X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/40324175aa19a9940d4e1d30d61dfef205d80dc9..a42de69fbb3e775dd407d24bf90534a07219710a:/doc/plugins/po.mdwn?ds=inline
diff --git a/doc/plugins/po.mdwn b/doc/plugins/po.mdwn
index ea1e89278..b701d3662 100644
--- a/doc/plugins/po.mdwn
+++ b/doc/plugins/po.mdwn
@@ -5,6 +5,8 @@ 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]]
@@ -31,6 +33,12 @@ 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
=============
@@ -41,15 +49,15 @@ 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_master_language => 'en|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',
- }
+ po_slave_languages => [ 'fr|Français',
+ 'es|Español',
+ 'de|Deutsch',
+ ]
Decide which pages are translatable
-----------------------------------
@@ -64,39 +72,40 @@ 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
+#### 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
+#### 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
+* `foo/destpage/index.LL.html` if `usedirs` is enabled
+* `foo/destpage.LL.html` if `usedirs` is disabled
-### Link to negotiated language
+#### 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`
+* 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
+* if the web server does not support Content Negotiation, setting
`po_link_to` to `negotiated` will produce a unusable website.
-
Server support
==============
@@ -105,23 +114,28 @@ 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.
+Add 'Options MultiViews' to the wiki directory's configuration in Apache.
+
+When `usedirs` is enabled, you should also set `DirectoryIndex index`.
+
+These settings are also recommended, in order to avoid serving up rss files
+as index pages:
-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`.
+ AddType application/rss+xml;qs=0.8 .rss
+ AddType application/atom+xml;qs=0.8 .atom
+
+For details, see [Apache's documentation](http://httpd.apache.org/docs/2.2/content-negotiation.html).
lighttpd
--------
-lighttpd unfortunately does not support content negotiation.
+Recent versions of lighttpd should be able to use
+`$HTTP["language"]` to configure the translated pages to be served.
-**FIXME**: does `mod_magnet` provide the functionality needed to
- emulate this?
+See [Lighttpd Issue](http://redmine.lighttpd.net/issues/show/1119)
+TODO: Example
Usage
=====
@@ -136,48 +150,29 @@ the wiki homepage.
The `ISTRANSLATION` and `ISTRANSLATABLE` variables can be used to
display things only on translatable or translation pages.
+The `LANG_CODE` and `LANG_NAME` variables can respectively be used to
+display the current page's language code and pretty name.
+
### 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`:
-
-
-
-
---- /usr/share/perl5/Locale/Po4a/Common.pm 2008-07-21 14:54:52.000000000 -0400 -+++ Common.pm 2008-11-11 18:27:34.000000000 -0500 -@@ -30,8 +30,16 @@ - use strict; - use warnings; - --BEGIN { -- if (eval { require Text::WrapI18N }) { -+sub import { -+ my $class=shift; -+ my $wrapi18n=1; -+ if ($_[0] eq 'nowrapi18n') { -+ shift; -+ $wrapi18n=0; -+ } -+ $class->export_to_level(1, $class, @_); -+ -+ if ($wrapi18n && eval { require Text::WrapI18N }) { - - # Don't bother determining the wrap column if we cannot wrap. - my $col=$ENV{COLUMNS}; -- -##### Term::ReadKey - -`Term::ReadKey` is not a hard dependency in our case, *i.e.* po4a -works nicely without it. But the po4a Debian package recommends -`libterm-readkey-perl`, so it will probably be installed on most -systems using the po plugin. - -If `$ENV{COLUMNS}` is not set, `Locale::Po4a::Common` uses -`Term::ReadKey::GetTerminalSize()` to get the terminal size. How safe -is this? - -Part of `Term::ReadKey` is written in C. Depending on the runtime -platform, this function use ioctl, environment, or C library function -calls, and may end up running the `resize` command (without -arguments). - -IMHO, using Term::ReadKey has too far reaching implications for us to -be able to guarantee anything wrt. security. Since it is anyway of no -use in our case, I suggest we define `ENV{COLUMNS}` before loading -`Locale::Po4a::Common`, just to be on the safe side. Joey? -[[--intrigeri]] - -> Update: adding an option to disable `Text::WrapI18N`, as Nicolas -> François suggested, would as a bonus disable `Term::ReadKey` -> as well. [[--intrigeri]] - -### msgmerge - -`refreshpofiles()` runs this external program. A po4a developer -answered he does "not expect any security issues from it". - -### 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 msgmerge/po4a's heads against such -a program in order to easily detect some of the most obvious DoS. -[[--intrigeri]] - -> po4a was not fuzzy-tested, but according to one of its developers, -> "it would be really appreciated". [[--intrigeri]] - -Test conditions: - -- a 21M file containing 100 concatenated copies of all the files in my - `/usr/share/common-licenses/`; I had no existing PO file or - translated versions at hand, which renders these tests - quite incomplete. -- po4a was the Debian 0.34-2 package; the same tests were also run - after replacing the `Text` module with the CVS one (the core was not - changed in CVS since 0.34-2 was released), without any significant - difference in the results. -- Perl 5.10.0-16 - -#### po4a-gettextize - -`po4a-gettextize` uses more or less the same po4a features as our -`refreshpot` function. - -Without specifying an input charset, zzuf'ed `po4a-gettextize` quickly -errors out, complaining it was not able to detect the input charset; -it leaves no incomplete file on disk. - -So I had to pretend the input was in UTF-8, as does the po plugin. - -Two ways of crashing were revealed by this command-line: - - zzuf -vc -s 0:100 -r 0.1:0.5 \ - po4a-gettextize -f text -o markdown -M utf-8 -L utf-8 \ - -m LICENSES >/dev/null - -They are: - - Malformed UTF-8 character (UTF-16 surrogate 0xdcc9) in substitution iterator at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - Malformed UTF-8 character (fatal) at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - -and - - Malformed UTF-8 character (UTF-16 surrogate 0xdcec) in substitution (s///) at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - Malformed UTF-8 character (fatal) at /usr/share/perl5/Locale/Po4a/Po.pm line 1443. - -Perl seems to exit cleanly, and an incomplete PO file is written on -disk. I not sure whether if this is a bug in Perl or in `Po.pm`. - -> It's fairly standard perl behavior when fed malformed utf-8. As long as it doesn't -> crash ikiwiki, it's probably acceptable. Ikiwiki can do some similar things itself when fed malformed utf-8 (doesn't crash tho) --[[Joey]] - -#### po4a-translate - -`po4a-translate` uses more or less the same po4a features as our -`filter` function. - -Without specifying an input charset, same behaviour as -`po4a-gettextize`, so let's specify UTF-8 as input charset as of now. - - zzuf -cv \ - po4a-translate -d -f text -o markdown -M utf-8 -L utf-8 \ - -k 0 -m LICENSES -p LICENSES.fr.po -l test.fr - -... prints tons of occurences of the following error, but a complete -translated document is written (obviously with some weird chars -inside): - - Use of uninitialized value in string ne at /usr/share/perl5/Locale/Po4a/TransTractor.pm line 854. - Use of uninitialized value in string ne at /usr/share/perl5/Locale/Po4a/TransTractor.pm line 840. - Use of uninitialized value in pattern match (m//) at /usr/share/perl5/Locale/Po4a/Po.pm line 1002. - -While: - - zzuf -cv -s 0:10 -r 0.001:0.3 \ - po4a-translate -d -f text -o markdown -M utf-8 -L utf-8 \ - -k 0 -m LICENSES -p LICENSES.fr.po -l test.fr - -... seems to lose the fight, at the `readpo(LICENSES.fr.po)` step, -against some kind of infinite loop, deadlock, or any similar beast. -It does not seem to eat memory, though. - -Whatever format module is used does not change anything. This is thus -probably a bug in po4a's core or in a lib it depends on. - -The sub `read`, in `TransTractor.pm`, seems to be a good debugging -starting point. - -#### msgmerge - -`msgmerge` is run in our `refreshpofiles` function. I did not manage -to crash it with `zzuf`. - -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. (warning: this function runs the external - `diff` program, have to check security) -- 