`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
change until ikiwiki rebuilds the page for some other reason, like the page
being edited.
-# Registering plugins
+## Registering plugins
+
+All plugins should `use IkiWiki` to import the ikiwiki plugin interface.
-Plugins should, when imported, call IkiWiki::hook to hook into ikiwiki's
+Plugins should, when imported, call `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
+the type of hook being registered -- see below. Note that a plugin can call
+the function more than once to register multiple hooks. All calls to
+`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]]
-
-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.
-
-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
-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 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.
+## Types of hooks
-# Other types of hooks
+In roughly the order they are called.
-Beyond PreProcessorDirectives, Other types of hooks that can be used by
-plugins include:
+### getopt
-## getopt
-
- IkiWiki::hook(type => "getopt", id => "foo", call => \&getopt);
+ 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
+settings in %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
+### checkconfig
- IkiWiki::hook(type => "checkconfig", id => "foo", call => \&checkconfig);
+ 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.
+`error()` if something isn't configured right.
-## filter
+### filter
- IkiWiki::hook(type => "filter", id => "foo", call => \&filter);
+ 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
+### preprocess
+
+Adding a [[PreProcessorDirective]] is probably the most common use of a
+plugin.
- IkiWiki::hook(type => "htmlize", id => "ext", call => \&htmlize);
+ hook(type => "preprocess", id => "foo", call => \&preprocess);
+
+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
+
+ 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.
-## pagetemplate
+The function is passed named parameters: "page" and "content" and should
+return the htmlized content.
- IkiWiki::hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
+### 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.
+ hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
-The most common thing to do is probably to call $template->param() to add
-a new custom parameter to the template. Note that in order to be robust,
-it's a good idea to check whether the template has a variable before trying
-to set it, as setting a variable that's not present is an error.
+[[Templates]] are filled out for many different things in ikiwiki,
+like generating a page, or part of a blog page, or an rss feed, or a cgi.
+This hook allows modifying those templates. The function is passed named
+parameters. The "page" and "destpage" parameters are the same as for a
+preprocess hook. The "template" parameter is a `HTML::Template` object that
+is the template that will be used to generate the page. The function can
+manipulate that template object.
- if ($template->query(name => 'foo')) {
- $template->param("foo" => "bar");
- }
+The most common thing to do is probably to call $template->param() to add
+a new custom parameter to the template.
-## sanitize
+### sanitize
- IkiWiki::hook(type => "sanitize", id => "foo", call => \&sanitize);
+ 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.
+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.
-## delete
+### format
- IkiWiki::hook(type => "delete", id => "foo", call => \&delete);
+ 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
+
+ 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
+### change
- IkiWiki::hook(type => "change", id => "foo", call => \&render);
+ 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
+### cgi
- IkiWiki::hook(type => "cgi", id => "foo", call => \&cgi);
+ 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.
-## savestate
+### savestate
- IkiWiki::hook(type => "savestate", id => "foo", call => \&savestate);
+ hook(type => "savestate", id => "foo", call => \&savestate);
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.
-# Wiki configuration
+## Plugin interface
+
+To import the ikiwiki plugin interface:
-A plugin can access the wiki's configuration via the `%IkiWiki::config`
+ use IkiWiki '1.00';
+
+This will import several variables and functions into your plugin's
+namespace. These variables and functions are the ones most plugins need,
+and a special effort will be made to avoid changing them in incompatible
+ways, and to document any changes that have to be made in the future.
+
+Note that IkiWiki also provides other variables functions that are not
+exported by default. No guarantee is made about these in the future, so if
+it's not exported, the wise choice is to not use it.
+
+### %config
+
+A plugin can access the wiki's configuration via the `%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
+### Other variables
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 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::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 [[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 [[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.
-
-# A note on generating html links
+* `%links` lists the names of each page that a page links to, in an array
+ reference.
+* `%renderedfiles` lists names of the files rendered by a page, in an array
+ reference.
+* `%pagesources` contains the name of the source file for a page.
+
+Also, the %IkiWiki::version variable contains the version number for the
+ikiwiki program.
