1 ikiwiki [[plugins]] are written in perl. Each plugin is a perl module, in
2 the `IkiWiki::Plugin` namespace. The name of the plugin is typically in
3 lowercase, such as `IkiWiki::Plugin::inline`. Ikiwiki includes a
4 `IkiWiki::Plugin::skeleton` that can be fleshed out to make a useful
5 plugin. `IkiWiki::Plugin::pagecount` is another simple example.
11 One thing to keep in mind when writing a plugin is that ikiwiki is a wiki
12 *compiler*. So plugins influence pages when they are built, not when they
13 are loaded. A plugin that inserts the current time into a page, for
14 example, will insert the build time. Also, as a compiler, ikiwiki avoids
15 rebuilding pages unless they have changed, so a plugin that prints some
16 random or changing thing on a page will generate a static page that won't
17 change until ikiwiki rebuilds the page for some other reason, like the page
20 ## Registering plugins
22 All plugins should `use IkiWiki` to import the ikiwiki plugin interface.
24 Plugins should, when imported, call `hook()` to hook into ikiwiki's
25 processing. The function uses named parameters, and use varies depending on
26 the type of hook being registered -- see below. Note that a plugin can call
27 the function more than once to register multiple hooks. All calls to
28 `hook()` should be passed a "type" parameter, which gives the type of
29 hook, a "id" paramter, which should be a unique string for this plugin, and
30 a "call" parameter, which is a reference to a function to call for the
33 An optional "scan" parameter, if set to a true value, makes the hook be
34 called during the preliminary scan that ikiwiki makes of updated pages,
35 before begining to render pages. This parameter should be set to true if
36 the hook modifies data in `%links`. Note that doing so will make the hook
37 be run twice per page build, so avoid doing it for expensive hooks.
39 An optional "last" parameter, if set to a true value, makes the hook run
40 after all other hooks of its type. Useful if the hook depends on some other
45 In roughly the order they are called.
49 hook(type => "getopt", id => "foo", call => \&getopt);
51 This allows for plugins to perform their own processing of command-line
52 options and so add options to the ikiwiki command line. It's called during
53 command line processing, with @ARGV full of any options that ikiwiki was
54 not able to process on its own. The function should process any options it
55 can, removing them from @ARGV, and probably recording the configuration
56 settings in %config. It should take care not to abort if it sees
57 an option it cannot process, and should just skip over those options and
62 hook(type => "checkconfig", id => "foo", call => \&checkconfig);
64 This is useful if the plugin needs to check for or modify ikiwiki's
65 configuration. It's called early in the startup process. The
66 function is passed no values. It's ok for the function to call
67 `error()` if something isn't configured right.
71 hook(type => "filter", id => "foo", call => \&filter);
73 Runs on the raw source of a page, before anything else touches it, and can
74 make arbitrary changes. The function is passed named parameters `page` and
75 `content` and should return the filtered content.
79 hook(type => "scan", id => "foo", call => \&scan);
81 This is identical to a preprocess hook (see below), except that it is
82 called in the initial pass that scans pages for data that will be used in
83 later passes. Scan hooks are the only hook that should modify
87 Adding a [[PreProcessorDirective]] is probably the most common use of a
90 hook(type => "preprocess", id => "foo", call => \&preprocess);
92 Replace "foo" with the command name that will be used inside brackets for
93 the preprocessor directive.
95 Each time the directive is processed, the referenced function (`preprocess`
96 in the example above) is called, and is passed named parameters. A "page"
97 parameter gives the name of the page that embedded the preprocessor
98 directive, while a "destpage" parameter gives the name of the page the
99 content is going to (different for inlined pages). All parameters included
100 in the directive are included as named parameters as well. Whatever the
101 function returns goes onto the page in place of the directive.
103 Note that if the [[htmlscrubber]] is enabled, html in
104 [[PreProcessorDirective]] output is sanitised, which may limit what your
105 plugin can do. Also, the rest of the page content is not in html format at
106 preprocessor time. Text output by a preprocessor directive will be
107 linkified and passed through markdown (or whatever engine is used to htmlize
108 the page) along with the rest of the page.
112 hook(type => "htmlize", id => "ext", call => \&htmlize);
114 Runs on the raw source of a page and turns it into html. The id parameter
115 specifies the filename extension that a file must have to be htmlized using
116 this plugin. This is how you can add support for new and exciting markup
117 languages to ikiwiki.
119 The function is passed named parameters: "page" and "content" and should
120 return the htmlized content.
124 hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
126 [[Templates]] are filled out for many different things in ikiwiki, like
127 generating a page, or part of a blog page, or an rss feed, or a cgi. This
128 hook allows modifying those templates. The function is passed named
129 parameters. The "page" and "destpage" parameters are the same as for a
130 preprocess hook. The "template" parameter is a [[cpan HTML::Template]]
131 object that is the template that will be used to generate the page. The
132 function can manipulate that template object.
