self.account.bulk_create(folder=self, items=items, *args, **kwargs)

  `def clean(self, version=None)`
    Expand source code

        def clean(self, version=None):
            super().clean(version=version)
            # Set a default folder class for new folders. A folder class cannot be changed after saving.
            if self.id is None and self.folder_class is None:
                self.folder_class = self.CONTAINER_CLASS

  `def create_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None)`
    Expand source code

        @require_id
        def create_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None):
            from ..services import CreateUserConfiguration

            user_configuration = UserConfiguration(
                user_configuration_name=UserConfigurationName(name=name, folder=self),
                dictionary=dictionary,
                xml_data=xml_data,
                binary_data=binary_data,
            )
            return CreateUserConfiguration(account=self.account).get(user_configuration=user_configuration)

  `def delete(self, delete_type='HardDelete')`
    Expand source code

        def delete(self, delete_type=HARD_DELETE):
            from ..services import DeleteFolder

            DeleteFolder(account=self.account).get(folders=[self], delete_type=delete_type)
            self.root.remove_folder(self)  # Remove the updated folder from the cache
            self._id = None

  `def delete_user_configuration(self, name)`
    Expand source code

        @require_id
        def delete_user_configuration(self, name):
            from ..services import DeleteUserConfiguration

            return DeleteUserConfiguration(account=self.account).get(
                user_configuration_name=UserConfigurationNameMNS(name=name, folder=self)
            )

  `def empty(self, delete_type='HardDelete', delete_sub_folders=False)`
    Expand source code

        def empty(self, delete_type=HARD_DELETE, delete_sub_folders=False):
            from ..services import EmptyFolder

            EmptyFolder(account=self.account).get(
                folders=[self], delete_type=delete_type, delete_sub_folders=delete_sub_folders
            )
            if delete_sub_folders:
                # We don't know exactly what was deleted, so invalidate the entire folder cache to be safe
                self.root.clear_cache()

  `def get_events(self, subscription_id, watermark)`

    Get events since the given watermark. Non-blocking.

    :param subscription_id: A subscription ID as acquired by .subscribe_to_pull|push :param watermark: Either the watermark from the subscription, or as returned by the last .get_events() call. :return: A Notification object containing a list of events

    This method doesn't need the current folder instance, but it makes sense to keep the method along the other sync methods.

    Expand source code

        def get_events(self, subscription_id, watermark):
            """Get events since the given watermark. Non-blocking.

            :param subscription_id: A subscription ID as acquired by .subscribe_to_[pull|push]()
            :param watermark: Either the watermark from the subscription, or as returned by the last .get_events() call.
            :return: A Notification object containing a list of events

            This method doesn't need the current folder instance, but it makes sense to keep the method along the other
            sync methods.
            """
            from ..services import GetEvents

            svc = GetEvents(account=self.account)
            while True:
                notification = svc.get(subscription_id=subscription_id, watermark=watermark)
                yield notification
                if not notification.more_events:
                    break

  `def get_streaming_events(self, subscription_id_or_ids, connection_timeout=1, max_notifications_returned=None)`

    Get events since the subscription was created, in streaming mode. This method will block as many minutes as specified by 'connection_timeout'.

    :param subscription_id_or_ids: A subscription ID, or list of IDs, as acquired by .subscribe_to_streaming() :param connection_timeout: Timeout of the connection, in minutes. The connection is closed after this timeout is reached. :param max_notifications_returned: If specified, will exit after receiving this number of notifications :return: A generator of Notification objects, each containing a list of events

    This method doesn't need the current folder instance, but it makes sense to keep the method along the other sync methods.

    Expand source code

        def get_streaming_events(self, subscription_id_or_ids, connection_timeout=1, max_notifications_returned=None):
            """Get events since the subscription was created, in streaming mode. This method will block as many minutes
            as specified by 'connection_timeout'.

