X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/7b07286a6f4a9903d5a346205b8eaaf93dbb9d0d..e853734faaad47887a5142fe414cce5a19cdd202:/doc/plugins/write.mdwn diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn index 4fd9c4369..d2d1a6329 100644 --- a/doc/plugins/write.mdwn +++ b/doc/plugins/write.mdwn @@ -31,20 +31,26 @@ 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. +As a compiler, ikiwiki starts by calling the +[[`refresh`|plugins/write#refresh]] hook. Then it checks the wiki's source to +find new or changed pages. The [[`needsbuild`|plugins/write#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`|plugins/write#scan]] hooks, which collect +metadata about the pages. Then it runs a page rendering pipeline, by calling +in turn these hooks: [[`filter`|plugins/write#filter]], +[[`preprocess`|plugins/write#preprocess]], +[[`linkify`|plugins/write#linkify]], [[`htmlize`|plugins/write#htmlize]], +[[`indexhtml`|plugins/write#indexhtml]], +[[`pagetemplate`|plugins/write#pagetemplate]], +[[`sanitize`|plugins/write#sanitize]], [[`format`|plugins/write#format]]. + +After all necessary pages are built, it calls the +[[`changes`|plugins/write#changes]] hook. Finally, if a page was deleted, the +[[`delete`|plugins/write#delete]] hook is called, and the files that page had +previously produced are removed. ### cgi @@ -53,33 +59,39 @@ 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. +* Ikiwiki is run as a cgi. It assigns Alice a session cookie, and, by calling + the [[`auth`|plugins/write#auth]] hooks, sees that she is not yet logged in. +* The [[`sessioncgi`|plugins/write#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`|plugins/write#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`|plugins/write#formbuilder]] + 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. +* The [[openid]] plugin's [[`formbuilder`|plugins/write#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`|plugins/write#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. +* Now all the [[`canedit`|plugins/write#canedit]] hooks are happy. The + [[editpage]] plugin calls + [[`formbuilder_setup`|plugins/write#formbuilder]] 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. +* The [[editpage]] plugin's [[`formbuilder`|plugins/write#formbuilder]] hook + sees that the Save button was pressed, and calls the + [[`checkcontent`|plugins/write#checkcontent]] and + [[`editcontent`|plugins/write#editcontent]] hooks. Then it saves the page + to disk, and branches into the compiler part of ikiwiki to refresh the wiki. ## Types of plugins @@ -165,7 +177,7 @@ is populated at this point, but other state has not yet been loaded. The function is passed no values. It's ok for the function to call `error()` if something isn't configured right. -### refresh +### refresh hook(type => "refresh", id => "foo", call => \&refresh); @@ -173,16 +185,21 @@ This hook is called just before ikiwiki scans the wiki for changed files. It's useful for plugins that need to create or modify a source page. The function is passed no values. -### needsbuild +### needsbuild hook(type => "needsbuild", id => "foo", call => \&needsbuild); -This allows a plugin to manipulate the list of files that need to be -built when the wiki is refreshed. The function is passed a reference to an -array of files that will be rebuilt, and can modify the array, either -adding or removing files from it. +This allows a plugin to observe or even manipulate the list of files that +need to be built when the wiki is refreshed. + +As its first parameter, the function is passed a reference to an array of +files that will be built. It should return an array reference that is a +modified version of its input. It can add or remove files from it. -### scan +The second parameter passed to the function is a reference to an array of +files that have been deleted. + +### scan hook(type => "scan", id => "foo", call => \&scan); @@ -194,15 +211,15 @@ them to `%links`. Present in IkiWiki 2.40 and later. The function is passed named parameters "page" and "content". Its return value is ignored. -### filter +### 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", +Runs on the full raw source of a page, before anything else touches it, and +can make arbitrary changes. The function is passed named parameters "page", "destpage", and "content". It should return the filtered content. -### preprocess +### preprocess Adding a preprocessor [[ikiwiki/directive]] is probably the most common use of a plugin. @@ -245,7 +262,7 @@ 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. -### linkify +### linkify hook(type => "linkify", id => "foo", call => \&linkify); @@ -258,7 +275,7 @@ Plugins that implement linkify must also implement a scan hook, that scans for the links on the page and adds them to `%links` (typically by calling `add_link`). -### htmlize +### htmlize hook(type => "htmlize", id => "ext", call => \&htmlize); @@ -282,22 +299,22 @@ like `Makefile` that have no extension. If `hook` is passed an optional "longname" parameter, this value is used when prompting a user to choose a page type on the edit page form. -### postscan +### indexhtml - hook(type => "postscan", id => "foo", call => \&postscan); + hook(type => "indexhtml", id => "foo", call => \&indexhtml); This hook is called once the page has been converted to html (but before the generated html is put in a template). The most common use is to update search indexes. Added in ikiwiki 2.54. -The function is passed named parameters "page" and "content". Its return -value is ignored. +The function is passed named parameters "page", "destpage", and "content". +Its return value is ignored. -### pagetemplate +### pagetemplate hook(type => "pagetemplate", id => "foo", call => \&pagetemplate); -[[Templates|wikitemplates]] are