urlwatch(1) [debian man page]

URLWATCH(1)							   User Commands						       URLWATCH(1)

NAME

       urlwatch - Watch web pages and arbitrary URLs for changes

SYNOPSIS

       urlwatch [options]

DESCRIPTION

       urlwatch  watches  a list of URLs for changes and prints out unified diffs of the changes. You can filter always-changing parts of websites
       by providing a "hooks.py" script.

OPTIONS

       --version
	      show program's version number and exit

       -h, --help
	      show the help message and exit

       -v, --verbose
	      Show debug/log output

       --urls=FILE
	      Read URLs from the specified file

       --hooks=FILE
	      Use specified file as hooks.py module

       -e, --display-errors
	      Include HTTP errors (404, etc..) in the output

ADVANCED FEATURES

       urlwatch includes some advanced features that you have to activate by creating a hooks.py file that specifies for which URLs to use a  spe-
       cific feature. You can also use the hooks.py file to filter trivially-varying elements of a web page.

   ICALENDAR FILE PARSING
       This  module allows you to parse .ics files that are in iCalendar format and provide a very simplified text-based format for the diffs. Use
       it like this in your hooks.py file:

	 from urlwatch import ical2txt

	 def filter(url, data):
	     if url.endswith('.ics'):
		 return ical2txt.ical2text(data).encode('utf-8') + data
	     # ...you can add more hooks here...

   HTML TO TEXT CONVERSION
       There are three methods of converting HTML to text in the current version of urlwatch: "lynx" (default), "html2text" and "re".  The  former
       two  use  command-line  utilities of the same name to convert HTML to text, and the last one uses a simple regex-based tag stripping method
       (needs no extra tools).	Here is an example of using it in your hooks.py file:

	 from urlwatch import html2txt

	 def filter(url, data):
	     if url.endswith('.html') or url.endswith('.htm'):
		 return html2txt.html2text(data, method='lynx')
	     # ...you can add more hooks here...

FILES

       ~/.urlwatch/urls.txt
	      A list of HTTP/FTP URLs to watch (one URL per line)

       ~/.urlwatch/lib/hooks.py
	      A Python module that can be used to filter contents

       ~/.urlwatch/cache/
	      The state of web pages is saved in this folder

AUTHOR

       Thomas Perl <thp@thpinfo.com>

WEBSITE

       http://thpinfo.com/2008/urlwatch/

urlwatch 1.11							     July 2010							       URLWATCH(1)

HTML::LinkExtor(3)					User Contributed Perl Documentation					HTML::LinkExtor(3)

NAME

       HTML::LinkExtor - Extract links from an HTML document

SYNOPSIS

	require HTML::LinkExtor;
	$p = HTML::LinkExtor->new(&cb, "http://www.perl.org/");
	sub cb {
	    my($tag, %links) = @_;
	    print "$tag @{[%links]}
";
	}
	$p->parse_file("index.html");

DESCRIPTION

       HTML::LinkExtor is an HTML parser that extracts links from an HTML document.  The HTML::LinkExtor is a subclass of HTML::Parser. This means
       that the document should be given to the parser by calling the $p->parse() or $p->parse_file() methods.

       $p = HTML::LinkExtor->new
       $p = HTML::LinkExtor->new( $callback )
       $p = HTML::LinkExtor->new( $callback, $base )
	   The constructor takes two optional arguments. The first is a reference to a callback routine. It will be called as links are found. If
	   a callback is not provided, then links are just accumulated internally and can be retrieved by calling the $p->links() method.

	   The $base argument is an optional base URL used to absolutize all URLs found.  You need to have the URI module installed if you provide
	   $base.

	   The callback is called with the lowercase tag name as first argument, and then all link attributes as separate key/value pairs.  All
	   non-link attributes are removed.

       $p->links
	   Returns a list of all links found in the document.  The returned values will be anonymous arrays with the following elements:

	     [$tag, $attr => $url1, $attr2 => $url2,...]

	   The $p->links method will also truncate the internal link list.  This means that if the method is called twice without any parsing
	   between them the second call will return an empty list.

	   Also note that $p->links will always be empty if a callback routine was provided when the HTML::LinkExtor was created.

EXAMPLE

       This is an example showing how you can extract links from a document received using LWP:

	 use LWP::UserAgent;
	 use HTML::LinkExtor;
	 use URI::URL;

	 $url = "http://www.perl.org/";  # for instance
	 $ua = LWP::UserAgent->new;

	 # Set up a callback that collect image links
	 my @imgs = ();
	 sub callback {
	    my($tag, %attr) = @_;
	    return if $tag ne 'img';  # we only look closer at <img ...>
	    push(@imgs, values %attr);
	 }

	 # Make the parser.  Unfortunately, we don't know the base yet
	 # (it might be different from $url)
	 $p = HTML::LinkExtor->new(&callback);

	 # Request document and parse it as it arrives
	 $res = $ua->request(HTTP::Request->new(GET => $url),
			     sub {$p->parse($_[0])});

	 # Expand all image URLs to absolute ones
	 my $base = $res->base;
	 @imgs = map { $_ = url($_, $base)->abs; } @imgs;

	 # Print them out
	 print join("
", @imgs), "
";

SEE ALSO

       HTML::Parser, HTML::Tagset, LWP, URI::URL

COPYRIGHT

       Copyright 1996-2001 Gisle Aas.

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

perl v5.18.2							    2013-03-25							HTML::LinkExtor(3)