            :param subscription_id_or_ids: A subscription ID, or list of IDs, as acquired by .subscribe_to_streaming()
            :param connection_timeout: Timeout of the connection, in minutes. The connection is closed after this timeout
            is reached.
            :param max_notifications_returned: If specified, will exit after receiving this number of notifications
            :return: A generator of Notification objects, each containing a list of events

            This method doesn't need the current folder instance, but it makes sense to keep the method along the other
            sync methods.
            """
            from ..services import GetStreamingEvents

            svc = GetStreamingEvents(account=self.account)
            subscription_ids = (
                subscription_id_or_ids
                if is_iterable(subscription_id_or_ids, generators_allowed=True)
                else [subscription_id_or_ids]
            )
            for i, notification in enumerate(
                svc.call(subscription_ids=subscription_ids, connection_timeout=connection_timeout), start=1
            ):
                yield notification
                if max_notifications_returned and i >= max_notifications_returned:
                    svc.stop_streaming()
                    break

  `def get_user_configuration(self, name, properties=None)`
    Expand source code

        @require_id
        def get_user_configuration(self, name, properties=None):
            from ..services import GetUserConfiguration
            from ..services.get_user_configuration import ALL

            if properties is None:
                properties = ALL
            return GetUserConfiguration(account=self.account).get(
                user_configuration_name=UserConfigurationNameMNS(name=name, folder=self),
                properties=properties,
            )

  `def glob(self, pattern)`
    Expand source code

        def glob(self, pattern):
            return FolderCollection(account=self.account, folders=self._glob(pattern))

  `def move(self, to_folder)`
    Expand source code

        def move(self, to_folder):
            from ..services import MoveFolder

            res = MoveFolder(account=self.account).get(folders=[self], to_folder=to_folder)
            folder_id, changekey = res.id, res.changekey
            if self.id != folder_id:
                raise ValueError("ID mismatch")
            # Don't check changekey value. It may not change on no-op moves
            self.changekey = changekey
            self.parent_folder_id = ParentFolderId(id=to_folder.id, changekey=to_folder.changekey)
            self.root.update_folder(self)  # Update the folder in the cache

  `def normalize_fields(self, fields)`
    Expand source code

        def normalize_fields(self, fields):
            # Takes a list of fieldnames, Field or FieldPath objects pointing to item fields. Turns them into FieldPath
            # objects and adds internal timezone fields if necessary. Assume fields are already validated.
            fields = list(fields)
            has_start, has_end = False, False
            for i, field_path in enumerate(fields):
                # Allow both Field and FieldPath instances and string field paths as input
                if isinstance(field_path, str):
                    field_path = FieldPath.from_string(field_path=field_path, folder=self)
                    fields[i] = field_path
                elif isinstance(field_path, Field):
                    field_path = FieldPath(field=field_path)
                    fields[i] = field_path
                if field_path.field.name == "start":
                    has_start = True
                elif field_path.field.name == "end":
                    has_end = True

            # For CalendarItem items, we want to inject internal timezone fields. See also CalendarItem.clean()
            if CalendarItem in self.supported_item_models:
                meeting_tz_field, start_tz_field, end_tz_field = CalendarItem.timezone_fields()
                if self.account.version.build < EXCHANGE_2010:
                    if has_start or has_end:
                        fields.append(FieldPath(field=meeting_tz_field))
                else:
                    if has_start:
                        fields.append(FieldPath(field=start_tz_field))
                    if has_end:
                        fields.append(FieldPath(field=end_tz_field))
            return fields

  `def pull_subscription(self, **kwargs)`
    Expand source code

        @require_id
        def pull_subscription(self, **kwargs):
            return PullSubscription(folder=self, **kwargs)

  `def push_subscription(self, **kwargs)`
    Expand source code

        @require_id
        def push_subscription(self, **kwargs):
            return PushSubscription(folder=self, **kwargs)

  `def refresh(self)`
    Expand source code

        @require_id
        def refresh(self):
            fresh_folder = self.resolve(account=self.account, folder=self)
            if self.id != fresh_folder.id:
                raise ValueError("ID mismatch")
            # Apparently, the changekey may get updated
            for f in self.FIELDS:
                setattr(self, f.name, getattr(fresh_folder, f.name))
            return self

