X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/1478bab0cdf13b0a1ed09e5247bada907d245a47..aa2b3b8f637d0f3abe2ebf3845a22781ffd83c72:/doc/plugins/write.mdwn diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn index 165627f99..dd0ab451f 100644 --- a/doc/plugins/write.mdwn +++ b/doc/plugins/write.mdwn @@ -4,7 +4,9 @@ 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 +[[toc levels=2]] + +## Considerations 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 @@ -17,56 +19,165 @@ being edited. ## 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. + +## Types of hooks + +In roughly the order they are called. + +### 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. -## Writing a [[PreProcessorDirective]] +### preprocess -This is probably the most common use of a plugin. +Adding a [[PreProcessorDirective]] 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 brackets 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. + +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 +linkified and passed through markdown (or whatever engine is used to htmlize +the page) along with the rest of the page. + +### htmlize + + IkiWiki::hook(type => "htmlize", id => "ext", call => \&htmlize); + +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. + +The function is passed named parameters: "page" and "content" and should +return the htmlized content. + +### 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. -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. +The most common thing to do is probably to call $template->param() to add +a new custom parameter to the template. -## Other types of hooks +### sanitize -Beyond PreProcessorDirectives, Other types of hooks that can be used by plugins include: + IkiWiki::hook(type => "sanitize", id => "foo", call => \&sanitize); + +Use this to implement html sanitization or anything else that needs to +modify the body of a page after it has been fully converted to html. + +The function is passed named parameters: "page" and "content", and +should return the sanitized content. + +### format + + IkiWiki::hook(type => "format", id => "foo", call => \&format); + +The difference between format and sanitize is that sanitize only acts on +the page body, while format can modify the entire html page including the +header and footer inserted by ikiwiki, the html document type, etc. + +The function is passed named parameters: "page" and "content", and +should return the formatted content. ### delete - IkiWiki::hook(type => "delete", id => "foo", call => \&deletion); + IkiWiki::hook(type => "delete", id => "foo", call => \&delete); + +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); -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. +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. -### render +### savestate - IkiWiki::hook(type => "render", id => "foo", call => \&update); + IkiWiki::hook(type => "savestate", id => "foo", call => \&savestate); -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. +This hook is called wheneven ikiwiki normally saves its state, just before +the state is saved. The function can save other state, modify values before +they're saved, etc. -## Error handing in plugins +## Error handing -While a plugin can call ikiwiki's error routine for a fatal error, for +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. -## Html issues - -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. - ## 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 +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 @@ -81,13 +192,32 @@ use the following hashes, using a page name as the key: * `%IkiWiki::renderedfiles` contains the name of the file rendered by a page * `%IkiWiki::pagesources` contains the name of the source file for a page. -* `%IkiWiki::depends` contains a [[GlobList]] that is used to specify other +* `%IkiWiki::depends` contains a [[PageSpec]] that is used to specify other pages that a page depends on. If one of its dependencies is updated, the page will also get rebuilt. 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. + parameters the page name and a [[PageSpec]] of dependencies to add. +* `%IkiWiki::forcerebuild` any pages set as the keys to this hash will be + treated as if they're modified and rebuilt. + +## 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 @@ -95,6 +225,8 @@ 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.