`IkiWiki::Plugin::skeleton` that can be fleshed out to make a useful
plugin. `IkiWiki::Plugin::pagecount` is another simple example.
-## Note
+# Note
One thing to keep in mind when writing a plugin is that ikiwiki is a wiki
*compiler*. So plugins influence pages when they are built, not when they
change until ikiwiki rebuilds the page for some other reason, like the page
being edited.
-## Registering plugins
+# Registering plugins
-Plugins should, when imported, call IkiWiki::hook to hook into
-ikiwiki's processing. The function uses named parameters, and use varies depending on the type of plugin being registered. Note that a plugin can call the function more than once to register multiple hooks. All calls to IkiWiki::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.
+Plugins should, when imported, call IkiWiki::hook to hook into ikiwiki's
+processing. The function uses named parameters, and use varies depending on
+the type of plugin being registered. Note that a plugin can call the
+function more than once to register multiple hooks. All calls to
+IkiWiki::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.
-## Writing a [[PreProcessorDirective]]
+# Writing a [[PreProcessorDirective]]
This is probably the most common use of a plugin.
IkiWiki::hook(type => "preprocess", id => "foo", call => \&preprocess);
-Replace "foo" with the command name that will be used inside brackers for the preprocessor directive.
+Replace "foo" with the command name that will be used inside brackers for
+the preprocessor directive.
-Each time the directive is processed, the referenced function (`preprocess` in the example above) is called, and is passed named parameters. A
-"page" parameter gives the name of the page that embedded the preprocessor directive. All parameters included in the directive are included
-as named parameters as well. Whatever the function returns goes onto the
-page in place of the directive.
+Each time the directive is processed, the referenced function (`preprocess`
+in the example above) is called, and is passed named parameters. A "page"
+parameter gives the name of the page that embedded the preprocessor
+directive, while a "destpage" parameter gices the name of the page the
+content is going to (different for inlined pages). All parameters included
+in the directive are included as named parameters as well. Whatever the
+function returns goes onto the page in place of the directive.
-## Other types of hooks
+## Error handing
-Beyond PreProcessorDirectives, Other types of hooks that can be used by plugins include:
+While a plugin can call ikiwiki's error routine for a fatal error, for
+errors that aren't intended to halt the entire wiki build, including bad
+parameters passed to a [[PreProcessorDirective]], etc, it's better to just
+return the error message as the output of the plugin.
-### delete
+## Html issues
- IkiWiki::hook(type => "delete", id => "foo", call => \&deletion);
+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
+preprocessor time. Text output by a preprocessor directive will be passed
+through markdown (or whatever engine is used to htmlize the page) along
+with the rest of the page.
-Each time a page or pages is removed from the wiki, the referenced function is called, and passed the names of the source files that were removed.
+# Other types of hooks
-### render
+Beyond PreProcessorDirectives, Other types of hooks that can be used by
+plugins include:
- IkiWiki::hook(type => "render", id => "foo", call => \&update);
+## checkconfig
-Each time ikiwiki renders a change or addition (but not deletion) of a page to the wiki, the referenced function is called, and passed the name of the source file that was rendered.
+ IkiWiki::hook(type => "checkconfig", id => "foo", call => \&checkconfig);
-## Error handing in plugins
+This is useful if the plugin needs to check for, or modify ikiwiki's
+configuration. It's called early in the ikiwiki startup process. The
+function is passed no values. It's ok for the function to call
+IkiWiki::error if something isn't configured right.
-While a plugin can call ikiwiki's error routine for a fatal error, for
-errors that aren't intended to halt the entire wiki build, including bad
-parameters passed to a [[PreProcessorDirective]], etc, it's better to just
-return the error message as the output of the plugin.
+## filter
-## Html issues
+ IkiWiki::hook(type => "filter", id => "foo", call => \&filter);
-Note that if [[HTMLSanitization]] 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
-preprocessor time. Text output by a preprocessor directive will be passed through markdown along with the rest of the page.
+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.
+
+## htmlize
+
+ IkiWiki::hook(type => "htmlize", id => "ext", call => \&filter);
+
+Runs on the raw source of a page and turns it into html. The id parameter
+specifies the filename extension that a file must have to be htmlized using
+this plugin. This is how you can add support for new and exciting markup
+languages to ikiwiki.
+
+## pagetemplate
+
+ IkiWiki::hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
+
+Each time a page is rendered, a [[template|templates]] is filled out.
+This hook allows modifying that template. The function is passed named
+parameters. The "page" and "destpage" parameters are the same as for a
+preprocess hook. The "template" parameter is a `HTML::Template` object that
+is the template that will be used to generate the page. The function
+can manipulate that template object.
-## Wiki configuration
+The most common thing to do is probably to call $template->param() to add
+a new custom parameter to the template. Note that in order to be robust,
+it's a good idea to check whether the template has a variable before trying
+to set it, as setting a variable that's not present is an error.
-A plugin can access the wiki's configuration via the `%IkiWiki::config` hash.
-The best way to understand the contents of the hash is to look at
+ if ($template->query(name => 'foo')) {
+ $template->param("foo" => "bar");
+ }
+
+## sanitize
+
+ IkiWiki::hook(type => "sanitize", id => "foo", call => \&sanitize);
+
+Use this to implement html sanitization or anything else that needs to
+modify the content of a page after it has been fully converted to html.
+The function is passed the page content and should return the sanitized
+content.
+
+## delete
+
+ IkiWiki::hook(type => "delete", id => "foo", call => \&dele);
+
+Each time a page or pages is removed from the wiki, the referenced function
+is called, and passed the names of the source files that were removed.
+
+## change
+
+ IkiWiki::hook(type => "change", id => "foo", call => \&render);
+
+Each time ikiwiki renders a change or addition (but not deletion) to the
+wiki, the referenced function is called, and passed the names of the
+source files that were rendered.
+
+## cgi
+
+ IkiWiki::hook(type => "cgi", id => "foo", call => \&cgi);
+
+Use this to hook into ikiwiki's cgi script. Each registered cgi hook is
+called in turn, and passed a CGI object. The hook should examine the
+parameters, and if it will handle this CGI request, output a page and
+terminate the program.
+
+# Wiki configuration
+
+A plugin can access the wiki's configuration via the `%IkiWiki::config`
+hash. The best way to understand the contents of the hash is to look at
[[ikiwiki.setup]], which sets the hash content to configure the wiki.
-## Wiki data
+# Wiki data
If your plugin needs to access data about other pages in the wiki. It can
use the following hashes, using a page name as the key:
it is by using the IkiWiki::add_depends function, which takes as its
parameters the page name and a [[GlobList]] of dependencies to add.
-## RCS plugins
+# A note on generating html links
+
+Many plugins need to generate html links and add them to a page. This is
+done by using the htmllink() function in ikiwiki. The usual way to call
+htmlllink is: `htmllink($page, $page, $link)`
+
+Why is $page repeated? Because if a page is inlined inside another, and a
+link is placed on it, the right way to make that link is actually:
+`htmllink($page, $destpage, $link)`
+
+Here $destpage is the inlining page. A destpage parameter is passed to some
+of the hook functions above; the ones that are not passed it are not used
+during inlining and don't need to worry about this issue.
+
+# RCS plugins
ikiwiki's support for revision control systems 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.