  `def save(self, update_fields=None)`
    Expand source code

        def save(self, update_fields=None):
            from ..services import CreateFolder, UpdateFolder

            if self.id is None:
                # New folder
                if update_fields:
                    raise ValueError("'update_fields' is only valid for updates")
                res = CreateFolder(account=self.account).get(parent_folder=self.parent, folders=[self])
                self._id = self.ID_ELEMENT_CLS(res.id, res.changekey)
                self.root.add_folder(self)  # Add this folder to the cache
                return self

            # Update folder
            if not update_fields:
                # The fields to update was not specified explicitly. Update all fields where update is possible
                update_fields = []
                for f in self.supported_fields(version=self.account.version):
                    if f.is_read_only:
                        # These cannot be changed
                        continue
                    if (f.is_required or f.is_required_after_save) and (
                        getattr(self, f.name) is None or (f.is_list and not getattr(self, f.name))
                    ):
                        # These are required and cannot be deleted
                        continue
                    update_fields.append(f.name)
            res = UpdateFolder(account=self.account).get(folders=[(self, update_fields)])
            folder_id, changekey = res.id, res.changekey
            if self.id != folder_id:
                raise ValueError("ID mismatch")
            # Don't check changekey value. It may not change on no-op updates
            self.changekey = changekey
            self.root.update_folder(self)  # Update the folder in the cache
            return self

  `def streaming_subscription(self, **kwargs)`
    Expand source code

        @require_id
        def streaming_subscription(self, **kwargs):
            return StreamingSubscription(folder=self, **kwargs)

  `def subscribe_to_pull(self, event_types=None, watermark=None, timeout=60)`

    Create a pull subscription.

    :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPull.EVENT_TYPES :param watermark: An event bookmark as returned by some sync services :param timeout: Timeout of the subscription, in minutes. Timeout is reset when the server receives a GetEvents request for this subscription. :return: The subscription ID and a watermark

    Expand source code

        @require_id
        def subscribe_to_pull(self, event_types=None, watermark=None, timeout=60):
            """Create a pull subscription.

            :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPull.EVENT_TYPES
            :param watermark: An event bookmark as returned by some sync services
            :param timeout: Timeout of the subscription, in minutes. Timeout is reset when the server receives a
            GetEvents request for this subscription.
            :return: The subscription ID and a watermark
            """
            from ..services import SubscribeToPull

            if event_types is None:
                event_types = SubscribeToPull.EVENT_TYPES
            return FolderCollection(account=self.account, folders=[self]).subscribe_to_pull(
                event_types=event_types,
                watermark=watermark,
                timeout=timeout,
            )

  `def subscribe_to_push(self, callback_url, event_types=None, watermark=None, status_frequency=1)`

    Create a push subscription.

    :param callback_url: A client-defined URL that the server will call :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES :param watermark: An event bookmark as returned by some sync services :param status_frequency: The frequency, in minutes, that the callback URL will be called with. :return: The subscription ID and a watermark

    Expand source code

        @require_id
        def subscribe_to_push(self, callback_url, event_types=None, watermark=None, status_frequency=1):
            """Create a push subscription.

            :param callback_url: A client-defined URL that the server will call
            :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES
            :param watermark: An event bookmark as returned by some sync services
            :param status_frequency: The frequency, in minutes, that the callback URL will be called with.
            :return: The subscription ID and a watermark
            """
            from ..services import SubscribeToPush

            if event_types is None:
                event_types = SubscribeToPush.EVENT_TYPES
            return FolderCollection(account=self.account, folders=[self]).subscribe_to_push(
                event_types=event_types,
                watermark=watermark,
                status_frequency=status_frequency,
                callback_url=callback_url,
            )

  `def subscribe_to_streaming(self, event_types=None)`

    Create a streaming subscription.

    :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES :return: The subscription ID

    Expand source code

        @require_id
        def subscribe_to_streaming(self, event_types=None):
            """Create a streaming subscription.

