NAME
    Catalyst::Plugin::I18N::PathPrefix - Language prefix in the request path

VERSION
    Version 0.01

SYNOPSIS
      # in MyApp.pm
      use Catalyst qw/
        I18N I18N::PathPrefix
      /;
      __PACKAGE__->config('Plugin::I18N::PathPrefix' => {
        valid_languages => [qw/en de fr/],
        fallback_language => 'en',
        language_independent_paths => qr{
            ^( votes/ | captcha/numeric/ )
        }x,
      });
      __PACKAGE__->setup;

      # now the language is selected based on requests paths:
      #
      # http://www.example.com/en/foo/bar -> sets $c->language to 'en',
      #                                      dispatcher sees /foo/bar
      #
      # http://www.example.com/de/foo/bar -> sets $c->language to 'de',
      #                                      dispatcher sees /foo/bar
      #
      # http://www.example.com/fr/foo/bar -> sets $c->language to 'fr',
      #                                      dispatcher sees /foo/bar
      #
      # http://www.example.com/foo/bar    -> sets $c->language from
      #                                      Accept-Language header,
      #                                      dispatcher sees /foo/bar

      # in a controller
      sub language_switch : Private
      {
        # the template will display the language switch
        $c->stash('language_switch' => $c->language_switch_options);
      }

DISCLAIMER
    This is ALPHA SOFTWARE. Use at your own risk. Features may change.

DESCRIPTION
    This module allows you to put the language selector as a prefix to the
    path part of the request URI without requiring any modifications to the
    controllers (like restructuring all the controllers to chain from a
    common base controller).

    (Internally it strips the language code from "$c->req->path" and appends
    it to "$c->req->base" so that the invariant "$c->req->uri eq
    $c->req->base . $c->req->path" still remains valid, but the dispatcher
    does not see the language code - it uses "$c->req->path" only.)

    Throughout this document 'language code' means ISO 639-1 2-letter
    language codes, case insensitively (eg. 'en', 'de', 'it', 'EN'), just
    like I18N::LangTags supports them.

    Note: You have to load Catalyst::Plugin::I18N if you load this plugin.

    Note: HTTP already have a standard way (ie. Accept-Language header) to
    allow the user specify the language (s)he prefers the page to be
    delivered in. Unfortunately users often don't set it properly, but more
    importantly Googlebot does not really support it (but requires that you
    always serve documents of the same language on the same URI). So if you
    want a SEO-optimized multi-lingual site, you have to have different
    (sub)domains for the different languages, or resort to putting the
    language selector into the URL.

CONFIGURATION
    You can use these configuration options under the
    'Plugin::I18N::PathPrefix' key:

  valid_languages
      valid_languages => \@language_codes

    The language codes that are accepted as path prefix.

  fallback_language
      fallback_language => $language_code

    The fallback language code used if the URL contains no language prefix
    and Catalyst::Plugin::I18N cannot auto-detect the preferred language
    from the "Accept-Language" header or none of the detected languages are
    found in "valid_languages".

  language_independent_paths
      language_independent_paths => $regex

    If the URI path is matched by $regex, do not add language prefix and
    ignore if there's one (and pretend as if the URI did not contain any
    language prefix, ie. rewrite "$c->req->uri", "$c->req->base" and
    "$c->req->path" to remove the prefix from them).

    Use a regex that matches all your paths that return language independent
    information.

  debug
      debug => $boolean

    If set to a true value, "prepare_path_prefix" logs its actions (using
    "$c->log->debug(...)").

METHODS
  setup_finalize
    Overridden (wrapped with an an "after" modifier) from "setup_finalize"
    in Catalyst.

    Sets up the package configuration.

  prepare_path
    Overridden (wrapped with an an "after" modifier) from "prepare_path" in
    Catalyst.

    Calls "$c->prepare_path_prefix" after the original method.

  prepare_path_prefix
      $c->prepare_path_prefix()

    Returns: N/A

    If "$c->req->path" is matched by the "language_independent_paths"
    configuration option then calls "$c->set_languages_from_language_prefix"
    with the value of the "fallback_language" configuration option and
    returns.

    Otherwise, if "$c->req->path" starts with a language code listed in the
    "valid_languages" configuration option, then splits language prefix from
    "$c->req->path" then appends it to "$c->req->base" and calls
    "$c->set_languages_from_language_prefix" with this language prefix.

    Otherwise, it tries to select an appropriate language code:

    *   It picks the first language code "$c->languages" that is also
        present in the "valid_languages" configuration option.

