HTML::TagReader
---------------
Summary:
TagReader is a perl extension module which allows you to read html/xml
files by tag. That is: in a similar way as you can read textfiles by
line with "while(<>)" you use TagReader::getbytoken to read a file by tag.
You find a complete description of HTML::TagReader further down.

Installation:
To install run:
perl Makefile.PL
make
make test
make install
------------------- ------------------- -------------------
Non-standard Installation:

If you want to install TagReader and the application programs
below /usr/local (/usr/local/bin , /usr/local/lib/5.6.0/i386-linux 
/usr/local/lib/site_perl/5.6.0/i386-linux/auto/HTML/TagReader etc...) 
then run
perl Makefile.PL PREFIX=/usr/local
make
make test
make install

To install only the perl module in a different location
(but e.g. the man pages in the standard location) use:

perl Makefile.PL LIB=/you/new/libpath
make test
make install

------------------- ------------------- -------------------
The subdirectory bin contains 4 applications of TagReader.
All of them start with the prefix "tr_"
tr_blck -- check for broken relative links in html pages
tr_llnk -- list links in html files
tr_xlnk -- expand links on directories
tr_mvlnk -- modify tags in html files with perl commands.
tr_staticssi -- expand SSI directives #include virtual and #exec cmd

tr_httpcheck -- check if a particular web-pages exists
             httpcheck does not directyl use the TagReader module
             but may be used as post processor for blck   
             If you are interessted in a link checker to check
             links only via the web-server then this is not the
             right program for you. Other programs like e.g 

              http://linkchecker.sourceforge.net/ or
	      http://www.linklint.org/ or
              http://linkchecker.stacken.kth.se/ (webpage where
              you can enter a url to check) or
	      http://htcheck.sourceforge.net/ or
	      http://www.jmarshall.com/tools/cl/

             can be used if you want to check your web-pages only 
             remotely via a web server. 

tr_tagcontentgrep -- grep for a tag e.g "img src" 

Note the primary desing goal of TagReader is to provide a fast
way of reading/processing html files. 

These application programs will normally be installed to /usr/bin/

------------------- ------------------- -------------------
Author: guido(at)linuxfocus.org

Homepage: http://linuxfocus.org/~guido/
Homepage on CPAN: http://cpan.org/authors/id/G/GU/GUS/

Copyright:  This program is free software; you can redistribute it 
and/or modify it under the same terms as Perl itself.

Installation requirements: Perl and a c-compiler (e.g gcc)
------------------- ------------------- -------------------
NAME
    TagReader - Perl extension module for reading html/sgml/xml files by
    tags.

SYNOPSIS
      use HTML::TagReader;
      # open then file and get an obj-ref:
      my $p=new HTML::TagReader "filename";

      # set to zero or undef to omit warnings about html error:
      $showerrors=1; 

      # get only the tags:
      my $tag = $p->gettag($showerrors);
        # or
      my ($tag,$linenumber) = $p->gettag($showerrors);

      # get the entire file split into tags and text parts:
      my $tag = $p->getbytoken($showerrors);
        # or
      my ($tag,$tagtype,$linenumber) = $p->getbytoken($showerrors);

DESCRIPTION
    The module implements a fast and small object oriented way of processing
    any kind of html/sgml/xml files by tag.

    The getbytoken(0) is similar to while(<>) but instead of reading lines
    it reads tags or tags and text.

    HTML::TagReader makes it easy to keep track of the line number in a file
    even though you are not reading the file by line. This important if you
    want to implement error messages about html error in your code.

    Here is a program that list all href tags in a html file together with
    it line numbers:

            use TagReader;
            my $p=new TagReader "file.html";
            my @tag;
            while(@tag = $p->gettag(1)){
                    if ($tag[0]=~/ href ?=/i){
                            # remove optional space before the equal sign:
                            $tag[0]=~s/ ?= ?/=/g;
                            print "line: $tag[1]: $tag[0]\n";
                    }
            }

    Here is a program that will read a html file tag wise:

            use TagReader;
            my $p=new TagReader "file.html";
            my @tag;
            while(@tag = $p->getbytoken(1)){
                    if ($tag[1] eq ""){
                            print "line: $tag[2]: not a tag (some text), \"$tag[0]\"\n\n";
                    }else{
                            print "line: $tag[2]: is a tag, $tag[0]\n\n";
                    }
            }

  new HTML::TagReader $file;

    Returns a reference to a TagReader object. This reference can be used
    with gettag() or getbytoken() to read the next tag.

  gettag($showerrors);

    Returns in an array context tag and line number. In a scalar context
    just the next tag.

    An empty string or and empty array is returned if the file contains no
    further tags. html/xml comments and any tags inside the comments are
    ignored.

    The returned tag string has all white space (tab, newline...) reduced to
    just a single space otherwise upper and lower case, quotes etc are as in
    the original file. The line numbers are those where the tag starts.

    You must provide 0 (or undef) or 1 as an argument to gettag. If 0 is
    provided then gettag will not print any errors if it finds a syntax
    error in the html/sgml/xml code.

    Currently only the following warning messages are implemented to warn
    about possible html syntax errors:

    - A starting '<' was found but no closing '>' after 300 characters

    - A single '<' was found which was not followed by [!/a-zA-Z]. Such a
    '<' should be written as &lt;

    - A single '>' was found outside a tag.

  getbytoken($showerrors);

    Returns in an array context tag, tagtype (a, br, img,...) and line
    number. In a scalar context just the next tag.

    An empty string or and empty array is returned if the file contains no
    further tags.

    getbytoken() should be used to process a html file and possibly modify
    tags. As opposed to gettag() the getbytoken() does not remove newline or
    space from the data. getbytoken() gives you access to the entire file
    and not only to the tags. That is: you can process the tags and the text
    between the tags.

    tagtype is always lower case. The tagtype is the string starting the tag
    such as "a" in <a href=""> or "!--" in <!-- comment -->. tagtype is
    empty if this is not a tag (normal text or newline).

    You must provide 0 (or undef) or 1 as an argument to getbytoken. If 0 is
    provided then gettag will not print any errors if it finds a syntax
    error in the html/sgml/xml code.

    Currently only the following warning messages are implemented to warn
    about possible html syntax errors:

    - A starting '<' was found but no closing '>' after 300 characters

    - A single '<' was found which was not followed by [!/a-zA-Z]. Such a
    '<' should be written as &lt;

    - A single '>' was found outside a tag.

  Working without HTML::TagReader

    In special cases it is possible to do processing of files by tag in an
    efficient way without the HTML::TagReader package. This can be done by
    setting the record separator variable in perl ($/). This causes however
    problems with faulty html code where individual '<'-characters appear in
    the middle of the text. An example of such a program written in plain
    perl (without HTML::TagReader) is the tr_tagcontentgrep program which is
    part of the HTML::TagReader distribution. Think first then write your
    code! (HTML::TagReader is in most cases the best choice, not in all ;-)

  Limitations

    There are no limitation to the size of the file.

    If you need a more sophisticated interface you might want to take a look
    at HTML::Parser. HTML:TagReader is fast generic and straight forward to
    use.

COPYRIGHT
    Copyright (c) Guido Socher [guido(at)linuxfocus.org]

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

SEE ALSO
    homepage of this program: http://linuxfocus.org/~guido/ or
    http://cpan.org/authors/id/G/GU/GUS/

    perl(1) HTML::Parser(3)