            :param event_types: List of event types to subscribe to. Possible values defined in SubscribeToPush.EVENT_TYPES
            :return: The subscription ID
            """
            from ..services import SubscribeToStreaming

            if event_types is None:
                event_types = SubscribeToStreaming.EVENT_TYPES
            return FolderCollection(account=self.account, folders=[self]).subscribe_to_streaming(event_types=event_types)

  `def sync_hierarchy(self, sync_state=None, only_fields=None)`

    Return all folder changes to a folder hierarchy, as a generator. If sync_state is specified, get all folder changes after this sync state. After fully consuming the generator, self.folder_sync_state will hold the new sync state.

    :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service. :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields :return:

    Expand source code

        def sync_hierarchy(self, sync_state=None, only_fields=None):
            """Return all folder changes to a folder hierarchy, as a generator. If sync_state is specified, get all folder
            changes after this sync state. After fully consuming the generator, self.folder_sync_state will hold the new
            sync state.

            :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service.
            :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields
            :return:
            """
            if not sync_state:
                sync_state = self.folder_sync_state
            try:
                yield from FolderCollection(account=self.account, folders=[self]).sync_hierarchy(
                    sync_state=sync_state,
                    only_fields=only_fields,
                )
            except SyncCompleted as e:
                # Set the new sync state on the folder instance
                self.folder_sync_state = e.sync_state

  `def sync_items(self, sync_state=None, only_fields=None, ignore=None, max_changes_returned=None, sync_scope=None)`

    Return all item changes to a folder, as a generator. If sync_state is specified, get all item changes after this sync state. After fully consuming the generator, self.item_sync_state will hold the new sync state.

    :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service. :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields :param ignore: A list of Item IDs to ignore in the sync :param max_changes_returned: The max number of change :param sync_scope: Specify whether to return just items, or items and folder associated information. Possible values are specified in SyncFolderItems.SYNC_SCOPES :return: A generator of (change_type, item) tuples

    Expand source code

        def sync_items(self, sync_state=None, only_fields=None, ignore=None, max_changes_returned=None, sync_scope=None):
            """Return all item changes to a folder, as a generator. If sync_state is specified, get all item changes after
            this sync state. After fully consuming the generator, self.item_sync_state will hold the new sync state.

            :param sync_state: The state of the sync. Returned by a successful call to the SyncFolderItems service.
            :param only_fields: A list of string or FieldPath items specifying the fields to fetch. Default to all fields
            :param ignore: A list of Item IDs to ignore in the sync
            :param max_changes_returned: The max number of change
            :param sync_scope: Specify whether to return just items, or items and folder associated information. Possible
               values are specified in SyncFolderItems.SYNC_SCOPES
            :return: A generator of (change_type, item) tuples
            """
            if not sync_state:
                sync_state = self.item_sync_state
            try:
                yield from FolderCollection(account=self.account, folders=[self]).sync_items(
                    sync_state=sync_state,
                    only_fields=only_fields,
                    ignore=ignore,
                    max_changes_returned=max_changes_returned,
                    sync_scope=sync_scope,
                )
            except SyncCompleted as e:
                # Set the new sync state on the folder instance
                self.item_sync_state = e.sync_state

  `def test_access(self)`

    Does a simple FindItem to test (read) access to the folder. Maybe the account doesn't exist, maybe the service user doesn't have access to the calendar. This will throw the most common errors.

