[[!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`). As detailed bellow in the security section, `po4a` is subject to denial-of-service attacks before version 0.35. [[!toc levels=2]] Introduction ============ A language is chosen as the "master" one, and any other supported language is a "slave" one. A page written in the "master" language is a "master" page. It can be of any page type supported by ikiwiki, except `po`. It does not have to be named a special way: migration to this plugin does not imply any page renaming work. Example: `bla/page.mdwn` is a "master" Markdown page written in English; if `usedirs` is enabled, it is rendered as `bla/page/index.en.html`, else as `bla/page.en.html`. Any translation of a "master" page into a "slave" language is called a "slave" page; it is written in the gettext PO format. `po` is now a page type supported by ikiwiki. 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.fr.html`, else as `bla/page.fr.html` (In)Compatibility ================= This plugin does not support the `indexpages` mode. If you don't know what it is, you probably don't care. Configuration ============= Supported languages ------------------- `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' => 'Français', 'es' => 'Castellano', 'de' => 'Deutsch', } Decide which pages are translatable ----------------------------------- The `po_translatable_pages` setting configures what pages are translatable. It is a [[ikiwiki/PageSpec]], so you have lots of control over what kind of pages are translatable. The `.po` files are not considered as being translatable, so you don't need to worry about excluding them explicitly from this [[ikiwiki/PageSpec]]. Internal links -------------- ### Links targets The `po_link_to` option in `ikiwiki.setup` is used to decide how internal links should be generated, depending on web server features and site-specific preferences. #### Default linking behavior If `po_link_to` is unset, or set to `default`, ikiwiki's default linking behavior is preserved: `\[[destpage]]` links to the master language's page. #### Link to current language If `po_link_to` is set to `current`, `\[[destpage]]` links to the `destpage`'s version written in the current page's language, if available, *i.e.*: * `foo/destpage/index.LL.html` if `usedirs` is enabled * `foo/destpage.LL.html` if `usedirs` is disabled #### Link to negotiated language If `po_link_to` is set to `negotiated`, `\[[page]]` links to the negotiated preferred language, *i.e.* `foo/page/`. (In)compatibility notes: * if `usedirs` is disabled, it does not make sense to set `po_link_to` to `negotiated`; this option combination is neither implemented nor allowed. * if the web server does not support Content Negotiation, setting `po_link_to` to `negotiated` will produce a unusable website. ### Links appearance When `po_translation_status_in_links` is enabled, the text of a link to a slave pages displays this page's translation status. When the `po_strictly_refresh_backlinks` setting is enabled, a page is refreshed every time a backlinked page is changed. This updates the translation status in links, and helps having a consistent translated wiki. Beware, this make every page depend on every page that links to it, which can slow everything down and bloat the dependency pagespecs. Server support ============== Apache ------ Using Apache `mod_negotiation` makes it really easy to have Apache serve any 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` (replace `LL` with your default MIME language code) for the wiki context can help to ensure `bla/page/index.en.html` is served as `Content-Language: LL`. lighttpd -------- lighttpd unfortunately does not support content negotiation. **FIXME**: does `mod_magnet` provide the functionality needed to emulate this? Usage ===== Templates --------- When `po_link_to` is not set to `negotiated`, one should replace some occurrences of `BASEURL` with `HOMEPAGEURL` to get correct links to the wiki homepage. The `ISTRANSLATION` and `ISTRANSLATABLE` variables can be used to display things only on translatable or translation pages. ### Display page's versions in other languages The `OTHERLANGUAGES` loop provides ways to display other languages' versions of the same page, and the translations' status. One typically adds the following code to `templates/page.tmpl`:
The following variables are available inside the loop (for every page in): * `URL` - url to the page * `CODE` - two-letters language code * `LANGUAGE` - language name (as defined in `po_slave_languages`) * `MASTER` - is true (1) if, and only if the page is a "master" page * `PERCENT` - for "slave" pages, is set to the translation completeness, in percents ### Display the current translation status The `PERCENTTRANSLATED` variable is set to the translation completeness, expressed in percent, on "slave" pages. One can use it this way:
Additional PageSpec tests ------------------------- This plugin enhances the regular [[ikiwiki/PageSpec]] syntax with some additional tests that are documented [[here|ikiwiki/pagespec/po]]. Automatic PO file update ------------------------ Committing changes to a "master" page: 1. updates the POT file and the PO files for the "slave" languages; the updated PO files are then put under version control; 2. triggers a refresh of the corresponding HTML slave pages. Also, when the plugin has just been enabled, or when a page has just been declared as being translatable, the needed POT and PO files are created, and the PO files are checked into version control. Discussion pages and other sub-pages ------------------------------------ Discussion should happen in the language in which the pages are written for real, *i.e.* the "master" one. If discussion pages are enabled, "slave" pages therefore link to the "master" page's discussion page. Likewise, "slave" pages are not supposed to have sub-pages; [[WikiLinks|wikilink]] that appear on a "slave" page therefore link to the master page's sub-pages. Translating ----------- One can edit the PO files using ikiwiki's CGI (a message-by-message interface could also be implemented at some point). If [[tips/untrusted_git_push]] is setup, one can edit the PO files in one's preferred `$EDITOR`, without needing to be online. Markup languages support ------------------------ Markdown is well supported. Some other markup languages supported by ikiwiki mostly work, but some pieces of syntax are not rendered correctly on the slave pages: * [[reStructuredText|rst]]: anonymous hyperlinks and internal cross-references * [[wikitext]]: conversion of newlines to paragraphs * [[creole]]: verbatim text is wrapped, tables are broken * [[html]] and LaTeX: not supported yet; the dedicated po4a modules could be used to support them, but they would need a security audit * other markup languages have not been tested. Security ======== [[./security]] contains a detailed security analysis of this plugin and its dependencies. When using po4a older than 0.35, it is recommended to uninstall `Text::WrapI18N` (Debian package `libtext-wrapi18n-perl`), in order to avoid a potential denial of service. TODO ==== Better links ------------ ### Page title in links Using the fix to [[bugs/pagetitle_function_does_not_respect_meta_titles]] from [[intrigeri]]'s `meta` branch, the generated links' text is based on the page titles set with the [[meta|plugins/meta]] plugin. This has to be merged into ikiwiki upstream, though. Robustness tests ---------------- ### Enabling/disabling the plugin * enabling the plugin with `po_translatable_pages` set to blacklist: **OK** * enabling the plugin with `po_translatable_pages` set to whitelist: **OK** * enabling the plugin without `po_translatable_pages` set: **OK** * disabling the plugin: **OK** ### Changing the plugin config * adding existing pages to `po_translatable_pages`: **OK** * removing existing pages from `po_translatable_pages`: **OK** * adding a language to `po_slave_languages`: **OK** * removing a language from `po_slave_languages`: **OK** * changing `po_master_language`: **OK** * replacing `po_master_language` with a language previously part of `po_slave_languages`: needs two rebuilds, but **OK** (this is quite a perverse test actually) ### Creating/deleting/renaming pages All cases of master/slave page creation/deletion/rename, both via RCS and via CGI, have been tested. ### Misc * general test with `usedirs` disabled: **OK** * general test with `indexpages` enabled: **not OK** * general test with `po_link_to=default` with `userdirs` enabled: **OK** * general test with `po_link_to=default` with `userdirs` disabled: **OK** Misc. bugs ---------- Documentation ------------- Maybe write separate documentation depending on the people it targets: translators, wiki administrators, hackers. This plugin may be complex enough to deserve this.