[[!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.
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.
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
:
<TMPL_IF NAME="OTHERLANGUAGES">
<div id="otherlanguages">
<ul>
<TMPL_LOOP NAME="OTHERLANGUAGES">
<li>
<a href="<TMPL_VAR NAME="URL">"><TMPL_VAR NAME="LANGUAGE"></a>
<TMPL_UNLESS NAME="MASTER">
(<TMPL_VAR NAME="PERCENT"> %)
</TMPL_UNLESS>
</li>
</TMPL_LOOP>
</ul>
</div>
</TMPL_IF>
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:
<TMPL_IF NAME="ISTRANSLATION">
<div id="percenttranslated">
<TMPL_VAR NAME="PERCENTTRANSLATED">
</div>
</TMPL_IF>
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:
- updates the POT file and the PO files for the "slave" languages;
the updated PO files are then put under version control;
- 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
Once the fix to
[[bugs/pagetitle_function_does_not_respect_meta_titles]] from
[[intrigeri]]'s meta
branch is merged into ikiwiki upstream, the
generated links' text will be optionally based on the page titles set
with the [[meta|plugins/meta]] plugin, and will thus be translatable.
It will also allow displaying the translation status in links to slave
pages. Both were implemented, and reverted in commit
ea753782b222bf4ba2fb4683b6363afdd9055b64, which should be reverted
once [[intrigeri]]'s meta
branch is merged.
An integration branch, called meta-po
, merges [[intrigeri]]'s po
and meta
branches, and thus has thise additional features.
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.