    Expand source code

        def test_access(self):
            """Does a simple FindItem to test (read) access to the folder. Maybe the account doesn't exist, maybe the
            service user doesn't have access to the calendar. This will throw the most common errors.
            """
            self.all().exists()
            return True

  `def to_id(self)`
    Expand source code

        def to_id(self):
            if self.is_distinguished:
                # Don't add the changekey here. When modifying folder content, we usually don't care if others have changed
                # the folder content since we fetched the changekey.
                if self.account:
                    return DistinguishedFolderId(
                        id=self.DISTINGUISHED_FOLDER_ID, mailbox=Mailbox(email_address=self.account.primary_smtp_address)
                    )
                return DistinguishedFolderId(id=self.DISTINGUISHED_FOLDER_ID)
            if self.id:
                return FolderId(id=self.id, changekey=self.changekey)
            raise ValueError("Must be a distinguished folder or have an ID")

  `def tree(self)`

    Return a string representation of the folder structure of this folder. Example:

    root ├── inbox │ └── todos └── archive ├── Last Job ├── exchangelib issues └── Mom

    Expand source code

        def tree(self):
            """Return a string representation of the folder structure of this folder. Example:

            root
            ├── inbox
            │   └── todos
            └── archive
                ├── Last Job
                ├── exchangelib issues
                └── Mom
            """
            tree = f"{self.name}\n"
            children = list(self.children)
            for i, c in enumerate(sorted(children, key=attrgetter("name")), start=1):
                nodes = c.tree().split("\n")
                for j, node in enumerate(nodes, start=1):
                    if i != len(children) and j == 1:
                        # Not the last child, but the first node, which is the name of the child
                        tree += f"├── {node}\n"
                    elif i != len(children) and j > 1:
                        # Not the last child, and not name of child
                        tree += f"│   {node}\n"
                    elif i == len(children) and j == 1:
                        # Not the last child, but the first node, which is the name of the child
                        tree += f"└── {node}\n"
                    else:  # Last child and not name of child
                        tree += f"    {node}\n"
            return tree.strip()

  `def unsubscribe(self, subscription_id)`

    Unsubscribe. Only applies to pull and streaming notifications.

    :param subscription_id: A subscription ID as acquired by .subscribe_to_pull|streaming :return: True

    This method doesn't need the current folder instance, but it makes sense to keep the method along the other sync methods.

    Expand source code

        def unsubscribe(self, subscription_id):
            """Unsubscribe. Only applies to pull and streaming notifications.

            :param subscription_id: A subscription ID as acquired by .subscribe_to_[pull|streaming]()
            :return: True

            This method doesn't need the current folder instance, but it makes sense to keep the method along the other
            sync methods.
            """
            from ..services import Unsubscribe

            return Unsubscribe(account=self.account).get(subscription_id=subscription_id)

  `def update_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None)`
    Expand source code

        @require_id
        def update_user_configuration(self, name, dictionary=None, xml_data=None, binary_data=None):
            from ..services import UpdateUserConfiguration

            user_configuration = UserConfiguration(
                user_configuration_name=UserConfigurationName(name=name, folder=self),
                dictionary=dictionary,
                xml_data=xml_data,
                binary_data=binary_data,
            )
            return UpdateUserConfiguration(account=self.account).get(user_configuration=user_configuration)

  `def validate_item_field(self, field, version)`
    Expand source code

        def validate_item_field(self, field, version):
            FolderCollection(account=self.account, folders=[self]).validate_item_field(field=field, version=version)

  `def walk(self)`
    Expand source code

        def walk(self):
            return FolderCollection(account=self.account, folders=self._walk())

  `def wipe(self, page_size=None, chunk_size=None)`
    Expand source code

        def wipe(self, page_size=None, chunk_size=None, _seen=None, _level=0):
            # Recursively deletes all items in this folder, and all sub-folders and their content. Attempts to protect
            # distinguished folders from being deleted. Use with caution!
            from .known_folders import Audits