filled out for many different things in +[[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 the variables available on those templates. The function is passed named parameters. The "page" and @@ -313,13 +330,22 @@ a new custom parameter to the template. hook(type => "templatefile", id => "foo", call => \&templatefile); -This hook allows plugins to change the [[template|wikitemplates]] that is +This hook allows plugins to change the [[template|templates]] that is used for a page in the wiki. The hook is passed a "page" parameter, and -should return the name of the template file to use, or undef if it doesn't -want to change the default ("page.tmpl"). Template files are looked for in -/usr/share/ikiwiki/templates by default. +should return the name of the template file to use (relative to the +template directory), or undef if it doesn't want to change the default +("page.tmpl"). + +### pageactions + + hook(type => "pageactions", id => "foo", call => \&pageactions); + +This hook allows plugins to add arbitrary actions to the action bar on a +page (next to Edit, RecentChanges, etc). The hook is passed a "page" +parameter, and can return a list of html fragments to add to the action +bar. -### sanitize +### sanitize hook(type => "sanitize", id => "foo", call => \&sanitize); @@ -329,7 +355,7 @@ modify the body of a page after it has been fully converted to html. The function is passed named parameters: "page", "destpage", and "content", and should return the sanitized content. -### format +### format hook(type => "format", id => "foo", call => \&format); @@ -342,21 +368,48 @@ when the page is being previewed.) The function is passed named parameters: "page" and "content", and should return the formatted content. -### delete +### build_affected + + hook(type => "build_affected", id => "foo", call => \&build_affected); + +This hook is called after the directly changed pages have been built, +and can cause extra pages to be built. If links and backlinks were provided +by a plugin, this would be where that plugin would rebuild pages whose +backlinks have changed, for instance. The [[trail]] plugin uses this hook +to rebuild pages whose next or previous page has changed. + +The function should currently ignore its parameters. It returns a list with +an even number of items (a hash in list context), where the first item of +each pair is a page name to be rebuilt (if it was not already rebuilt), and +the second is a log message resembling +`building plugins/write because the phase of the moon has changed`. + +### delete hook(type => "delete", id => "foo", call => \&delete); -Each time a page or pages is removed from the wiki, the referenced function +After 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 +### rendered - hook(type => "change", id => "foo", call => \&render); + hook(type => "rendered", id => "foo", call => \&rendered); -Each time ikiwiki renders a change or addition (but not deletion) to the +After 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. +(This hook used to be called "change", but that was not accurate. +For now, plugins using the old hook name will still work.) + +### changes + + hook(type => "changes", id => "foo", call => \&changes); + +After ikiwiki renders changes to the wiki, the referenced function is +called, and passed the names of the source files that were added, modified, +or deleted. + ### cgi hook(type => "cgi", id => "foo", call => \&cgi); @@ -369,7 +422,7 @@ parameters, and if it will handle this CGI request, output a page Note that cgi hooks are called as early as possible, before any ikiwiki state is loaded, and with no session information. -### auth +### auth hook(type => "auth", id => "foo", call => \&auth); @@ -382,7 +435,7 @@ object's "name" parameter to the authenticated user's name. Note that if the name is set to the name of a user who is not registered, a basic registration of the user will be automatically performed. -### sessioncgi +### sessioncgi hook(type => "sessioncgi", id => "foo", call => \&sessioncgi); @@ -391,7 +444,7 @@ is only run once a session object is available. It is passed both a CGI object and a session object. To check if the user is in fact signed in, you can check if the session object has a "name" parameter set. -### canedit +### canedit hook(type => "canedit", id => "foo", call => \&canedit); @@ -431,7 +484,7 @@ bypass it). It works exactly like the `canedit` hook, but is passed the named parameters `cgi` (a CGI object), `session` (a session object), `src`, `srcfile`, `dest` and `destfile`. -### checkcontent +### checkcontent hook(type => "checkcontent", id => "foo", call => \&checkcontent); @@ -452,7 +505,7 @@ should return a message stating what the problem is, or a function that can be run to perform whatever action is necessary to allow the user to post the content. -### editcontent +### editcontent hook(type => "editcontent", id => "foo", call => \&editcontent); @@ -463,7 +516,7 @@ user, the page name, a `CGI` object, and the user's `CGI::Session`. It can modify the content as desired, and should return the content. -### formbuilder +### formbuilder hook(type => "formbuilder_setup", id => "foo", call => \&formbuilder_setup); hook(type => "formbuilder", id => "foo", call => \&formbuilder); @@ -536,7 +589,7 @@ 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, @@ -566,6 +619,7 @@ describes the plugin as a whole. For example: * `description` is a short description of the option. * `link` is a link to further information about the option. This can either be a [[ikiwiki/WikiLink]], or an url. +* `htmldescription` is displayed instead of the description by websetup. * `advanced` can be set to true if the option is more suitable for advanced users. * `safe` should be false if the option should not be displayed in unsafe @@ -579,14 +633,24 @@ describes the plugin as a whole. For example: 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. + same as the tags used for [[plugins]] on this wiki. ### genwrapper hook(type => "genwrapper", id => "foo", call => \&genwrapper); This hook is used to inject C code (which it returns) into the `main` -function of the ikiwiki wrapper when it is being generated. +function of the ikiwiki wrapper when it is being generated. + +The code runs before anything else -- in particular it runs before +the suid wrapper has sanitized its environment. + +### disable + + hook(type => "disable", id => "foo", call => \&disable); + +This hook is only run when a previously enabled plugin gets disabled +during ikiwiki setup. Plugins can use this to perform cleanups. ## Exported variables @@ -620,7 +684,7 @@ wiki updates. 