    *   If no such language code, uses the value of the "fallback_language"
        configuration option.

    Then appends this language code to "$c->req->base" and the path part of
    "$c->req->uri", finally calls "$c->set_languages_from_language_prefix"
    with that language code.

  set_languages_from_language_prefix
      $c->set_languages_from_language_prefix($language_code)

    Returns: N/A

    Sets "$c->languages" to $language_code.

    Called from both "prepare_path_prefix" and "switch_language" (ie. always
    called when "$c->languages" is set by this module).

    You can wrap this method (using eg. the "after" in Moose method
    modifier) so you can store the language code into the stash if you like:

      after prepare_path_prefix => sub {
        my $c = shift;

        $c->stash('language' => $c->language);
      };

  uri_for_in_language
      $c->uri_for_in_language($language_code => @uri_for_args)

    Returns: $uri_object

    The same as "uri_for" in Catalyst but returns the URI with the
    $language_code path prefix (independently of what the current language
    is).

    Internally this method temporarily sets the paths in "$c->req", calls
    "uri_for" in Catalyst then resets the paths. Ineffective, but you
    usually call it very infrequently.

    Note: You should not call this method to generate language-independent
    paths, as it will generate invalid URLs currently (ie. the language
    independent path prefixed with the language prefix).

    Note: This module intentionally does not override "uri_for" in Catalyst
    but provides this method instead: "uri_for" in Catalyst is usually
    called many times per request, and most of the cases you want it to use
    the current language; not overriding it can be a significant performance
    saving. YMMV.

  switch_language
      $c->switch_language($language_code)

    Returns: N/A

    Changes "$c->req->base" to end with $language_code and calls
    "$c->set_languages_from_language_prefix" with $language_code.

    Useful if you want to switch the language later in the request
    processing (eg. from a request parameter, from the session or from the
    user object).

  language_switch_options
      $c->language_switch_options()

    Returns: "{ $language_code => { name => $language_name, uri => $uri },
    ... }"

    Returns a data structure that contains all the necessary data (language
    code, name, URL of the same page) for displaying a language switch
    widget on the page.

    The data structure is a hashref with one key for each valid language
    code (see the "valid_languages" config option) (in all-lowercase format)
    and the value is a hashref that contains the following key-value pairs:

    name
        The localized (translated) name of the language. (The actual msgid
        used in "$c->loc()" is the English name of the language, returned by
        "name" in I18N::LangTags::List.)

    url The URL of the equivalent of the current page in that language (ie.
        the language prefix replaced).

    You can find an example TT2 HTML template for the language switch
    included in the distribution.

SEE ALSO
    Catalyst::Plugin::I18N, Catalyst::TraitFor::Request::PerLanguageDomains

AUTHOR
    Norbert Buchmuller, "<norbi at nix.hu>"

TODO
    make "uri_for_in_language" work on language-independent URIs
    support locales instead of language codes

BUGS
    Please report any bugs or feature requests to
    "bug-catalyst-plugin-i18n-pathprefix at rt.cpan.org", or through the web
    interface at
    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Catalyst-Plugin-I18N-Pat
    hPrefix>. I will be notified, and then you'll automatically be notified
    of progress on your bug as I make changes.

SUPPORT
    You can find documentation for this module with the perldoc command.

        perldoc Catalyst::Plugin::I18N::PathPrefix

    You can also look for information at:

    *   RT: CPAN's request tracker

        <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Catalyst-Plugin-I18N-PathP
        refix>

    *   AnnoCPAN: Annotated CPAN documentation

        <http://annocpan.org/dist/Catalyst-Plugin-I18N-PathPrefix>

    *   CPAN Ratings

        <http://cpanratings.perl.org/d/Catalyst-Plugin-I18N-PathPrefix>

    *   Search CPAN

        <http://search.cpan.org/dist/Catalyst-Plugin-I18N-PathPrefix/>

ACKNOWLEDGEMENTS
    Thanks for Larry Leszczynski for the idea of appending the language
    prefix to "$c->req->base" after it's split off of "$c->req->path"
    (<http://dev.catalystframework.org/wiki/wikicookbook/urlpathprefixing>).

    Thanks for Tomas (t0m) Doran <bobtfish@bobtfish.net> for the code
    reviews, improvement ideas and mentoring in general.

COPYRIGHT & LICENSE
    Copyright 2010 Norbert Buchmuller, all rights reserved.

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