            _seen = _seen or set()
            if self.id in _seen:
                raise RecursionError(f"We already tried to wipe {self}")
            if _level > 16:
                raise RecursionError(f"Max recursion level reached: {_level}")
            _seen.add(self.id)
            if isinstance(self, Audits):
                # Shortcircuit because this folder can have many items that are all non-deletable
                log.warning("Cannot wipe audits folder %s", self)
                return
            if self.is_distinguished and "recoverableitems" in self.DISTINGUISHED_FOLDER_ID:
                log.warning("Cannot wipe recoverable items folder %s", self)
                return
            log.warning("Wiping %s", self)
            has_distinguished_subfolders = any(f.is_distinguished for f in self.children)
            try:
                if has_distinguished_subfolders:
                    self.empty()
                else:
                    self.empty(delete_sub_folders=True)
            except ErrorRecoverableItemsAccessDenied:
                log.warning("Access denied to %s. Skipping", self)
                return
            except DELETE_FOLDER_ERRORS:
                try:
                    if has_distinguished_subfolders:
                        raise  # We already tried this
                    self.empty()
                except DELETE_FOLDER_ERRORS:
                    log.warning("Not allowed to empty %s. Trying to delete items instead", self)
                    kwargs = {}
                    if page_size is not None:
                        kwargs["page_size"] = page_size
                    if chunk_size is not None:
                        kwargs["chunk_size"] = chunk_size
                    try:
                        self.all().delete(**kwargs)
                    except DELETE_FOLDER_ERRORS:
                        log.warning("Not allowed to delete items in %s", self)
            _level += 1
            for f in self.children:
                f.wipe(page_size=page_size, chunk_size=chunk_size, _seen=_seen, _level=_level)
                # Remove non-distinguished children that are empty and have no sub-folders
                if f.is_deletable and not f.children:
                    log.warning("Deleting folder %s", f)
                    try:
                        f.delete()
                    except ErrorDeleteDistinguishedFolder:
                        log.warning("Tried to delete a distinguished folder (%s)", f)

  ### Inherited members

  - `RegisterMixIn`:
    - `add_field`
    - `deregister`
    - `register`
    - `remove_field`
    - `supported_fields`
    - `validate_field`
  - `SearchableMixIn`:
    - `all`
    - `exclude`
    - `filter`
    - `get`
    - `none`
    - `people`
`class Folder (**kwargs)`

  MSDN: https://docs.microsoft.com/en-us/exchange/client-developer/web-service-reference/folder

  Expand source code

      class Folder(BaseFolder):
          """MSDN: https://docs.microsoft.com/en-us/exchange/client-developer/web-service-reference/folder"""

          permission_set = PermissionSetField(field_uri="folder:PermissionSet", supported_from=EXCHANGE_2007_SP1)
          effective_rights = EffectiveRightsField(
              field_uri="folder:EffectiveRights", is_read_only=True, supported_from=EXCHANGE_2007_SP1
          )

          __slots__ = ("_root",)

          def __init__(self, **kwargs):
              self._root = kwargs.pop("root", None)  # This is a pointer to the root of the folder hierarchy
              parent = kwargs.pop("parent", None)
              if parent:
                  if self.root:
                      if parent.root != self.root:
                          raise ValueError("'parent.root' must match 'root'")
                  else:
                      self.root = parent.root
                  if "parent_folder_id" in kwargs and parent.id != kwargs["parent_folder_id"]:
                      raise ValueError("'parent_folder_id' must match 'parent' ID")
                  kwargs["parent_folder_id"] = ParentFolderId(id=parent.id, changekey=parent.changekey)
              super().__init__(**kwargs)

          @property
          def account(self):
              if self.root is None:
                  return None
              return self.root.account

          @property
          def root(self):
              return self._root

          @root.setter
          def root(self, value):
              self._root = value

          @classmethod
          def register(cls, *args, **kwargs):
              if cls is not Folder:
                  raise TypeError("For folders, custom fields must be registered on the Folder class")
              return super().register(*args, **kwargs)

          @classmethod
          def deregister(cls, *args, **kwargs):
              if cls is not Folder:
                  raise TypeError("For folders, custom fields must be registered on the Folder class")
              return super().deregister(*args, **kwargs)

          @classmethod
          def get_distinguished(cls, root):
              """Get the distinguished folder for this folder class.

