* Add a googlecalendar plugin. A bit special-purpose, but it shows

[git.ikiwiki.info.git] / doc / plugins / write.mdwn

diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index 925717777d93360639ba3a7402dadb5944db95a5..dd0ab451fdc30be5bf71c0fc01237be5b7c21dfe 100644 (file)
--- 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.
 
 `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
 
 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


@@ -15,7 +17,7 @@ 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.
 
 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
 
 Plugins should, when imported, call IkiWiki::hook to hook into ikiwiki's
 processing. The function uses named parameters, and use varies depending on


@@ -26,45 +28,11 @@ 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.
 
 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.
+## Types of hooks

 
 

-        IkiWiki::hook(type => "preprocess", id => "foo", call => \&preprocess);
+In roughly the order they are called.

 
 

-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.
-
-# Other types of hooks
-
-Beyond PreProcessorDirectives, Other types of hooks that can be used by
-plugins include:
-
-## getopt
+### getopt

 
        IkiWiki::hook(type => "getopt", id => "foo", call => \&getopt);
 
 
        IkiWiki::hook(type => "getopt", id => "foo", call => \&getopt);
 


@@ -77,7 +45,7 @@ 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.
 
 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);
 
 
        IkiWiki::hook(type => "checkconfig", id => "foo", call => \&checkconfig);
 


@@ -86,7 +54,7 @@ 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.
 
 function is passed no values. It's ok for the function to call
 IkiWiki::error if something isn't configured right.
 

-## filter
+### filter

 
        IkiWiki::hook(type => "filter", id => "foo", call => \&filter);
 
 
        IkiWiki::hook(type => "filter", id => "foo", call => \&filter);
 


@@ -94,7 +62,32 @@ 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.
 
 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 => "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

 
        IkiWiki::hook(type => "htmlize", id => "ext", call => \&htmlize);
 
 
        IkiWiki::hook(type => "htmlize", id => "ext", call => \&htmlize);
 


@@ -103,7 +96,10 @@ 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.
 
 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.
+
+### pagetemplate

 
        IkiWiki::hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
 
 
        IkiWiki::hook(type => "pagetemplate", id => "foo", call => \&pagetemplate);
 


@@ -116,31 +112,37 @@ 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
 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.
+a new custom parameter to the template.

 
 

-       if ($template->query(name => 'foo')) {
-               $template->param("foo" => "bar");
-       }
-
-## sanitize
+### sanitize

 
        IkiWiki::hook(type => "sanitize", id => "foo", call => \&sanitize);
 
 Use this to implement html sanitization or anything else that needs to
 
        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.
+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.

 
 

-## delete
+The function is passed named parameters: "page" and "content", and 
+should return the formatted content.
+
+### delete

 
        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.
 
 
        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
+### change

 
        IkiWiki::hook(type => "change", id => "foo", call => \&render);
 
 
        IkiWiki::hook(type => "change", id => "foo", call => \&render);
 


@@ -148,7 +150,7 @@ 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.
 
 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);
 
 
        IkiWiki::hook(type => "cgi", id => "foo", call => \&cgi);
 


@@ -157,7 +159,7 @@ 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.
 
 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);
 
 
        IkiWiki::hook(type => "savestate", id => "foo", call => \&savestate);
 


@@ -165,13 +167,20 @@ 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.
 
 the state is saved. The function can save other state, modify values before
 they're saved, etc.
 

-# Wiki configuration
+## 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.
+
+## 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.
 
 
 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:
 
 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:


@@ -183,17 +192,17 @@ 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::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
   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.
 
 * `%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
+## 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
 
 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


@@ -210,7 +219,7 @@ 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.
 
 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
+## RCS plugins

 
 ikiwiki's support for revision control systems also uses pluggable perl
 modules. These are in the `IkiWiki::RCS` namespace, for example
 
 ikiwiki's support for revision control systems also uses pluggable perl
 modules. These are in the `IkiWiki::RCS` namespace, for example