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.
9 One thing to keep in mind when writing a plugin is that ikiwiki is a wiki
10 *compiler*. So plugins influence pages when they are built, not when they
11 are loaded. A plugin that inserts the current time into a page, for
12 example, will insert the build time. Also, as a compiler, ikiwiki avoids
13 rebuilding pages unless they have changed, so a plugin that prints some
14 random or changing thing on a page will generate a static page that won't
15 change until ikiwiki rebuilds the page for some other reason, like the page
20 Plugins should, when imported, call IkiWiki::hook to hook into ikiwiki's
21 processing. The function uses named parameters, and use varies depending on
22 the type of plugin being registered. Note that a plugin can call the
23 function more than once to register multiple hooks. All calls to
24 IkiWiki::hook should be passed a "type" parameter, which gives the type of
25 hook, a "id" paramter, which should be a unique string for this plugin, and
26 a "call" parameter, which is a reference to a function to call for the
29 # Writing a [[PreProcessorDirective]]
31 This is probably the most common use of a plugin.
33 IkiWiki::hook(type => "preprocess", id => "foo", call => \&preprocess);
35 Replace "foo" with the command name that will be used inside brackers for
36 the preprocessor directive.
38 Each time the directive is processed, the referenced function (`preprocess`
39 in the example above) is called, and is passed named parameters. A "page"
40 parameter gives the name of the page that embedded the preprocessor
41 directive, while a "destpage" parameter gices the name of the page the
42 content is going to (different for inlined pages). All parameters included
43 in the directive are included as named parameters as well. Whatever the
44 function returns goes onto the page in place of the directive.
48 While a plugin can call ikiwiki's error routine for a fatal error, for
49 errors that aren't intended to halt the entire wiki build, including bad
50 parameters passed to a [[PreProcessorDirective]], etc, it's better to just
51 return the error message as the output of the plugin.
55 Note that if the [[htmlscrubber]] is enabled, html in
56 [[PreProcessorDirective]] output is sanitised, which may limit what your
57 plugin can do. Also, the rest of the page content is not in html format at
58 preprocessor time. Text output by a preprocessor directive will be passed
59 through markdown (or whatever engine is used to htmlize the page) along
60 with the rest of the page.
62 # Other types of hooks
64 Beyond PreProcessorDirectives, Other types of hooks that can be used by
69 IkiWiki::hook(type => "getopt", id => "foo", call => \&getopt);
71 This allows for plugins to perform their own processing of command-line
72 options and so add options to the ikiwiki command line. It's called during
73 command line processing, with @ARGV full of any options that ikiwiki was
74 not able to process on its own. The function should process any options it
75 can, removing them from @ARGV. It should take care not to abort if it sees
76 an option it cannot process, and should just skip over those options and
81 IkiWiki::hook(type => "checkconfig", id => "foo", call => \&checkconfig);
83 This is useful if the plugin needs to check for, or modify ikiwiki's
84 configuration. It's called early in the ikiwiki startup process. The
85 function is passed no values. It's ok for the function to call
86 IkiWiki::error if something isn't configured right.
90 IkiWiki::hook(type => "filter", id => "foo", call => \&filter);
92 Runs on the raw source of a page, before anything else touches it, and can
93 make arbitrary changes. The function is passed named parameters `page` and
94 `content` and should return the filtered content.
98 IkiWiki::hook(type => "htmlize", id => "ext", call => \&filter);
100 Runs on the raw source of a page and turns it into html. The id parameter
101 specifies the filename extension that a file must have to be htmlized using
102 this plugin. This is how you can add support for new and exciting markup
103 languages to ikiwiki.
107 IkiWiki::hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
109 Each time a page is rendered, a [[template|templates]] is filled out.
110 This hook allows modifying that template. The function is passed named
111 parameters. The "page" and "destpage" parameters are the same as for a
112 preprocess hook. The "template" parameter is a `HTML::Template` object that
113 is the template that will be used to generate the page. The function
114 can manipulate that template object.
116 The most common thing to do is probably to call $template->param() to add
117 a new custom parameter to the template. Note that in order to be robust,
118 it's a good idea to check whether the template has a variable before trying
119 to set it, as setting a variable that's not present is an error.
121 if ($template->query(name => 'foo')) {
122 $template->param("foo" => "bar");
127 IkiWiki::hook(type => "sanitize", id => "foo", call => \&sanitize);
129 Use this to implement html sanitization or anything else that needs to
130 modify the content of a page after it has been fully converted to html.
131 The function is passed the page content and should return the sanitized
136 IkiWiki::hook(type => "delete", id => "foo", call => \&dele);
138 Each time a page or pages is removed from the wiki, the referenced function
139 is called, and passed the names of the source files that were removed.
143 IkiWiki::hook(type => "change", id => "foo", call => \&render);
145 Each time ikiwiki renders a change or addition (but not deletion) to the
146 wiki, the referenced function is called, and passed the names of the
147 source files that were rendered.
151 IkiWiki::hook(type => "cgi", id => "foo", call => \&cgi);
153 Use this to hook into ikiwiki's cgi script. Each registered cgi hook is
154 called in turn, and passed a CGI object. The hook should examine the
155 parameters, and if it will handle this CGI request, output a page and
156 terminate the program.
160 A plugin can access the wiki's configuration via the `%IkiWiki::config`
161 hash. The best way to understand the contents of the hash is to look at
162 [[ikiwiki.setup]], which sets the hash content to configure the wiki.
166 If your plugin needs to access data about other pages in the wiki. It can
167 use the following hashes, using a page name as the key:
169 * `%IkiWiki::links` lists the names of each page
170 that a page links to, in an array reference.
171 * `%IkiWiki::pagemtime` contains the last modification time of each page
172 * `%IkiWiki::pagectime` contains the creation time of each page
173 * `%IkiWiki::renderedfiles` contains the name of the file rendered by a
175 * `%IkiWiki::pagesources` contains the name of the source file for a page.
176 * `%IkiWiki::depends` contains a [[GlobList]] that is used to specify other
177 pages that a page depends on. If one of its dependencies is updated, the
178 page will also get rebuilt.
180 Many plugins will need to add dependencies to this hash; the best way to do
181 it is by using the IkiWiki::add_depends function, which takes as its
182 parameters the page name and a [[GlobList]] of dependencies to add.
184 # A note on generating html links
186 Many plugins need to generate html links and add them to a page. This is
187 done by using the `IkiWiki::htmllink` function. The usual way to call
190 htmllink($page, $page, $link)
192 Why is $page repeated? Because if a page is inlined inside another, and a
193 link is placed on it, the right way to make that link is actually:
195 htmllink($page, $destpage, $link)
197 Here $destpage is the inlining page. A destpage parameter is passed to some
198 of the hook functions above; the ones that are not passed it are not used
199 during inlining and don't need to worry about this issue.
203 ikiwiki's support for revision control systems also uses pluggable perl
204 modules. These are in the `IkiWiki::RCS` namespace, for example
207 Each RCS plugin must support all the IkiWiki::rcs\_* functions.
208 See IkiWiki::RCS::Stub for the full list of functions. It's ok if
209 rcs\_getctime does nothing except for throwing an error.
211 See [[about_RCS_backends]] for some more info.