Optimize away most expensive file prune calls, when refreshing

[git.ikiwiki.info.git] / doc / plugins / po.mdwn

diff --git a/doc/plugins/po.mdwn b/doc/plugins/po.mdwn
index 326a6f39fcd64af9536788feea4f9973b5176a93..f3b70b5f786b5f244d8e3ba4ef6a8af0b0f8db2e 100644 (file)
--- a/doc/plugins/po.mdwn
+++ b/doc/plugins/po.mdwn
@@ -2,34 +2,51 @@
 [[!tag type/format]]
 
 This plugin adds support for multi-lingual wikis, translated with
 [[!tag type/format]]
 
 This plugin adds support for multi-lingual wikis, translated with

-gettext, using [po4a|http://po4a.alioth.debian.org/].
+gettext, using [po4a](http://po4a.alioth.debian.org/).

 
 It depends on the Perl `Locale::Po4a::Po` library (`apt-get install 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
 ============
 
 
 Introduction
 ============
 

-A language is decided to be 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.
+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
 
 Example: `bla/page.mdwn` is a "master" Markdown page written in
 English; if `usedirs` is enabled, it is rendered as

-`bla/page/index.html.en`, else as `bla/page.html.en`.
+`bla/page/index.en.html`, else as `bla/page.en.html`.

 
 

-Translations of a "master" page into a "slave" language are called
-"slave" pages, and is a in gettext PO format. PO is thus promoted to
-the wiki page type status.
+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
 
 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.html.fr`, else as `bla/page.html.fr`
+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
 =============
 
 
 
 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' }
 `ikiwiki.setup`, such as:
 
         po_master_language => { 'code' => 'en', 'name' => 'English' }


@@ -37,11 +54,57 @@ Configuration
 `po_slave_languages` is used to set the list of supported "slave"
 languages, such as:
 
 `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' => 'Español',
+                                '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
 ==============
 
 Server support
 ==============


@@ -49,121 +112,217 @@ Server support
 Apache
 ------
 
 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.
+
+Add 'Options MultiViews' to the wiki directory's configuration in Apache.

 
 When `usedirs` is enabled, one has to set `DirectoryIndex index` for
 the wiki context.
 
 Setting `DefaultLanguage LL` (replace `LL` with your default MIME
 
 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.html.en` is served as `Content-Language: LL`.
-**FIXME**: is it still needed with the new `.html.en` naming convention?
+language code) for the wiki context can help to ensure
+`bla/page/index.en.html` is served as `Content-Language: LL`.
+
+For details, see [Apache's documentation](http://httpd.apache.org/docs/2.2/content-negotiation.html).

 
 lighttpd
 --------
 
 lighttpd unfortunately does not support content negotiation.
 
 
 lighttpd
 --------
 
 lighttpd unfortunately does not support content negotiation.
 

+**FIXME**: does `mod_magnet` provide the functionality needed to
+ emulate this?

 
 

-TODO
-====

 
 

-Display available translations
-------------------------------
+Usage
+=====

 
 

-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.
+Templates
+---------

 
 

-View translation status
------------------------
+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.

 
 

-One should be able to view some freshness information about the
-translation status, either for a given page or for the whole wiki.
+The `ISTRANSLATION` and `ISTRANSLATABLE` variables can be used to
+display things only on translatable or translation pages.

 
 

-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.
+### Display page's versions in other languages

 
 

-Decide which pages are translatable
------------------------------------
+The `OTHERLANGUAGES` loop provides ways to display other languages'
+versions of the same page, and the translations' status.

 
 

-The subset of ("master") pages supporting translation must be
-configurable:
+An example of its use can be found in the default
+`templates/page.tmpl`. In case you want to customize it, the following
+variables are available inside the loop (for every page in):

 
 

-- a `[[!translatable ]]` directive, when put on a page, makes it
-  translatable
-- this [[ikiwiki/directive]] can be used with an optional `match=PageSpec`
-  argument, to render translatable a bunch of pages at once
+* `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

 
 

-Automatic PO files update
+### Display the current translation status
+
+The `PERCENTTRANSLATED` variable is set to the translation
+completeness, expressed in percent, on "slave" pages. It is used by
+the default `templates/page.tmpl`.
+
+Additional PageSpec tests

 -------------------------
 
 -------------------------
 

-Committing changes to a "master" page must:
+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|mdwn]] 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:

 
 

-1. update the POT file, the PO files for the supported languages, and
-   put them under version control
-2. trigger a refresh of the corresponding HTML 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.

