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diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn index 082f0e38f..0bf6fcf48 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 @@ -31,16 +107,20 @@ 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. -## Considerations +## Plugin interface -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. +To import the ikiwiki plugin interface: + + use IkiWiki '3.00'; + +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 and 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. ## Registering plugins @@ -456,7 +536,13 @@ 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, + rebuild => 1, + section => "misc", + }, option_foo => { type => "boolean", description => "enable foo?", @@ -471,11 +557,6 @@ describes the plugin as a whole. For example: safe => 1, rebuild => 0, }, - plugin => { - description => "description of this plugin", - safe => 1, - rebuild => 1, - }, * `type` can be "boolean", "string", "integer", "pagespec", or "internal" (used for values that are not user-visible). The type is @@ -496,6 +577,9 @@ describes the plugin as a whole. For example: the plugin) will require a wiki rebuild, false if no rebuild is needed, and undef if a rebuild could be needed in some circumstances, but is not strictly required. +* `section` can optionally specify which section in the config file + the plugin fits in. The convention is to name the sections the + same as the tags used for [[plugins|plugin]] on this wiki. ### genwrapper @@ -504,28 +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. -## Plugin interface - -To import the ikiwiki plugin interface: - - use IkiWiki '3.00'; - -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. +## Exported variables -Note that IkiWiki also provides other variables and 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. +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, @@ -543,7 +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 @@ -552,23 +625,53 @@ 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. -### Other variables +### `%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()`. + + $links{"foo"} = ["bar", "baz"]; + +### `%typedlinks` + +The `%typedlinks` hash records links of specific types. Do not modify this +hash directly; call `add_link()`. The keys are page names, and the values +are hash references. In each page's hash reference, the keys are link types +defined by plugins, and the values are hash references with link targets +as keys, and 1 as a dummy value, something like this: + + $typedlinks{"foo"} = { + tag => { short_word => 1, metasyntactic_variable => 1 }, + next_page => { bar => 1 }, + }; -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: +Ordinary [[WikiLinks|ikiwiki/WikiLink]] appear in `%links`, but not in +`%typedlinks`. -* `%links` lists the names of each page that a page links to, in an array - reference. -* `%destsources` contains the name of the source file used to create each - destination file. -* `%pagesources` contains the name of the source file for each page. +### `%pagesources` -Also, the `%IkiWiki::version` variable contains the version number for the -ikiwiki program. +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 + $pagesources{"foo"} = "foo.mdwn"; -#### `hook(@)` +### `%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()`. + + $destsources{"foo/index.html"} = "foo.mdwn"; + +## Library functions + +Several functions are exported to your plugin when you `use IkiWiki;` + +### `hook(@)` Hook into ikiwiki's processing. See the discussion of hooks above. @@ -577,12 +680,12 @@ named `no_override` is supported, If it's set to a true value, then this hook will not override any existing hook with the same id. This is useful if the id can be controled by the user. -#### `debug($)` +### `debug($)` Logs a debugging message. These are supressed unless verbose mode is turned on. -#### `error($;$)` +### `error($;$)` Aborts with an error message. If the second parameter is passed, it is a function that is called after the error message is printed, to do any final @@ -596,13 +699,13 @@ In other hooks, error() is a fatal error, so use with care. Try to avoid dying on bad input when building a page, as that will halt the entire wiki build and make the wiki unusable. -#### `template($;@)` +### `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".) @@ -610,23 +713,7 @@ 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. -### `deptype(@)` - -Use this function to generate ikiwiki's internal representation of a -dependency type from one or more of these keywords: - -* `content` is the default. Any change to the content - of a page triggers the dependency. -* `presence` is only triggered by a change to the presence - of a page. -* `links` is only triggered by a change to the links of a page. - This includes when a link is added, removed, or changes what - it points to due to other changes. It does not include the - addition or removal of a duplicate link. - -If multiple types are specified, they are combined. - -#### `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]]. @@ -647,7 +734,10 @@ Additional named parameters can be specified: * `filter` is a reference to a function, that is called and passed a page, and returns true if the page should be filtered out of the list. * `sort` specifies a sort order for the list. See - [[ikiwiki/PageSpec/sorting]] for the avilable sort methods. + [[ikiwiki/PageSpec/sorting]] for the avilable sort methods. Note that + if a sort method is specified that depends on the + page content (such as 'meta(foo)'), the deptype needs to be set to + a content dependency. * `reverse` if true, sorts in reverse. * `num` if nonzero, specifies the maximum number of matching pages that will be returned. @@ -657,7 +747,7 @@ 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]]. @@ -665,7 +755,7 @@ 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. @@ -679,7 +769,23 @@ 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. -#### `bestlink($$)` +### `deptype(@)` + +Use this function to generate ikiwiki's internal representation of a +dependency type from one or more of these keywords: + +* `content` is the default. Any change to the content + of a page triggers the dependency. +* `presence` is only triggered by a change to the presence + of a page. +* `links` is only triggered by a change to the links of a page. + This includes when a link is added, removed, or changes what + it points to due to other changes. It does not include the + addition or removal of a duplicate link. + +If multiple types are specified, they are combined. + +### `bestlink($$)` 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 @@ -687,7 +793,7 @@ 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 @@ -715,7 +821,7 @@ 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. @@ -724,7 +830,7 @@ 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. @@ -752,7 +858,7 @@ 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 @@ -768,34 +874,34 @@ 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 @@ -805,7 +911,7 @@ 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. @@ -813,18 +919,22 @@ 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 @@ -833,13 +943,13 @@ 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. @@ -848,11 +958,14 @@ 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($$)` +### `add_link($$;$)` This adds a link to `%links`, ensuring that duplicate links are not added. Pass it the page that contains the link, and the link text. +An optional third parameter sets the link type. If not specified, +it is an ordinary [[ikiwiki/WikiLink]]. + ## Miscellaneous ### Internal use pages @@ -972,6 +1085,17 @@ it up in the history. It's ok if this is not implemented, and throws an error. +If the RCS cannot determine a ctime for the file, return 0. + +#### `rcs_getmtime($)` + +This is used to get the page modification time for a file from the RCS, by +looking it up in the history. + +It's ok if this is not implemented, and throws an error. + +If the RCS cannot determine a mtime for the file, return 0. + #### `rcs_receive()` This is called when ikiwiki is running as a pre-receive hook (or @@ -1019,6 +1143,24 @@ For example, "backlink(foo)" is influenced by the contents of page foo; they match; "created_before(foo)" is influenced by the metadata of foo; while "glob(*)" is not influenced by the contents of any page. +### Sorting plugins + +Similarly, it's possible to write plugins that add new functions as +[[ikiwiki/pagespec/sorting]] methods. To achieve this, add a function to +the IkiWiki::SortSpec package named `cmp_foo`, which will be used when sorting +by `foo` or `foo(...)` is requested. + +The names of pages to be compared are in the global variables `$a` and `$b` +in the IkiWiki::SortSpec package. The function should return the same thing +as Perl's `cmp` and `<=>` operators: negative if `$a` is less than `$b`, +positive if `$a` is greater, or zero if they are considered equal. It may +also raise an error using `error`, for instance if it needs a parameter but +one isn't provided. + +The function will also be passed one or more parameters. The first is +`undef` if invoked as `foo`, or the parameter `"bar"` if invoked as `foo(bar)`; +it may also be passed additional, named parameters. + ### Setup plugins The ikiwiki setup file is loaded using a pluggable mechanism. If you look |