X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/54d5308cd83c67e7e9c32450c776ef0dac63549f..299bb8bef3811b16d29a0e8ebb2c292c8dd11020:/doc/plugins/write.mdwn diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn index e09ca3510..93c6d1d5c 100644 --- a/doc/plugins/write.mdwn +++ b/doc/plugins/write.mdwn @@ -4,7 +4,7 @@ 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. -## 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 @@ -15,25 +15,35 @@ random or changing thing on a page will generate a static page that won't 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::register_plugin to hook into -ikiwiki. The function takes four parameters: +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. -1. A method type. Use "preprocess" to register a [[PreProcessorDirective]] -2. A command name. This is the bit that will appear inside brackets in a - page. -3. A reference to a subroutine that is run when the plugin is used. +# Writing a [[PreProcessorDirective]] -## Writing a [[PreProcessorDirective]] +This is probably the most common use of a plugin. -For preprocessor commands, the subroutine is passed named parameters. A -"page" parameter gives the name of the page that embedded the preprocessor -command. All parameters included in the preprocessor command are included -as named parameters as well. Whatever the subroutine returns goes onto the -page in place of the command. + IkiWiki::hook(type => "preprocess", id => "foo", call => \&preprocess); -## Error handing in plugins +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, 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. + +## Error handing 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 @@ -42,26 +52,126 @@ return the error message as the output of the plugin. ## Html issues -Note that if [[HTMLSanitization]] is enabled, html in +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. +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. + +# Other types of hooks + +Beyond PreProcessorDirectives, Other types of hooks that can be used by +plugins include: + +## getopt + + IkiWiki::hook(type => "getopt", id => "foo", call => \&getopt); + +This allows for plugins to perform their own processing of command-line +options and so add options to the ikiwiki command line. It's called during +command line processing, with @ARGV full of any options that ikiwiki was +not able to process on its own. The function should process any options it +can, removing them from @ARGV, and probably recording the configuration +settings in %IkiWiki::config. It should take care not to abort if it sees +an option it cannot process, and should just skip over those options and +leave them in @ARGV. + +## checkconfig + + IkiWiki::hook(type => "checkconfig", id => "foo", call => \&checkconfig); + +This is useful if the plugin needs to check for or modify ikiwiki's +configuration. It's called early in the startup process. The +function is passed no values. It's ok for the function to call +IkiWiki::error if something isn't configured right. + +## filter + + IkiWiki::hook(type => "filter", id => "foo", call => \&filter); + +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 (or part of a blog page, or an rss feed) 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. + +The most common thing to do is probably to call $template->param() to add +a new custom parameter to the template. Note that in order to be robust, +it's a good idea to check whether the template has a variable before trying +to set it, as setting a variable that's not present is an error. + + if ($template->query(name => 'foo')) { + $template->param("foo" => "bar"); + } + +## sanitize -## Wiki configuration + IkiWiki::hook(type => "sanitize", id => "foo", call => \&sanitize); -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 +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: * `%IkiWiki::links` lists the names of each page - that is linked to from that page in an array reference. + that a page links to, in an array reference. * `%IkiWiki::pagemtime` contains the last modification time of each page -* `%IkiWiki::pagectime` contains the creation time of each page` +* `%IkiWiki::pagectime` contains the creation time of each page * `%IkiWiki::renderedfiles` contains the name of the file rendered by a page * `%IkiWiki::pagesources` contains the name of the source file for a page. @@ -72,3 +182,32 @@ use the following hashes, using a page name as the key: Many plugins will need to add dependencies to this hash; the best way to do it is by using the IkiWiki::add_depends function, which takes as its parameters the page name and a [[GlobList]] of dependencies to add. + +# 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 `IkiWiki::htmllink` function. 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. +See IkiWiki::RCS::Stub for the full list of functions. It's ok if +rcs\_getctime does nothing except for throwing an error. + +See [[about_RCS_backends]] for some more info.