 
 

-The former can be implemented as a `needsbuild` hook, which is the
-first type of hook to run after the list of files that need to be
-built is known: that is, at a time when we know which "master" page
-was modified, and thus, which POT/PO files have to be updated.
+Security
+========

 
 

-The latter can be implemented by making any "slave" page depend on the
-corresponding "master" page. The `add_depends` function can achieved
-this, if used in a FIXME hook.
+[[po/discussion]] contains a detailed security analysis of this plugin
+and its dependencies.

 
 

-UI consistency: rename "Edit" button on slave pages
----------------------------------------------------
+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.

 
 

-It may be surprising to some, after having pressed *Edit* on a wiki
-page, to end up editing a strange PO file. The *Edit* button must then
-be be renamed to *Improve translation* on "slave" pages.
+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 this additional features.
+
+Language display order
+----------------------
+
+Jonas pointed out that one might want to control the order that links to
+other languages are listed, for various reasons. Currently, there is no
+order, as `po_slave_languages` is a hash. It would need to be converted
+to an array to support this. (If twere done, twere best done quickly.)
+--[[Joey]] 

 
 

-Translation quality assurance
------------------------------
+Pagespecs
+---------

 
 

-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.
+I was suprised that, when using the map directive, a pagespec of "*"
+listed all the translated pages as well as regular pages. That can 
+make a big difference to an existing wiki when po is turned on,
+and seems generally not wanted.
+(OTOH, you do want to match translated pages by
+default when locking pages.) --[[Joey]]

 
 

-A new `cansave` type of hook would be needed to implement this.
+Edit links on untranslated pages
+--------------------------------

 
 

-Note: committing to the underlying repository is a way to bypass
-this check.
+If a page is not translated yet, the "translated" version of it
+displays wikilinks to other, existing (but not yet translated?)
+pages as edit links, as if those pages do not exist. 

 
 

-Translating online
-------------------
+That's really confusing, especially as clicking such a link
+brings up an edit form to create a new, english page.

 
 

-As PO is a wiki page type, we already have an online PO editor, that
-is ikiwiki's CGI.
+This is with po_link_to=current or negotiated. With default, it doesn't
+happen.. 

 
 

-A message-by-message interface could be implemented later, providing
-a nice way to translate offline (without VCS access) is provided.
+Also, this may only happen if the page being linked to is coming from an
+underlay, and the underlays lack translation to a given language.
+--[[Joey]] 

 
 

-Translating offline without VCS access
---------------------------------------
+Double commits of po files
+--------------------------

 
 

-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:
+When adding a new english page, the po files are created, committed,
+and then committed again. The second commit makes this change:
+
+       -"Content-Type: text/plain; charset=utf-8\n"
+       -"Content-Transfer-Encoding: ENCODING"
+       +"Content-Type: text/plain; charset=UTF-8\n"
+       +"Content-Transfer-Encoding: ENCODING\n"
+
+Same thing happens when a change to an existing page triggers a po file
+update. --[[Joey]] 
+
+Ugly messages with empty files
+------------------------------
+
+If there are empty .mdwn files, the po plugin displays some ugly messages.
+
+Translation of directives
+-------------------------

 
 

-- download the PO file for the page
-- use any PO editor to update the translation
-- upload the updated PO file
+If a translated page contains a directive, it may expand to some english
+text, or text in whatever single language ikiwiki is configured to "speak".

 
 

-A generic mechanism to download and upload a page's source is needed.
-It's only an alternative way to do Edit/edit/Save.
+Maybe there could be a way to switch ikiwiki to speaking another language
+when building a non-english page? Then the directives would get translated.

 
 

-### Short-term workflow
+(We also will need this in order to use translated templates, when they are
+available.)

 
 

-- 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.
+Documentation
+-------------

 
 

+Maybe write separate documentation depending on the people it targets:
+translators, wiki administrators, hackers. This plugin may be complex
+enough to deserve this.