[[!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
).
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, and is
written in any supported format but PO. It does not have to be named
a special way: migration from/to this plugin does not imply heavy
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
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', }
}
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 *.LL.po
translations files are anyway not considered as being
translatable, so you don't need to worry about excluding them manually
from this [[ikiwiki/PageSpec]].
Internal links
One can use the po_link_to_
option in ikiwiki.setup
to choose 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: [[page]]
links to the master
language's page.
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:
po_link_to => negotiated
provides no useful behavior if usedirs
is disabled; this option combination is neither implemented nor
allowed
po_link_to => negotiated
provides no useful behavior if the web
server does not support Content Negotiation
Link to current language
If po_link_to
is set to current
and the destination page is either
a translatable page or a translation, [[page]]
links to the current
page's language, i.e.:
foo/page/index.LL.html
if usedirs
is enabled
foo/page.LL.html
if usedirs
is disabled
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
(replace LL
with your default MIME
language) for the wiki context can be needed, to ensure
bla/page/index.en.html
is served as Content-Language: LL
.
FIXME: is it still needed with the new .en.html
naming convention?
lighttpd
lighttpd unfortunately does not support content negotiation.
FIXME: does mod_magnet
provide the functionality needed to
emulate this?
TODO
Optimization
Pre-compute what can be early in the build process:
- the list of translatable (master) pages
- for every translatable page, the list of slave pages
... and/or memoize istranslation
/istranslatable
function calls.
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 information about the translation
completeness, 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.
Automatic PO files update
Committing changes to a "master" page must:
- update the POT file and the PO files for the supported languages,
before putting them under version control
- trigger a refresh of the corresponding HTML slave pages
The former is to be done at a time when:
- we know which "master" page was modified, and thus, which POT/PO
files have to be updated: the
needsbuild
hook is the first one to
run that provides us with the necessary information
- we can modify the list of pages needing a refresh; this is
needsbuild
hook's job
The latter can be implemented by making any "slave" page depend on the
corresponding "master" page. The add_depends
function can achieve
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 looking PO file. The Edit button
displayed on "slave" pages must therefore be renamed Improve
translation .
Pages selection depending on language
To improve user navigation in a multi-lingual wiki, site developers
must be enabled to write:
\[[!map pages="dev/* and lang(LL)" feeds="no"]]
\[[!map pages="dev/* and currentlang()" feeds="no"]]
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 also be implemented at some
point; a nice way to do offline translation work (without VCS access)
still has to be offered, though.
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 page's PO file
- use any PO editor to update the translation
- upload the updated PO file
Implementation note: a generic mechanism to upload a page's source is
needed: it's only an alternative way to allow saving a the modified
page's source with the CGI.
Short-term workflow
A possible workaround is:
- 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.
- edit the local file in any PO editor
- pretend to edit the PO file online
- paste the modified local file's content into the edit textarea
- save