134 The most common thing to do is probably to call $template->param() to add
135 a new custom parameter to the template.
139 hook(type => "sanitize", id => "foo", call => \&sanitize);
141 Use this to implement html sanitization or anything else that needs to
142 modify the body of a page after it has been fully converted to html.
144 The function is passed named parameters: "page" and "content", and
145 should return the sanitized content.
149 hook(type => "format", id => "foo", call => \&format);
151 The difference between format and sanitize is that sanitize only acts on
152 the page body, while format can modify the entire html page including the
153 header and footer inserted by ikiwiki, the html document type, etc.
155 The function is passed named parameters: "page" and "content", and
156 should return the formatted content.
160 hook(type => "delete", id => "foo", call => \&delete);
162 Each time a page or pages is removed from the wiki, the referenced function
163 is called, and passed the names of the source files that were removed.
167 hook(type => "change", id => "foo", call => \&render);
169 Each time ikiwiki renders a change or addition (but not deletion) to the
170 wiki, the referenced function is called, and passed the names of the
171 source files that were rendered.
175 hook(type => "cgi", id => "foo", call => \&cgi);
177 Use this to hook into ikiwiki's cgi script. Each registered cgi hook is
178 called in turn, and passed a CGI object. The hook should examine the
179 parameters, and if it will handle this CGI request, output a page and
180 terminate the program.
184 hook(type => "auth", id => "foo", call => \&auth);
186 This hook can be used to implement a different authentication method than
187 the standard web form. When a user needs to be authenticated, each registered
188 auth hook is called in turn, and passed a CGI object and a session object.
190 If the hook is able to authenticate the user, it should set the session
191 object's "name" parameter to the authenticated user's name. Note that
192 if the name is set to the name of a user who is not registered,
193 a basic registration of the user will be automatically performed.
197 hook(type => "canedit", id => "foo", call => \&pagelocked);
199 This hook can be used to implement arbitrary access methods to control when
200 a page can be edited using the web interface (commits from revision control
201 bypass it). When a page is edited, each registered canedit hook is called
202 in turn, and passed the page name, a CGI object, and a session object.
204 If edit can proceed, the hook should return "". If the edit is not allowed
205 by this hook, the hook should return an error message for the user to see.
206 If the hook has no opinion about whether the edit can proceed, return
207 `undef`, and the next plugin will be asked to decide.
211 hook(type => "formbuilder_setup", id => "foo", call => \&formbuilder_setup);
212 hook(type => "formbuilder", id => "foo", call => \&formbuilder);
214 These hooks allow tapping into the parts of ikiwiki that use [[cpan
215 CGI::FormBuilder]] to generate web forms. These hooks are passed named
216 parameters: `cgi`, `session`, and `form`. These are, respectively, the
217 `CGI` object, the user's `CGI::Session`, and a `CGI::FormBuilder`.
219 Each time a form is set up, the formbuilder_setup hook is called.
220 Typically the formbuilder_setup hook will check the form's title, and if
221 it's a form that it needs to modify, will call various methods to
222 add/remove/change fields, tweak the validation code for the fields, etc. It
223 will not validate or display the form.
225 Form validation and display can be overridden by the formbuilder hook.
226 By default, ikiwiki will do a basic validation and display of the form,
227 but if this hook is registered, it will stop that and let the hook take
228 over. This hook is passed an additional named parameter: `buttons` is an
229 array of the submit buttons for the form.
233 hook(type => "savestate", id => "foo", call => \&savestate);
235 This hook is called wheneven ikiwiki normally saves its state, just before
236 the state is saved. The function can save other state, modify values before
241 To import the ikiwiki plugin interface:
245 This will import several variables and functions into your plugin's
246 namespace. These variables and functions are the ones most plugins need,
247 and a special effort will be made to avoid changing them in incompatible
248 ways, and to document any changes that have to be made in the future.
250 Note that IkiWiki also provides other variables functions that are not
251 exported by default. No guarantee is made about these in the future, so if
252 it's not exported, the wise choice is to not use it.
256 A plugin can access the wiki's configuration via the `%config`
257 hash. The best way to understand the contents of the hash is to look at
258 [[ikiwiki.setup]], which sets the hash content to configure the wiki.
262 If your plugin needs to access data about other pages in the wiki. It can
263 use the following hashes, using a page name as the key:
265 * `%links` lists the names of each page that a page links to, in an array
267 * `%renderedfiles` lists names of the files rendered by a page, in an array
269 * `%pagesources` contains the name of the source file for a page.