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. - -Better links ------------- - -### Page title in links - -To use the page titles set with the [[meta|plugins/meta]] plugin when -rendering links would be very much nicer, than the current -"filename.LL" format. This is actually a duplicate for -[[bugs/pagetitle_function_does_not_respect_meta_titles]]. - -Going to work on this in my `meta` branch. - -### Translation status in links - -See [[contrib/po]]. - -### Backlinks - -They are not updated when the source page changes (e.g. meta title). - -### Redirect after edit - -After editing master page, when using `po_link_to=negotiated`, one is -redirected to the page in her preferred language. Would be slightly -better to be redirected, in any case, to the just saved page. - -Page formats ------------- - -Markdown is well supported, great, but what about others? - -The [[po|plugins/po]] uses `Locale::Po4a::Text` for every page format; -this can be expected to work out of the box with most other wiki-like -formats supported by ikiwiki. Some of their ad-hoc syntax might be -parsed in a strange way, but the worst problems I can imagine would be -wrapping issues; e.g. there is code in po4a dedicated to prevent -re-wrapping the underlined Markdown headers. - -While it would be easy to better support formats such as [[html]] or -LaTeX, by using for each one the dedicated po4a module, this can be -problematic from a security point of view. - -**TODO**: test the more popular formats and write proper documentation -about it. - -Translation quality assurance ------------------------------ - -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 new `cansave` type of hook would be needed to implement this. - -Note: committing to the underlying repository is a way to bypass -this check. - -Creating new pages on the web ------------------------------ - -See [[contrib/po|contrib/po]]. - -Deleting/renaming pages ------------------------ - -- When a master page is renamed or deleted, its translations (and the - pot file?) must be renamed or deleted accordingly. -- Renaming a translation should be forbidden. - -Robustness tests ----------------- - -### Disabling the plugin - -- enabling the plugin with `po_translatable_pages` set -- 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 pages +Markup languages support +------------------------ -- creating a master page via RCS: **OK** -- creating a master page via CGI: **OK** +[[Markdown|mdwn]] and [[html]] are well supported. Some other markup +languages supported by ikiwiki mostly work, but some pieces of syntax +are not rendered correctly on the slave pages: -### Deleting pages +* [[reStructuredText|rst]]: anonymous hyperlinks and internal + cross-references +* [[wikitext]]: conversion of newlines to paragraphs +* [[creole]]: verbatim text is wrapped, tables are broken +* LaTeX: not supported yet; the dedicated po4a module + could be used to support it, but it would need a security audit +* other markup languages have not been tested. -- removing a master page via RCS -- removing a translation via RCS: **OK** -- removing a master page via CGI -- removing a translation via CGI: **OK** +Security +======== -### Renaming pages +[[po/discussion]] contains a detailed security analysis of this plugin +and its dependencies. -- renaming a master page via RCS -- renaming a master page and its translations via RCS -- renaming a master page via CGI -- renaming a translation via RCS -- renaming a translation via CGI +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. -### Misc +BUGS +==== -- general test with `usedirs` disabled: **OK** -- general test with `indexpages` enabled -- general test with `po_link_to=default` +[[!inline pages="bugs/po:* and !bugs/done and !link(bugs/done) and !bugs/*/*" +feeds=no actions=no archive=yes show=0]] -Documentation -------------- +TODO +==== -Maybe write separate documentation depending on the people it targets: -translators, wiki administrators, hackers. This plugin may be complex -enough to deserve this. +[[!inline pages="todo/po:* and !todo/done and !link(todo/done) and !todo/*/*" +feeds=no actions=no archive=yes show=0]]