X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/5d566d8b32e7ec260df996366b471631d6a3b47c..c944bffe3dbad0746880a0cd573808f04505ebdd:/doc/plugins/write.mdwn?ds=sidebyside diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn index 712dda8bf..96a2aa16d 100644 --- a/doc/plugins/write.mdwn +++ b/doc/plugins/write.mdwn @@ -3,8 +3,84 @@ written to extend ikiwiki in many ways. Despite the length of this page, it's not really hard. This page is a complete reference to everything a plugin might want to do. There is also a quick [[tutorial]]. +[[!template id="note" text=""" +Ikiwiki is a compiler + +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 +are loaded. A plugin that inserts the current time into a page, for +example, will insert the build time. + +Also, as a compiler, ikiwiki avoids rebuilding pages unless they have +changed, so a plugin that prints some 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. + +The [[tutorial]] has some other examples of ways that ikiwiki being a +compiler may trip up the unwary. +"""]] + [[!toc levels=2]] +## Highlevel view of ikiwiki + +Ikiwiki mostly has two modes of operation. It can either be running +as a compiler, building or updating a wiki; or as a cgi program, providing +user interface for editing pages, etc. Almost everything ikiwiki does +is accomplished by calling various hooks provided by plugins. + +### compiler + +As a compiler, ikiwiki starts by calling the `refresh` hook. Then it checks +the wiki's source to find new or changed pages. The `needsbuild` hook is +then called to allow manipulation of the list of pages that need to be +built. + +Now that it knows what pages it needs to build, ikiwiki runs two +compile passes. First, it runs `scan` hooks, which collect metadata about +the pages. Then it runs a page rendering pipeline, by calling in turn these +hooks: `filter`, `preprocess`, `linkify`, `htmlize`, `postscan`, +`pagetemplate`, `sanitize`, `format`. + +After all necessary pages are built, it calls the `change` hook. Finally, +if a page is was deleted, the `delete` hook is called, and the files that +page had previously produced are removed. + +### cgi + +The flow between hooks when ikiwiki is run as a cgi is best illustrated by +an example. + +Alice browses to a page and clicks Edit. + +* Ikiwiki is run as a cgi. It assigns Alice a session cookie, and, + by calling the `auth` hooks, sees that she is not yet logged in. +* The `sessioncgi` hooks are then called, and one of them, + from the [[editpage]] plugin, notices that the cgi has been told "do=edit". +* The [[editpage]] plugin calls the `canedit` hook to check if this + page edit is allowed. The [[signinedit]] plugin has a hook that says not: + Alice is not signed in. +* The [[signinedit]] plugin then launches the signin process. A signin + page is built by calling the `formbuilder_setup` hook. + +Alice signs in with her openid. + +* The [[openid]] plugin's `formbuilder` hook sees that an openid was + entered in the signin form, and redirects to Alice's openid provider. +* Alice's openid provider calls back to ikiwiki. The [[openid]] plugin + has an `auth` hook that finishes the openid signin process. +* Signin complete, ikiwiki returns to what Alice was doing before; editing + a page. +* Now all the `canedit` hooks are happy. The [[editpage]] plugin calls + `formbuilder_setup` to display the page editing form. + +Alice saves her change to the page. + +* The [[editpage]] plugin's `formbuilder` hook sees that the Save button + was pressed, and calls the `checkcontent` and `editcontent` hooks. + Then it saves the page to disk, and branches into the compiler part + of ikiwiki to refresh the wiki. + ## Types of plugins Most ikiwiki [[plugins]] are written in perl, like ikiwiki. This gives the @@ -31,18 +107,6 @@ they're the same as far as how they hook into ikiwiki. This document will explain how to write both sorts of plugins, albeit with an emphasis on perl plugins. -## Remember: Ikiwiki is a compiler - -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 -are loaded. A plugin that inserts the current time into a page, for -example, will insert the build time. Also, as a compiler, ikiwiki avoids -rebuilding pages unless they have changed, so a plugin that prints some -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. The [[tutorial]] has some other examples of ways that ikiwiki -being a compiler may trip up the unwary. - ## Plugin interface To import the ikiwiki plugin interface: @@ -472,7 +536,7 @@ The data returned is a list of `%config` options, followed by a hash describing the option. There can also be an item named "plugin", which describes the plugin as a whole. For example: - return + return plugin => { description => "description of this plugin", safe => 