-ikiwiki [[plugins]] are written in perl. Each plugin is a perl module, in
-the `IkiWiki::Plugin` namespace. The name of the plugin is typically in
-lowercase, such as `IkiWiki::Plugin::inline`. Ikiwiki includes a
-`IkiWiki::Plugin::skeleton` that can be fleshed out to make a useful
-plugin. `IkiWiki::Plugin::pagecount` is another simple example.
+Ikiwiki's plugin interface allows all kinds of useful [[plugins]] to be
+written to extend ikiwiki in many ways. Despite the length of this page,
+it's not really hard. This page is a complete reference to everything a
+plugin might want to do. There is also a quick [[tutorial]].
[[toc levels=2]]
+## Types of plugins
+
+Most ikiwiki [[plugins]] are written in perl, like ikiwiki. This gives the
+plugin full access to ikiwiki's internals, and is the most efficient.
+However, plugins can actually be written in any language that supports XML
+RPC. These are called [[external]] plugins.
+
+A plugin written in perl is a perl module, in the `IkiWiki::Plugin`
+namespace. The name of the plugin is typically in lowercase, such as
+`IkiWiki::Plugin::inline`. Ikiwiki includes a `IkiWiki::Plugin::skeleton`
+that can be fleshed out to make a useful plugin.
+`IkiWiki::Plugin::pagecount` is another simple example. All perl plugins
+should `use IkiWiki` to import the ikiwiki plugin interface. It's a good
+idea to include the version number of the plugin interface that your plugin
+expects: `use IkiWiki 2.00`.
+
+An external plugin is an executable program. It can be written in any
+language. Its interface to ikiwiki is via XML RPC, which it reads from
+ikiwiki on its standard input, and writes to ikiwiki on its standard
+output. For more details on writing external plugins, see [[external]].
+
+Despite these two types of plugins having such different interfaces,
+they're the same as far as how they hook into ikiwiki. This document will
+explain how to write both sorts of plugins, albeit with an emphasis on perl
+plugins.
+
## Considerations
One thing to keep in mind when writing a plugin is that ikiwiki is a wiki
## Registering plugins
-All plugins should `use IkiWiki` to import the ikiwiki plugin interface.
-
Plugins should, when imported, call `hook()` to hook into ikiwiki's
processing. The function uses named parameters, and use varies depending on
the type of hook being registered -- see below. Note that a plugin can call
the function more than once to register multiple hooks. All calls to
`hook()` should be passed a "type" parameter, which gives the type of
hook, a "id" paramter, which should be a unique string for this plugin, and
-a "call" parameter, which is a reference to a function to call for the
-hook.
-
-An optional "scan" parameter, if set to a true value, makes the hook be
-called during the preliminary scan that ikiwiki makes of updated pages,
-before begining to render pages. This parameter should be set to true if
-the hook modifies data in `%links`. Note that doing so will make the hook
-be run twice per page build, so avoid doing it for expensive hooks.
+a "call" parameter, which tells what function to call for the hook.
An optional "last" parameter, if set to a true value, makes the hook run
after all other hooks of its type. Useful if the hook depends on some other
function is passed no values. It's ok for the function to call
`error()` if something isn't configured right.
-### filter
+### needsbuild
- hook(type => "filter", id => "foo", call => \&filter);
+ hook(type => "needsbuild", id => "foo", call => \&needsbuild);
-Runs on the raw source of a page, before anything else touches it, and can
-make arbitrary changes. The function is passed named parameters `page` and
-`content` and should return the filtered content.
+This allows a plugin the manipulate the list of files that need to be
+built when the wiki is refreshed. The function is passed a reference to an
+array of pages that will be rebuilt, and can modify the array, either
+adding or removing files from it.
-### scan
+### filter
- hook(type => "scan", id => "foo", call => \&scan);
+ hook(type => "filter", id => "foo", call => \&filter);
-This is identical to a preprocess hook (see below), except that it is
-called in the initial pass that scans pages for data that will be used in
-later passes. Scan hooks are the only hook that should modify `%links`.
