X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/ae827a43f84bf18f971ff891d1d4f8d0c19b043c..86edd539f4995b49e57086e055b0c9a5571b2ff3:/doc/plugins/po.mdwn diff --git a/doc/plugins/po.mdwn b/doc/plugins/po.mdwn index b702414c0..6c0d49197 100644 --- a/doc/plugins/po.mdwn +++ b/doc/plugins/po.mdwn @@ -6,15 +6,17 @@ gettext, using [po4a](http://po4a.alioth.debian.org/). It depends on the Perl `Locale::Po4a::Po` library (`apt-get install po4a`). +[[!toc]] + 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 +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 @@ -22,7 +24,7 @@ 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 "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 @@ -33,7 +35,10 @@ 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 +Supported languages +------------------- + +`po_master_language` is used to set the "master" language in `ikiwiki.setup`, such as: po_master_language => { 'code' => 'en', 'name' => 'English' } @@ -41,9 +46,9 @@ Configuration `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', } + po_slave_languages => { 'fr' => 'Français', + 'es' => 'Castellano', + 'de' => 'Deutsch', } Decide which pages are translatable @@ -53,44 +58,43 @@ 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]]. +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 -------------- -One can use the `po_link_to_` option in `ikiwiki.setup` to choose how +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: `[[page]]` links to the master +linking behavior is preserved: `\[[destpage]]` links to the master language's page. -### Link to negotiated language +### Link to current language -If `po_link_to` is set to `negotiated`, `[[page]]` links to the -negotiated preferred language, *i.e.* `foo/page/`. +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.*: -(In)compatibility notes: +- `foo/destpage/index.LL.html` if `usedirs` is enabled +- `foo/destpage.LL.html` if `usedirs` is disabled -- `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 negotiated language -### Link to current language +If `po_link_to` is set to `negotiated`, `\[[page]]` links to the +negotiated preferred language, *i.e.* `foo/page/`. -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.*: +(In)compatibility notes: -- `foo/page/index.LL.html` if `usedirs` is enabled -- `foo/page.LL.html` if `usedirs` is disabled +- 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 @@ -99,17 +103,16 @@ 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. +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) for the wiki context can be needed, to ensure +language code) for the wiki context can help 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 -------- @@ -120,113 +123,200 @@ lighttpd unfortunately does not support content negotiation. emulate this? -TODO -==== +Usage +===== -Display available translations ------------------------------- +Templates +--------- -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. +The `ISTRANSLATION` and `ISTRANSLATABLE` variables can be used to +display things only on translatable or translation pages. -View translation status ------------------------ +### Display page's versions in other languages -One should be able to view some information about the translation -completeness, either for a given page or for the whole wiki. +The `OTHERLANGUAGES` loop provides ways to display other languages' +versions of the same page, and the translations' status. -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. +One typically adds the following code to `templates/page.tmpl`: -Automatic PO files update -------------------------- + +
+ +
+ -Committing changes to a "master" page must: +The following variables are available inside the loop (for every page in): -1. update the POT file and the PO files for the supported languages, - before putting them under version control -2. trigger a refresh of the corresponding HTML slave pages +- `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 -The former is to be done at a time when: +### Display the current translation status -- 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 `PERCENTTRANSLATED` variable is set to the translation +completeness, expressed in percent, on "slave" pages. -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. +One can use it this way: -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* . +Additional PageSpec tests +------------------------- -Pages selection depending on language -------------------------------------- +This plugin enhances the regular [[ikiwiki/PageSpec]] syntax with some +additional tests that are documented [[here|ikiwiki/pagespec/po]]. -To improve user navigation in a multi-lingual wiki, site developers -must be enabled to write: +Automatic PO file update +------------------------ - \[[!map pages="dev/* and lang(LL)" feeds="no"]] +Committing changes to a "master" page: - \[[!map pages="dev/* and currentlang()" feeds="no"]] +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. -Translation quality assurance ------------------------------ +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. -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. +Discussion pages +---------------- -A new `cansave` type of hook would be needed to implement this. +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. -Note: committing to the underlying repository is a way to bypass -this check. +Translating +----------- -Translating online ------------------- +One can edit the PO files using ikiwiki's CGI (a message-by-message +interface could also be implemented at some point). -As PO is a wiki page type, we already have an online PO editor, that -is ikiwiki's CGI. +If [[tips/untrusted_git_push]] is setup, one can edit the PO files in one's +preferred `$EDITOR`, without needing to be online. -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. +TODO +==== -Translating offline without VCS access --------------------------------------- +Security checks +--------------- + +### Security history + +The only past security issues I could find in GNU gettext and po4a +are: + +- [CVE-2004-0966](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0966), + *i.e.* [Debian bug #278283](http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=278283): + the autopoint and gettextize scripts in the GNU gettext package + 1.14 and later versions, as used in Trustix Secure Linux 1.5 + through 2.1 and other operating systems, allows local users to + overwrite files via a symlink attack on temporary files. +- [CVE-2007-4462](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-4462): + `lib/Locale/Po4a/Po.pm` in po4a before 0.32 allows local users to + overwrite arbitrary files via a symlink attack on the + gettextization.failed.po temporary file. + +**FIXME**: check whether this plugin would have been a possible attack +vector to exploit these vulnerabilities. + +Depending on my mood, the lack of found security issues can either +indicate that there are none, or reveal that no-one ever bothered to +find (and publish) them. + +### PO file features + +Can any sort of directives be put in po files that will cause mischief +(ie, include other files, run commands, crash gettext, whatever)? + +> No [documented](http://www.gnu.org/software/gettext/manual/gettext.html#PO-Files) +> directive is supposed to do so. + +### Running po4a on untrusted content + +Are there any security issues on running po4a on untrusted content? + +> To say the least, this issue is not well covered, at least publicly: +> +> - the documentation does not talk about it; +> - grep'ing the source code for `security` or `trust` gives no answer. +> +> I'll ask their opinion to the po4a maintainers. +> +> I'm not in a position to audit the code, but I had a look anyway: +> +> - no use of `system()`, `exec()` or backticks in `Locale::Po4a`; are +> there any other way to run external programs in Perl? +> - a symlink attack vulnerability was already discovered, so I "hope" +> the code has been checked to find some more already +> - the po4a parts we are using themselves use the following Perl +> modules: `DynaLoader`, `Encode`, `Encode::Guess`, +> `Text::WrapI18N`, `Locale::gettext` (`bindtextdomain`, +> `textdomain`, `gettext`, `dgettext`) +> +> --[[intrigeri]] + +### Fuzzing input + +I was not able to find any public information about gettext or po4a +having been tested with a fuzzing program, such as `zzuf` or `fusil`. +Moreover, some gettext parsers seem to be quite +[easy to crash](http://fusil.hachoir.org/trac/browser/trunk/fuzzers/fusil-gettext), +so it might be useful to bang gettext/po4a's heads against such +a program in order to easily detect some of the most obvious DoS. +[[--intrigeri]] + +gettext/po4a rough corners +-------------------------- + +- fix infinite loop when synchronizing two ikiwiki (when checkouts + live in different directories): say bla.fr.po has been updated in + repo2; pulling repo2 from repo1 seems to trigger a PO update, that + changes bla.fr.po in repo1; then pushing repo1 to repo2 triggers + a PO update, that changes bla.fr.po in repo2; etc.; quickly fixed in + `629968fc89bced6727981c0a1138072631751fee`, by disabling references + in Pot files. Using `Locale::Po4a::write_if_needed` might be + a cleaner solution. +- new translations created in the web interface must get proper + charset/encoding gettext metadata, else the next automatic PO update + removes any non-ascii chars; possible solution: put such metadata + into the Pot file, and let it propagate; should be fixed in + `773de05a7a1ee68d2bed173367cf5e716884945a`, time will tell. + +Misc. improvements +------------------ -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: +### page titles -- download the page's PO file -- use any PO editor to update the translation -- upload the updated PO file +Use nice page titles from meta plugin in links, as inline already +does. This is actually a duplicate for +[[bugs/pagetitle_function_does_not_respect_meta_titles]], which might +be fixed by something like [[todo/using_meta_titles_for_parentlinks]]. -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. +Translation quality assurance +----------------------------- -### Short-term workflow +Modifying a PO file via the CGI must be forbidden if the new version +is not a valid PO file. As a bonus, check that it provides a more +complete translation than the existing one. -A possible workaround is: +A new `cansave` type of hook would be needed to implement this. -- 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 +Note: committing to the underlying repository is a way to bypass +this check.