1, @@ -524,17 +588,17 @@ describes the plugin as a whole. For example: This hook is used to inject C code (which it returns) into the `main` function of the ikiwiki wrapper when it is being generated. -### Exported variables +## Exported variables Several variables are exported to your plugin when you `use IkiWiki;` -#### %config +### `%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 your ikiwiki setup file, which sets the hash content to configure the wiki. -#### %pagestate +### `%pagestate` The `%pagestate` hash can be used by plugins to save state that they will need next time ikiwiki is run. The hash holds per-page state, so to set a value, @@ -552,7 +616,7 @@ When pages are deleted, ikiwiki automatically deletes their pagestate too. Note that page state does not persist across wiki rebuilds, only across wiki updates. -#### %wikistate +### `%wikistate` The `%wikistate` hash can be used by a plugin to store persistant state that is not bound to any one page. To set a value, use @@ -561,29 +625,37 @@ serialize, `$key` is any string you like, and `$id` must be the same as the "id" parameter passed to `hook()` when registering the plugin, so that the state can be dropped if the plugin is no longer used. -#### %links +### `%links` The `%links` hash can be used to look up the names of each page that a page links to. The name of the page is the key; the value is an array reference. Do not modify this hash directly; call `add_link()`. -#### %destsources + $links{"foo"} = ["bar", "baz"]; + +### `%pagesources` + +The `%pagesources` has can be used to look up the source filename +of a page. So the key is the page name, and the value is the source +filename. Do not modify this hash. + + $pagesources{"foo"} = "foo.mdwn"; + +### `%destsources` The `%destsources` hash records the name of the source file used to create each destination file. The key is the output filename (ie, "foo/index.html"), and the value is the source filename that it was built from (eg, "foo.mdwn"). Note that a single source file may create multiple destination files. Do not modify this hash directly; call `will_render()`. + + $destsources{"foo/index.html"} = "foo.mdwn"; -#### %pagesources - -The `%pagesources` has can be used to look up the source filename -of a page. So the key is the page name, and the value is the source -filename. Do not modify this hash. +## Library functions -### Library functions +Several functions are exported to your plugin when you `use IkiWiki;` -#### `hook(@)` +### `hook(@)` Hook into ikiwiki's processing. See the discussion of hooks above. @@ -592,12 +664,12 @@ named `no_override` is supported, If it's set to a true value, then this hook will not override any existing hook with the same id. This is useful if the id can be controled by the user. -#### `debug($)` +### `debug($)` Logs a debugging message. These are supressed unless verbose mode is turned on. -#### `error($;$)` +### `error($;$)` Aborts with an error message. If the second parameter is passed, it is a function that is called after the error message is printed, to do any final @@ -611,13 +683,13 @@ In other hooks, error() is a fatal error, so use with care. Try to avoid dying on bad input when building a page, as that will halt the entire wiki build and make the wiki unusable. -#### `template($;@)` +### `template($;@)` Creates and returns a [[!cpan HTML::Template]] object. The first parameter is the name of the file in the template directory. The optional remaining parameters are passed to `HTML::Template->new`. -#### `htmlpage($)` +### `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".) @@ -625,7 +697,7 @@ page created from it. (Ie, it appends ".html".) Use this when constructing the filename of a html file. Use `urlto` when generating a link to a page. -#### `pagespec_match_list($$;@)` +### `pagespec_match_list($$;@)` Passed a page name, and [[ikiwiki/PageSpec]], returns a list of pages in the wiki that match the [[ikiwiki/PageSpec]]. @@ -656,7 +728,7 @@ Additional named parameters can be specified: Any other named parameters are passed on to `pagespec_match`, to further limit the match. -#### `add_depends($$;$)` +### `add_depends($$;$)` Makes the specified page depend on the specified [[ikiwiki/PageSpec]]. @@ -664,7 +736,7 @@ By default, dependencies are full content dependencies, meaning that the page will be updated whenever anything matching the PageSpec is modified. This can be overridden by passing a `deptype` value as the third parameter. -#### `pagespec_match($$;@)` +### `pagespec_match($$;@)` Passed a page name, and [[ikiwiki/PageSpec]], returns a true value if the [[ikiwiki/PageSpec]] matches the page. @@ -678,7 +750,7 @@ The most often used is "location", which specifies the location the PageSpec should match