+Runs on the raw source of a page, before anything else touches it, and can
+make arbitrary changes. The function is passed named parameters "page",
+"destpage", and "content". It should return the filtered content.
### preprocess
well. Whatever the function returns goes onto the page in place of the
directive.
+An optional "scan" parameter, if set to a true value, makes the hook be
+called during the preliminary scan that ikiwiki makes of updated pages,
+before begining to render pages. This parameter should be set to true if
+the hook modifies data in `%links`. Note that doing so will make the hook
+be run twice per page build, so avoid doing it for expensive hooks.
+
Note that if the [[htmlscrubber]] is enabled, html in
[[PreProcessorDirective]] output is sanitised, which may limit what your
plugin can do. Also, the rest of the page content is not in html format at
hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
-[[Templates]] are filled out for many different things in ikiwiki, like
-generating a page, or part of a blog page, or an rss feed, or a cgi. This
-hook allows modifying those templates. The function is passed named
-parameters. The "page" and "destpage" parameters are the same as for a
-preprocess hook. The "template" parameter is a [[cpan HTML::Template]]
-object that is the template that will be used to generate the page. The
-function can manipulate that template object.
+[[Templates|wikitemplates]] are filled out for many different things in
+ikiwiki, like generating a page, or part of a blog page, or an rss feed, or
+a cgi. This hook allows modifying the variables available on those
+templates. The function is passed named parameters. The "page" and
+"destpage" parameters are the same as for a preprocess hook. The "template"
+parameter is a [[cpan HTML::Template]] object that is the template that
+will be used to generate the page. The function can manipulate that
+template object.
-The most common thing to do is probably to call $template->param() to add
+The most common thing to do is probably to call `$template->param()` to add
a new custom parameter to the template.
+### templatefile
+
+ hook(type => "templatefile", id => "foo", call => \&templatefile);
+
+This hook allows plugins to change the [[template|wikitemplate]] that is
+used for a page in the wiki. The hook is passed a "page" parameter, and
+should return the name of the template file to use, or undef if it doesn't
+want to change the default ("page.tmpl"). Template files are looked for in
+/usr/share/ikiwiki/templates by default.
+
### sanitize
hook(type => "sanitize", id => "foo", call => \&sanitize);
Use this to hook into ikiwiki's cgi script. Each registered cgi hook is
called in turn, and passed a CGI object. The hook should examine the
-parameters, and if it will handle this CGI request, output a page and
+parameters, and if it will handle this CGI request, output a page (including the http headers) and
terminate the program.
### auth
if the name is set to the name of a user who is not registered,
a basic registration of the user will be automatically performed.
+### sessioncgi
+
+ hook(type => "sessioncgi", id => "foo", call => \&sessioncgi);
+
+Unlike the cgi hook, which is run as soon as possible, the sessioncgi hook
+is only run once a session object is available. It is passed both a CGI
+object and a session object. To check if the user is in fact signed in, you
+can check if the session object has a "name" parameter set.
+
### canedit
hook(type => "canedit", id => "foo", call => \&pagelocked);
These hooks allow tapping into the parts of ikiwiki that use [[cpan
CGI::FormBuilder]] to generate web forms. These hooks are passed named
-parameters: `cgi`, `session`, and `form`. These are, respectively, the
-`CGI` object, the user's `CGI::Session`, and a `CGI::FormBuilder`.
+parameters: `cgi`, `session`, `form`, and `buttons`. These are, respectively,
+the `CGI` object, the user's `CGI::Session`, a `CGI::FormBuilder`, and a
+reference to an array of names of buttons to go on the form.
Each time a form is set up, the `formbuilder_setup` hook is called.
Typically the `formbuilder_setup` hook will check the form's title, and if
Form validation and display can be overridden by the formbuilder hook.
By default, ikiwiki will do a basic validation and display of the form,
but if this hook is registered, it will stop that and let the hook take
-over. This hook is passed an additional named parameter: `buttons` is an
-array of the submit buttons for the form.
