Alex Efros > CGI-Easy-URLconf > CGI::Easy::URLconf



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Module Version: v2.0.0   Source  


CGI::Easy::URLconf - map url path to handler sub and vice versa


This document describes CGI::Easy::URLconf version v2.0.0


    use CGI::Easy::URLconf qw( setup_path path2view set_param );

        '/about/'               => \&myabout,
        '/terms.php'            => \&terms,
        qr{\A /articles/ \z}xms => \&list_all_articles,
        qr{\A /articles/(\d+)/ \z}xms
            => set_param('year')
            => \&list_articles,
        qr{\A /articles/tag/(\w+)/(\d+)/ \z}xms
            => set_param('tag','year')
            => \&list_articles,
    setup_path( POST =>
        '/articles/'            => \&add_article,

    my $r = CGI::Easy::Request->new();
    my $handler = path2view($r);

    use CGI::Easy::URLconf qw( setup_view view2path with_params );

        \&list_all_articles     => '/articles/',
        \&list_articles         => [
            with_params('tag','year')   => '/articles/tag/?/?/',
            with_params('year')         => '/articles/?/',

    # set $url to '/about/'
    my $url = view2path( \&myabout );

    # set $url to '/articles/'
    my $url = view2path( \&list_all_articles );

    # set $url to '/articles/2010/?month=12'
    my $url = view2path( \&list_articles, year=>2010, month=>12 );


This module provide support for clean, user-friendly URLs. This can be archived by configuring web server to run your CGI/FastCGI script for any url requested by user, and let you manually dispatch different urls to corresponding handlers (subroutines). Additionally, you can take some CGI parameters from url's path instead of usual GET parameters.

 The idea is to set rules when CGI/FastCGI starts using:
   a) setup_path() - to map url's path to handler subroutine
      (also called "view")
   b) setup_view() - to map handler subroutine to url
 and then use:
   a) path2view() - to get handler subroutine matching current url's path
   b) view2path() - to get url matching some handler subroutine
      (for inserting into HTML templates or sending redirects).


    # -- while CGI/FastCGI initialization
        '/articles/'        => \&list_articles,
        '/articles.php'     => \&list_articles,
        '/index.php'        => \&show_home_page,
    setup_path( POST =>
        '/articles/'        => \&add_new_article,

    # -- when beginning to handle new CGI/FastCGI request
    my $r = CGI::Easy::Request->new();
    my $handler = path2view($r);
    # $handler now set to:
    #   \&list_articles   if url path /articles/ and request method is GET
    #   \&add_new_article if url path /articles/ and request method is POST
    #   \&list_articles   if url path /articles.php (any request method)
    #   \&show_home_page  if url path /index.php (any request method)
    #   undef             (in all other cases)

    # -- while CGI/FastCGI initialization
        \&list_articles     => '/articles/',
        # we don't have to configure mapping for \&show_home_page
        # and \&add_new_article because their mappings can be
        # unambiguously automatically detected from above setup_path()

    # -- when preparing reply (HTML escaping omitted for simplicity)
    printf '<a href="%s">Articles</a>', view2path(\&list_articles);
    printf '<form method=POST action="%s">', view2path(\&add_new_article);
    # -- or redirecting to another url
    my $h = CGI::Easy::Headers->new();

These two parts (setup_path() with path2view() and setup_view() with view2path()) can be used independently - for example, you don't have to use setup_view() and view2path() if you prefer to hardcode urls in HTML templates instead of generating them dynamically. But using both parts will let you configure all urls used in your application in single place, which make it easier to control and modify them.

In addition to simple constant path to handler and vice versa mapping you can also map any path matching regular expression and even copy some data from path to GET parameters. Example:

    # make /article/123/ same as /index.php?id=123
    # use same handler for any url beginning with /old/
        '/article.php'          => \&show_article,
        qr{^/article/(\d+)/$}   => set_param('id') => \&show_article,
        qr{^/old/}              => \&unsupported,

    # generate urls like /article/123/ dynamically
        \&show_article          => [
            with_params('id')       => '/article/?/',
    $url = view2path(\&show_article, id=>123);


setup_path( [METHOD =>] MATCH => [CALLBACK => ...] HANDLER, ... )

Configure mapping of url's path to handler subroutine (which will be used by path2view()). Can be called multiple times and will just add new mapping rules on each call.