against. If not passed, relative PageSpecs will match relative to the top of the wiki. -#### `deptype(@)` +### `deptype(@)` Use this function to generate ikiwiki's internal representation of a dependency type from one or more of these keywords: @@ -694,7 +766,7 @@ dependency type from one or more of these keywords: If multiple types are specified, they are combined. -#### `bestlink($$)` +### `bestlink($$)` 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 @@ -702,7 +774,7 @@ 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 [[ikiwiki/SubPage/LinkingRules]]. -#### `htmllink($$$;@)` +### `htmllink($$$;@)` Many plugins need to generate html links and add them to a page. This is done by using the `htmllink` function. The usual way to call @@ -730,7 +802,7 @@ control some options. These are: * class - set to add a css class to the link * title - set to add a title attribute to the link -#### `readfile($;$)` +### `readfile($;$)` Given a filename, reads and returns the entire file. @@ -739,7 +811,7 @@ in binary mode. A failure to read the file will result in it dying with an error. -#### `writefile($$$;$$)` +### `writefile($$$;$$)` Given a filename, a directory to put it in, and the file's content, writes a file. @@ -767,7 +839,7 @@ generally the directory parameter is a trusted toplevel directory like the srcdir or destdir, and any subdirectories of this are included in the filename parameter. -#### `will_render($$)` +### `will_render($$)` Given a page name and a destination file name (not including the base destination directory), register that the page will result in that file @@ -783,34 +855,34 @@ Ikiwiki uses this information to automatically clean up rendered files when the page that rendered them goes away or is changed to no longer render them. will_render also does a few important security checks. -#### `pagetype($)` +### `pagetype($)` 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($)` +### `pagename($)` Given the name of a source file, returns the name of the wiki page that corresponds to that file. -#### `pagetitle($)` +### `pagetitle($)` Give the name of a wiki page, returns a version suitable to be displayed as the page's title. This is accomplished by de-escaping escaped characters in the page name. "_" is replaced with a space, and '__NN__' is replaced by the UTF character with code NN. -#### `titlepage($)` +### `titlepage($)` This performs the inverse of `pagetitle`, ie, it converts a page title into a wiki page name. -#### `linkpage($)` +### `linkpage($)` This converts text that could have been entered by the user as a [[ikiwiki/WikiLink]] into a wiki page name. -#### `srcfile($;$)` +### `srcfile($;$)` Given the name of a source file in the wiki, searches for the file in the source directory and the underlay directories (most recently added @@ -820,7 +892,7 @@ Normally srcfile will fail with an error message if the source file cannot be found. The second parameter can be set to a true value to make it return undef instead. -#### `add_underlay($)` +### `add_underlay($)` Adds a directory to the set of underlay directories that ikiwiki will search for files. @@ -828,18 +900,22 @@ search for files. If the directory name is not absolute, ikiwiki will assume it is in the parent directory of the configured underlaydir. -#### `displaytime($;$)` +### `displaytime($;$)` Given a time, formats it for display. The optional second parameter is a strftime format to use to format the time. -#### `gettext` +### `gettext` This is the standard gettext function, although slightly optimised. -#### `urlto($$;$)` +### `ngettext` + +This is the standard ngettext function, although slightly optimised. + +### `urlto($$;$)` Construct a relative url to the first parameter from the page named by the second. The first parameter can be either a page name, or some other @@ -848,13 +924,13 @@ destination file, as registered by `will_render`. If the third parameter is passed and is true, an absolute url will be constructed instead of the default relative url. -#### `newpagefile($$)` +### `newpagefile($$)` This can be called when creating a new page, to determine what filename to save the page to. It's passed a page name, and its type, and returns the name of the file to create, relative to the srcdir. -#### `targetpage($$;$)` +### `targetpage($$;$)` Passed a page and an extension, returns the filename that page will be rendered to. @@ -863,7 +939,7 @@ Optionally, a third parameter can be passed, to specify the preferred filename of the page. For example, `targetpage("foo", "rss", "feed")` will yield something like `foo/feed.rss`. -#### `add_link($$)` +### `add_link($$)` This adds a link to `%links`, ensuring that duplicate links are not added. Pass it the page that contains the link, and the link text.