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[[!template id=plugin name=po core=0 author="[[intrigeri]]"]] [[!tag type/format]]

This plugin adds support for multi-lingual wikis, translated with gettext, using [po4a|http://po4a.alioth.debian.org/].

It depends on the Perl Locale::Po4a::Po library (apt-get install po4a).

Introduction

A language is decided to be the "master" one, and any other supported language is a "slave" one. A page written in the "master" language is a "master" page, and is written in any supported format but PO.

Example: bla/page.mdwn is a "master" Markdown page written in English; if usedirs is enabled, it is rendered as bla/page/index.html, else as bla/page.html.

Translations of a "master" page into a "slave" language are called "slave" pages, and is a in gettext PO format. PO is thus promoted to the wiki page type status.

Example: bla/page.fr.po is the PO "message catalog" used to translate bla/page.mdwn into French; if usedirs is enabled, it is rendered as bla/page/index.html.fr, else as bla/page.html.fr

Configuration

po_master_language is used to set the master language in ikiwiki.setup, such as:

    po_master_language => { 'code' => 'en', 'name' => 'English' }

po_slave_languages is used to set the list of supported "slave" languages, such as:

    po_slave_languages => { 'fr' => { 'name' => 'Français', },
                            'es' => { 'name' => 'Castellano', },
                            'de' => { 'name' => 'Deutsch', },
    },

Server support

Apache

Using mod_negotiation makes it really easy to have Apache serve the page in the client's preferred language, if available. This is the default Debian Apache configuration.

When usedirs is enabled, one has to set DirectoryIndex index for the wiki context.

Setting DefaultLanguage LL for the wiki context can be needed, to ensure bla/page/index.html is served as Content-Language: LL (replace LL with your default MIME language).

lighttpd

lighttpd unfortunately does not support content negotiation.

TODO

Display available translations

The [[linguas|plugins/contrib/linguas]] plugin has some code that can be used as a basis to display the existing translations, and allow to navigate between them.

View translation status

One should be able to view some freshness information about the translation status, either for a given page or for the whole wiki.

This should not be too hard using gettext tools. If this is implemented as a [[HTML::Template|http://search.cpan.org/search?mode=dist&query=HTML%3A%3ATemplate]] loop, a page using it should depend on any "master" and "slave" pages whose status is being displayed.

Decide which pages are translatable

The subset of ("master") pages supporting translation must be configurable:

  • a [[!translatable ]] directive, when put on a page, makes it translatable
  • this [[ikiwiki/directive]] can be used with an optional match=PageSpec argument, to render translatable a bunch of pages at once

Automatic PO files update

Committing changes to a "master" page must:

  1. update the POT file, the PO files for the supported languages, and put them under version control
  2. trigger a refresh of the corresponding HTML slave pages

The former can be implemented as a needsbuild hook, which is the first type of hook to run after the list of files that need to be built is known: that is, at a time when we know which "master" page was modified, and thus, which POT/PO files have to be updated.

The latter can be implemented by making any "slave" page depend on the corresponding "master" page. The add_depends function can achieved this, if used in a FIXME hook.

UI consistency: rename "Edit" button on slave pages

It may be surprising to some, after having pressed Edit on a wiki page, to end up editing a strange PO file. The Edit button must then be be renamed to Improve translation on "slave" pages.

Translation quality assurance

Modifying a PO file via the CGI must only be allowed if the new version is a valid PO file. As a bonus, check that it provides a more complete translation than the existing one.

A new cansave type of hook would be needed to implement this.

Note: committing to the underlying repository is a way to bypass this check.

Translating online

As PO is a wiki page type, we already have an online PO editor, that is ikiwiki's CGI.

A message-by-message interface could be implemented later, providing a nice way to translate offline (without VCS access) is provided.

Translating offline without VCS access

The following workflow should be made possible for translators without VCS access who need to edit the PO files in another editor than a web browser:

  • download the PO file for the page
  • use any PO editor to update the translation
  • upload the updated PO file

A generic mechanism to download and upload a page's source is needed. It's only an alternative way to do Edit/edit/Save.

Short-term workflow

  • pretend to edit the PO file online
  • copy the PO file content from the textarea
  • cancel the edit
  • paste the content into a local file.