X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/b1c47b4065b245ccf46b99292d7de61800468237..9c8761ba49b06a76a923eb91735f842f419d2916:/doc/plugins/write.mdwn?ds=inline diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn index 17c54ffc7..404c3b44f 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, @@ -528,13 +592,13 @@ function of the ikiwiki wrapper when it is being generated. 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 @@ -561,28 +625,52 @@ 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"]; -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()`. +### `%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 }, + }; + +Ordinary [[WikiLinks|ikiwiki/WikiLink]] appear in `%links`, but not in +`%typedlinks`. -### %pagesources +### `%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"; + ## 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. @@ -646,7 +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. @@ -664,7 +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. @@ -694,7 +785,7 @@ 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 +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 @@ -839,6 +930,10 @@ time. This is the standard gettext function, although slightly optimised. +### `ngettext` + +This is the standard ngettext function, although slightly optimised. + ### `urlto($$;$)` Construct a relative url to the first parameter from the page named by the @@ -863,11 +958,31 @@ Optionally, a third parameter can be passed, to specify the preferred filename of the page. For example, `targetpage("foo", "rss", "feed")` will yield something like `foo/feed.rss`. -### `add_link($$)` +### `add_link($$;$)` This adds a link to `%links`, ensuring that duplicate links are not added. Pass it the page that contains the link, and the link text. +An optional third parameter sets the link type. If not specified, +it is an ordinary [[ikiwiki/WikiLink]]. + +### `add_autofile($$$)` + +Sometimes you may want to add a file to the `srcdir` as a result of content +of other pages. For example, [[plugins/tag]] pages can be automatically +created as needed. This function can be used to do that. + +The three parameters are the filename to create (relative to the `srcdir`), +the name of the plugin, and a callback function. The callback will be +called if it is appropriate to automatically add the file, and should then +take care of creating it, and doing anything else it needs to (such as +checking it into revision control). Note that the callback may not always +be called. For example, if an automatically added file is deleted by the +user, ikiwiki will avoid re-adding it again. + +This function needs to be called during the scan hook, or earlier in the +build process, in order to add the file early enough for it to be built. + ## Miscellaneous ### Internal use pages @@ -987,6 +1102,17 @@ 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($)` + +This is used to get the page modification time for a file from the RCS, by +looking it up in the history. + +It's ok if this is not implemented, and throws an error. + +If the RCS cannot determine a mtime for the file, return 0. + #### `rcs_receive()` This is called when ikiwiki is running as a pre-receive hook (or @@ -1034,6 +1160,24 @@ For example, "backlink(foo)" is influenced by the contents of page foo; they match; "created_before(foo)" is influenced by the metadata of foo; while "glob(*)" is not influenced by the contents of any page. +### Sorting plugins + +Similarly, it's possible to write plugins that add new functions as +[[ikiwiki/pagespec/sorting]] methods. To achieve this, add a function to +the IkiWiki::SortSpec package named `cmp_foo`, which will be used when sorting +by `foo` or `foo(...)` is requested. + +The names of pages to be compared are in the global variables `$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