271 Also, the %IkiWiki::version variable contains the version number for the
274 ### Library functions
278 Hook into ikiwiki's processing. See the discussion of hooks above.
280 Note that in addition to the named parameters described above, a parameter
281 named no_override is supported, If it's set to a true value, then this hook
282 will not override any existing hook with the same id. This is useful if
283 the id can be controled by the user.
287 Logs a debugging message. These are supressed unless verbose mode is turned
292 Aborts with an error message. If the second parameter is passed, it is a
293 function that is called after the error message is printed, to do any final
296 Note that while any plugin can use this for a fatal error, plugins should
297 try to avoid dying on bad input, as that will halt the entire wiki build
298 and make the wiki unusable. So for example, if a [[PreProcessorDirective]]
299 is passed bad parameters, it's better to return an error message, which can
300 appear on the wiki page, rather than calling error().
304 Creates and returns a [[cpan HTML::Template]] object. The first parameter
305 is the name of the file in the template directory. The optional remaining
306 parameters are passed to HTML::Template->new.
310 Passed a page name, returns the base name that will be used for a the html
311 page created from it. (Ie, it appends ".html".)
313 #### `add_depends($$)`
315 Makes the specified page depend on the specified [[PageSpec]].
317 #### `pagespec_match($$;$)`
319 Passed a page name, a [[PageSpec]], and the location the [[PageSpec]] should
320 be matched against, returns true if the [[PageSpec]] matches the page. (If
321 the third parameter is not passed, relative PageSpecs will match relative to
322 the top of the wiki.)
326 Given a page and the text of a link on the page, determine which
327 existing page that link best points to. Prefers pages under a
328 subdirectory with the same name as the source page, failing that
329 goes down the directory tree to the base looking for matching
330 pages, as described in [[SubPage/LinkingRules]].
332 #### `htmllink($$$;@)`
334 Many plugins need to generate html links and add them to a page. This is
335 done by using the `htmllink` function. The usual way to call
338 htmllink($page, $page, $link)
340 Why is `$page` repeated? Because if a page is inlined inside another, and a
341 link is placed on it, the right way to make that link is actually:
343 htmllink($page, $destpage, $link)
345 Here `$destpage` is the inlining page. A `destpage` parameter is passed to
346 some of the hook functions above; the ones that are not passed it are not used
347 during inlining and don't need to worry about this issue.
349 After the three required parameters, named parameters can be used to
350 control some options. These are:
352 * noimageinline - set to true to avoid turning links into inline html images
353 * forcesubpage - set to force a link to a subpage
354 * linktext - set to force the link text to something
355 * anchor - set to make the link include an anchor
359 Given a filename, reads and returns the entire file.
361 The optional second parameter, if set to a true value, makes the file be read
364 A failure to read the file will result in it dying with an error.
366 #### `writefile($$$;$$)`
368 Given a filename, a directory to put it in, and the file's content,
371 The optional fourth parameter, if set to a true value, makes the file be
372 written in binary mode.
374 The optional fifth parameter can be used to pass a function reference that
375 will be called to handle writing to the file. The function will be called
376 and passed a file descriptor it should write to, and an error recovery
377 function it should call if the writing fails. (You will not normally need to
380 A failure to write the file will result in it dying with an error.
382 If the destination directory doesn't exist, it will first be created.
384 ### `will_render($$)`
386 Given a page name and a destination file name (not including the base
387 destination directory), register that the page will result in that file
388 being rendered. It's important to call this before writing to any file in
389 the destination directory.
393 Given the name of a source file, returns the type of page it is, if it's
394 a type that ikiwiki knowns how to htmlize. Otherwise, returns undef.
398 Given the name of a source file, returns the name of the wiki page
399 that corresponds to that file.
403 Given the name of a source file in the wiki, searches for the file in
404 the source directory and the underlay directory, and returns the full
405 path to the first file found.
407 #### `displaytime($)`
409 Given a time, formats it for display.
413 This is the standard gettext function, although slightly optimised.
417 ikiwiki's support for revision control systems also uses pluggable perl
418 modules. These are in the `IkiWiki::RCS` namespace, for example
421 Each RCS plugin must support all the IkiWiki::rcs\_* functions.
422 See IkiWiki::RCS::Stub for the full list of functions. It's ok if
423 rcs\_getctime does nothing except for throwing an error.
425 See [[about_RCS_backends]] for some more info.
429 It's also possible to write plugins that add new functions to
430 [[PageSpecs|PageSpec]]. Such a plugin should add a function to the
431 IkiWiki::PageSpec package, that is named `match_foo`, where "foo()" is
432 how it will be accessed in a [[PageSpec]]. The function will be passed two
433 parameters: The name of the page being matched, and the thing to match
434 against. It should return true if the page matches.