If optional METHOD parameter defined, then all mapping rules in this setup_path() call will be applied only for requests with that HTTP method. If METHOD doesn't used, then these rules will be applied to all HTTP methods. If some path match both rules defined for current HTTP method and rules defined for any HTTP methods, will be used rule defined for current HTTP method.

MATCH parameter should be either SCALAR (string equal to url path) or Regexp (which can match any part of url path).

HANDLER is REF to your subroutine, which will be returned by path2view() when this rule will match current url.

Between MATCH and HANDLER any amount of optional CALLBACK subroutines can be used. These CALLBACKs will be called when MATCH rule matches current url with two parameters: CGI::Easy::Request object and ARRAYREF with contents of all capturing parentheses (when MATCH rule is Regexp with capturing parentheses). Usual task for such CALLBACKs is convert "hidden" CGI parameters included in url path into usual $r->{GET} parameters.

Return nothing.

path2view( $r )

Take CGI::Easy::Request object as parameter, and analyse this request according to rules defined previously using setup_path().

Return: HANDLER if find rule which match current request, else undef().

set_param( @names )

Take names of {GET} parameters which should be set using parts of url path selected by capturing parentheses in MATCH Regexp.

Return CALLBACK subroutine suitable for using in setup_path().

setup_view( HANDLER => PATH, ... )

Configure mapping of handler subroutine to url path (which will be used by view2path()). Can be called multiple times and will just add new mapping rules on each call.

HANDLER must be REF to user's subroutine used to handle requests on PATH.

PATH can be either STRING or ARRAYREF.

If PATH is ARRAYREF, then this array should consist of CALLBACK => TEMPLATE pairs. CALLBACK is subroutine which will be executed by view2path() with single parameter \%params, and should return either FALSE if this CALLBACK unable to handle these %params, or ARRAYREF with values to substitute into path TEMPLATE. TEMPLATE is path STRING which may contain '?' symbols - these will be replaced by values returned in ARRAYREF by CALLBACK which successfully handle %params.

Example: map \&handler to /first/ or /second/ with 50% probability

        \&handler   => [
            sub { return rand < 0.5 ? [] : undef }  => '/first/',
            sub { return []                      }  => '/second/',

Example: map \&handler to random article with id 0-999

        \&handler   => [
            sub { return [ int rand 1000 ] }    => '/article/?/',

Return nothing.

view2path( HANDLER, %params )

Take user handler subroutine and it parameters, and convert it to url according to rules defined previously using setup_view().


        \&handler   => 'index.php',
    my $url = view2path(\&handler, a=>'some string', b=>[6,7]);
    # $url will be: 'index.php?a=some%20string&b=6&b=7'

If simple mapping from STRING to HANDLER was defined using setup_path(), and this is only mapping to HANDLER defined, then it's not necessary to define reverse mapping using setup_view() - it will be defined automatically.


        '/articles/'    => \&list_articles,
    my $url = view2path(\&list_articles);
    # $url will be: '/articles/'

Return: url. Throw exception if unable to make url.

with_params( @names )

Take names of parameters which must exists in %params given to view2path().

Return CALLBACK subroutine suitable for using in setup_view().


Bugs / Feature Requests

Please report any bugs or feature requests through the issue tracker at You will be notified automatically of any progress on your issue.

Source Code

This is open source software. The code repository is available for public review and contribution under the terms of the license. Feel free to fork the repository and submit pull requests.

    git clone



Alex Efros <>


This software is Copyright (c) 2009-2010 by Alex Efros <>.

This is free software, licensed under:

  The MIT (X11) License
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