+
+### Library functions
+
+#### `hook(@)`
+
+Hook into ikiwiki's processing. See the discussion of hooks above.
+
+Note that in addition to the named parameters described above, a parameter
+named no_override is supported, If it's set to a true value, then this hook
+will not override any existing hook with the same id. This is useful if
+the id can be controled by the user.
+
+#### `debug($)`
+
+Logs a debugging message. These are supressed unless verbose mode is turned
+on.
+
+#### `error($)`
+
+Aborts with an error message.
+
+Note that while any plugin can use this for a fatal error, plugins should
+try to avoid dying on bad input, as that will halt the entire wiki build
+and make the wiki unusable. So for example, if a [[PreProcessorDirective]]
+is passed bad parameters, it's better to return an error message, which can
+appear on the wiki page, rather than calling error().
+
+#### `template($;@)`
+
+Creates and returns a HTML::Template object. The first parameter is the
+name of the file in the template directory. The optional remaining
+parameters are passed to HTML::Template->new.
+
+#### `htmlpage($)`
+
+Passed a page name, returns the base name that will be used for a the html
+page created from it. (Ie, it appends ".html".)
+
+#### `add_depends($$)`
+
+Makes the specified page depend on the specified [[PageSpec]].
+
+#### `pagespec_match($$)`
+
+Passed a page name, and a [[PageSpec]], returns true if the [[PageSpec]]
+matches the page.
+
+#### `bestlink($$)`
+
+Given a page and the text of a link on the page, determine which
+existing page that link best points to. Prefers pages under a
+subdirectory with the same name as the source page, failing that
+goes down the directory tree to the base looking for matching
+pages, as described in [[SubPage/LinkingRules]].
+
+#### `htmllink($$$;$$$)`
Many plugins need to generate html links and add them to a page. This is
-done by using the `IkiWiki::htmllink` function. The usual way to call
-htmlllink is:
+done by using the `htmllink` function. The usual way to call
+`htmlllink` is:
htmllink($page, $page, $link)
-Why is $page repeated? Because if a page is inlined inside another, and a
+Why is `$page` repeated? Because if a page is inlined inside another, and a
link is placed on it, the right way to make that link is actually:
htmllink($page, $destpage, $link)
-Here $destpage is the inlining page. A destpage parameter is passed to some
-of the hook functions above; the ones that are not passed it are not used
+Here `$destpage` is the inlining page. A `destpage` parameter is passed to
+some of the hook functions above; the ones that are not passed it are not used
during inlining and don't need to worry about this issue.
-# RCS plugins
+The remaining three optional parameters to `htmllink` are:
+
+1. noimageinline - set to true to avoid turning links into inline html images
+1. forcesubpage - set to force a link to a subpage
+1. linktext - set to force the link text to something
+
+#### `readfile($;$)`
+
+Given a filename, reads and returns the entire file.
+
+The optional second parameter, if set to a true value, makes the file be read
+in binary mode.
+
+A failure to read the file will result in it dying with an error.
+
+#### `writefile($$$;$)`
+
+Given a filename, a directory to put it in, and the file's content,
+writes a file.
+
+The optional second parameter, if set to a true value, makes the file be
+written in binary mode.
+
+A failure to write the file will result in it dying with an error.
+
+If the destination directory doesn't exist, it will first be created.
+
+### `will_render($$)`
+
+Given a page name and a destination file name (not including the base
+destination directory), register that the page will result in that file
+being rendered. It's important to call this before writing to any file in
+the destination directory.
+
+#### `pagetype($)`
+
+Given the name of a source file, returns the type of page it is, if it's
+a type that ikiwiki knowns how to htmlize. Otherwise, returns undef.
+
+#### `pagename($)`
+
+Given the name of a source file, returns the name of the wiki page
+that corresponds to that file.
+
+#### `srcfile($)`
+
+Given the name of a source file in the wiki, searches for the file in
+the source directory and the underlay directory, and returns the full
+path to the first file found.
+
+#### `displaytime($)`
+
+Given a time, formats it for display.
+
+## RCS plugins
ikiwiki's support for revision control systems also uses pluggable perl
modules. These are in the `IkiWiki::RCS` namespace, for example