              :param root:
              :return:
              """
              try:
                  return cls.resolve(
                      account=root.account, folder=cls(root=root, name=cls.DISTINGUISHED_FOLDER_ID, is_distinguished=True)
                  )
              except MISSING_FOLDER_ERRORS:
                  raise ErrorFolderNotFound(f"Could not find distinguished folder {cls.DISTINGUISHED_FOLDER_ID!r}")

          @property
          def parent(self):
              if not self.parent_folder_id:
                  return None
              if self.parent_folder_id.id == self.id:
                  # Some folders have a parent that references itself. Avoid circular references here
                  return None
              return self.root.get_folder(self.parent_folder_id)

          @parent.setter
          def parent(self, value):
              if value is None:
                  self.parent_folder_id = None
              else:
                  if not isinstance(value, BaseFolder):
                      raise InvalidTypeError("value", value, BaseFolder)
                  self.root = value.root
                  self.parent_folder_id = ParentFolderId(id=value.id, changekey=value.changekey)

          def clean(self, version=None):
              from .roots import RootOfHierarchy

              super().clean(version=version)
              if self.root and not isinstance(self.root, RootOfHierarchy):
                  raise InvalidTypeError("root", self.root, RootOfHierarchy)

          @classmethod
          def from_xml_with_root(cls, elem, root):
              folder = cls.from_xml(elem=elem, account=root.account)
              folder_cls = cls
              if cls == Folder:
                  # We were called on the generic Folder class. Try to find a more specific class to return objects as.
                  #
                  # The "FolderClass" element value is the only indication we have in the FindFolder response of which
                  # folder class we should create the folder with. And many folders share the same 'FolderClass' value, e.g.
                  # Inbox and DeletedItems. We want to distinguish between these because otherwise we can't locate the right
                  # folders types for e.g. Account.inbox and Account.trash.
                  #
                  # We should be able to just use the name, but apparently default folder names can be renamed to a set of
                  # localized names using a PowerShell command:
                  # https://docs.microsoft.com/en-us/powershell/module/exchange/client-access/Set-MailboxRegionalConfiguration
                  #
                  # Instead, search for a folder class using the localized name. If none are found, fall back to getting the
                  # folder class by the "FolderClass" value.
                  #
                  # The returned XML may contain neither folder class nor name. In that case, we default to the generic
                  # Folder class.
                  if folder.name:
                      with suppress(KeyError):
                          # TODO: fld_class.LOCALIZED_NAMES is most definitely neither complete nor authoritative
                          folder_cls = root.folder_cls_from_folder_name(folder_name=folder.name, locale=root.account.locale)
                          log.debug("Folder class %s matches localized folder name %s", folder_cls, folder.name)
                  if folder.folder_class and folder_cls == Folder:
                      with suppress(KeyError):
                          folder_cls = cls.folder_cls_from_container_class(container_class=folder.folder_class)
                          log.debug(
                              "Folder class %s matches container class %s (%s)", folder_cls, folder.folder_class, folder.name
                          )
                  if folder_cls == Folder:
                      log.debug("Fallback to class Folder (folder_class %s, name %s)", folder.folder_class, folder.name)
              return folder_cls(root=root, **{f.name: getattr(folder, f.name) for f in folder.FIELDS})

  ### Ancestors

  - BaseFolder
  - RegisterMixIn
  - IdChangeKeyMixIn
  - EWSElement
  - SearchableMixIn
  - SupportedVersionClassMixIn

  ### Subclasses

  - AllItems
  - ApplicationData
  - Audits
  - Birthdays
  - Calendar
  - CalendarLogging
  - CommonViews
  - Contacts
  - ConversationSettings
  - CrawlerData
  - DefaultFoldersChangeHistory
  - DeferredAction
  - DeletedItems
  - DlpPolicyEvaluation
  - ExchangeSyncData
  - Files
  - FreeBusyCache
  - FreebusyData
  - GraphAnalytics
  - Location
  - MailboxAssociations
  - Messages
  - ParkedMessages
  - PassThroughSearchResults
  - PdpProfileV2Secured
  - RSSFeeds
  - RecoveryPoints
  - Reminders
  - Schedule
  - Sharing
  - Shortcuts
  - Signal
  - SkypeTeamsMessages
  - SmsAndChatsSync
  - SpoolerQueue
  - SwssItems
  - System
  - System1
  - Tasks
  - TemporarySaves
  - Views
  - WellknownFolder
  - WorkingSet