+over.
### savestate
and a special effort will be made to avoid changing them in incompatible
ways, and to document any changes that have to be made in the future.
-Note that IkiWiki also provides other variables functions that are not
+Note that IkiWiki also provides other variables and functions that are not
exported by default. No guarantee is made about these in the future, so if
it's not exported, the wise choice is to not use it.
If your plugin needs to access data about other pages in the wiki. It can
use the following hashes, using a page name as the key:
-* `links` lists the names of each page that a page links to, in an array
+* `%links` lists the names of each page that a page links to, in an array
reference.
* `%destsources` contains the name of the source file used to create each
destination file.
Hook into ikiwiki's processing. See the discussion of hooks above.
Note that in addition to the named parameters described above, a parameter
-named no_override is supported, If it's set to a true value, then this hook
+named `no_override` is supported, If it's set to a true value, then this hook
will not override any existing hook with the same id. This is useful if
the id can be controled by the user.
Creates and returns a [[cpan HTML::Template]] object. The first parameter
is the name of the file in the template directory. The optional remaining
-parameters are passed to HTML::Template->new.
+parameters are passed to `HTML::Template->new`.
#### `htmlpage($)`
Makes the specified page depend on the specified [[PageSpec]].
-#### `pagespec_match($$;$)`
+#### `pagespec_match($$;@)`
+
+Passed a page name, and [[PageSpec]], returns true if the [[PageSpec]]
+matches the page.
-Passed a page name, a [[PageSpec]], and the location the [[PageSpec]] should
-be matched against, returns true if the [[PageSpec]] matches the page. (If
-the third parameter is not passed, relative PageSpecs will match relative to
-the top of the wiki.)
+Additional named parameters can be passed, to further limit the match.
+The most often used is "location", which specifies the location the
+PageSpec should match against. If not passed, relative PageSpecs will match
+relative to the top of the wiki.
#### `bestlink($$)`
* forcesubpage - set to force a link to a subpage
* linktext - set to force the link text to something
* anchor - set to make the link include an anchor
+* rel - set to add a rel attribute to the link.
#### `readfile($;$)`
If the destination directory doesn't exist, it will first be created.
-### `will_render($$)`
+#### `will_render($$)`
Given a page name and a destination file name (not including the base
destination directory), register that the page will result in that file
#### `urlto($$)`
-Construct a relative url to the first parameter from the second.
+Construct a relative url to the first parameter from the page named by the
+second. The first parameter can be either a page name, or some other
+destination file, as registered by `will_render`.
#### `targetpage($$)`
## RCS plugins
-ikiwiki's support for revision control systems also uses pluggable perl
-modules. These are in the `IkiWiki::RCS` namespace, for example
+ikiwiki's support for [[revision_control_systems|rcs]] also uses pluggable
+perl modules. These are in the `IkiWiki::RCS` namespace, for example
`IkiWiki::RCS::svn`.
-Each RCS plugin must support all the IkiWiki::rcs\_* functions.
+Each RCS plugin must support all the `IkiWiki::rcs_*` functions.
See IkiWiki::RCS::Stub for the full list of functions. It's ok if
-rcs\_getctime does nothing except for throwing an error.
+`rcs_getctime` does nothing except for throwing an error.
-See [[about_RCS_backends]] for some more info.
+See [[RCS_details|rcs/details]] for some more info.
## PageSpec plugins
[[PageSpecs|PageSpec]]. Such a plugin should add a function to the
IkiWiki::PageSpec package, that is named `match_foo`, where "foo()" is
how it will be accessed in a [[PageSpec]]. The function will be passed
-three parameters: The name of the page being matched, the thing to match
-against, and the page that the matching is occuring on. It should return
-true if the page matches.
+two parameters: The name of the page being matched, and the thing to match
+against. It may also be passed additional, named parameters. It should return
+a IkiWiki::SuccessReason object if the match succeeds, or an
+IkiWiki::FailReason object if the match fails.