  ### Class variables

  `var FIELDS`

  ### Static methods

  `def from_xml_with_root(elem, root)`
    Expand source code

        @classmethod
        def from_xml_with_root(cls, elem, root):
            folder = cls.from_xml(elem=elem, account=root.account)
            folder_cls = cls
            if cls == Folder:
                # We were called on the generic Folder class. Try to find a more specific class to return objects as.
                #
                # The "FolderClass" element value is the only indication we have in the FindFolder response of which
                # folder class we should create the folder with. And many folders share the same 'FolderClass' value, e.g.
                # Inbox and DeletedItems. We want to distinguish between these because otherwise we can't locate the right
                # folders types for e.g. Account.inbox and Account.trash.
                #
                # We should be able to just use the name, but apparently default folder names can be renamed to a set of
                # localized names using a PowerShell command:
                # https://docs.microsoft.com/en-us/powershell/module/exchange/client-access/Set-MailboxRegionalConfiguration
                #
                # Instead, search for a folder class using the localized name. If none are found, fall back to getting the
                # folder class by the "FolderClass" value.
                #
                # The returned XML may contain neither folder class nor name. In that case, we default to the generic
                # Folder class.
                if folder.name:
                    with suppress(KeyError):
                        # TODO: fld_class.LOCALIZED_NAMES is most definitely neither complete nor authoritative
                        folder_cls = root.folder_cls_from_folder_name(folder_name=folder.name, locale=root.account.locale)
                        log.debug("Folder class %s matches localized folder name %s", folder_cls, folder.name)
                if folder.folder_class and folder_cls == Folder:
                    with suppress(KeyError):
                        folder_cls = cls.folder_cls_from_container_class(container_class=folder.folder_class)
                        log.debug(
                            "Folder class %s matches container class %s (%s)", folder_cls, folder.folder_class, folder.name
                        )
                if folder_cls == Folder:
                    log.debug("Fallback to class Folder (folder_class %s, name %s)", folder.folder_class, folder.name)
            return folder_cls(root=root, **{f.name: getattr(folder, f.name) for f in folder.FIELDS})

  `def get_distinguished(root)`

    Get the distinguished folder for this folder class.

    :param root: :return:

    Expand source code

        @classmethod
        def get_distinguished(cls, root):
            """Get the distinguished folder for this folder class.

            :param root:
            :return:
            """
            try:
                return cls.resolve(
                    account=root.account, folder=cls(root=root, name=cls.DISTINGUISHED_FOLDER_ID, is_distinguished=True)
                )
            except MISSING_FOLDER_ERRORS:
                raise ErrorFolderNotFound(f"Could not find distinguished folder {cls.DISTINGUISHED_FOLDER_ID!r}")

  ### Instance variables

  `var effective_rights`
  `var permission_set`

  ### Methods

  `def clean(self, version=None)`
    Expand source code

        def clean(self, version=None):
            from .roots import RootOfHierarchy

            super().clean(version=version)
            if self.root and not isinstance(self.root, RootOfHierarchy):
                raise InvalidTypeError("root", self.root, RootOfHierarchy)

  ### Inherited members

  - `BaseFolder`:
    - `ID_ELEMENT_CLS`
    - `account`
    - `add_field`
    - `all`
    - `deregister`
    - `exclude`
    - `filter`
    - `folder_cls_from_container_class`
    - `folder_sync_state`
    - `get`
    - `get_events`
    - `get_streaming_events`
    - `is_distinguished`
    - `item_sync_state`
    - `none`
    - `parent`
    - `people`
    - `register`
    - `remove_field`
    - `root`
    - `subscribe_to_pull`
    - `subscribe_to_push`
    - `subscribe_to_streaming`
    - `supported_fields`
    - `sync_hierarchy`
    - `sync_items`
    - `test_access`
    - `tree`
    - `unsubscribe`
    - `validate_field`