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 -`$wikistate{$id}{$key}=$value, where `$value` is anything Storable can +`$wikistate{$id}{$key}=$value`, where `$value` is anything Storable can 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. @@ -633,6 +697,22 @@ 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: + + $typedlinks{"foo"} = { + tag => { short_word => 1, metasyntactic_variable => 1 }, + next_page => { bar => 1 }, + }; + +Ordinary [[WikiLinks|ikiwiki/WikiLink]] appear in `%links`, but not in +`%typedlinks`. + ### `%pagesources` The `%pagesources` has can be used to look up the source filename @@ -685,10 +765,31 @@ the entire wiki build and make the wiki unusable. ### `template($;@)` -Creates and returns a [[!cpan HTML::Template]] object. The first parameter -is the name of the file in the template directory. The optional remaining +Creates and returns a [[!cpan HTML::Template]] object. (In a list context, +returns the parameters needed to construct the obhect.) + +The first parameter is the name of the template file. The optional remaining parameters are passed to `HTML::Template->new`. +Normally, the template file is first looked for in the templates/ subdirectory +of the srcdir. Failing that, it is looked for in the templatedir. + +Wiki pages can be used as templates. This should be done only for templates +which it is safe to let wiki users edit. Enable it by passing a filename +with no ".tmpl" extension. Template pages are normally looked for in +the templates/ directory. If the page name starts with "/", a page +elsewhere in the wiki can be used. + +If the template is not found, or contains a syntax error, an error is thrown. + +### `template_depends($$;@)` + +Use this instead of `template()` if the content of a template is being +included into a page. This causes the page to depend on the template, +so it will be updated if the template is modified. + +Like `template()`, except the second parameter is the page. + ### `htmlpage($)` Passed a page name, returns the base name that will be used for a the html @@ -718,7 +819,10 @@ Additional named parameters can be specified: * `filter` is a reference to a function, that is called and passed a page, and returns true if the page should be filtered out of the list. * `sort` specifies a sort order for the list. See - [[ikiwiki/PageSpec/sorting]] for the avilable sort methods. + [[ikiwiki/PageSpec/sorting]] for the avilable sort methods. Note that + if a sort method is specified that depends on the + page content (such as 'meta(foo)'), the deptype needs to be set to + a content dependency. * `reverse` if true, sorts in reverse. * `num` if nonzero, specifies the maximum number of matching pages that will be returned. @@ -736,7 +840,7 @@ By default, dependencies are full content dependencies, meaning that the page will be updated whenever anything matching the PageSpec is modified. This can be overridden by passing a `deptype` value as the third parameter. -#### `pagespec_match($$;@)` +### `pagespec_match($$;@)` Passed a page name, and [[ikiwiki/PageSpec]], returns a true value if the [[ikiwiki/PageSpec]] matches the page. @@ -766,7 +870,7 @@ dependency type from one or more of these keywords: If multiple types are specified, they are combined. -#### `bestlink($$)` +### `bestlink($$)` Given a page and the text of a link on the page, determine which existing page that link best points to. Prefers pages under a @@ -774,7 +878,7 @@ subdirectory with the same name as the source page, failing that goes down the directory tree to the base looking for matching pages, as described in [[ikiwiki/SubPage/LinkingRules]]. -#### `htmllink($$$;@)` +### `htmllink($$$;@)` Many plugins need to generate html links and add them to a page. This is done by using the `htmllink` function. The usual way to call @@ -900,25 +1004,40 @@ search for files. If the directory name is not absolute, ikiwiki will assume it is in the parent directory of the configured underlaydir. -### `displaytime($;$)` +### `displaytime($;$$)` Given a time, formats it for display. The optional second parameter is a strftime format to use to format the time. +If the third parameter is true, this is the publication time of a page. +(Ie, set the html5 pubdate attribute.) + ### `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 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. +Provide a second parameter whenever possible, since this leads to better +behaviour for the [[plugins/po]] plugin and `file:///` URLs. + +If the second parameter is not specified (or `undef`), the URL will be +valid from any page on the wiki, or from the CGI; if possible it'll +be a path starting with `/`, but an absolute URL will be used if +the wiki and the CGI are on different domains. + +If the third parameter is passed and is true, the url will be a fully +absolute url. This is useful when generating an url to publish elsewhere. ### `newpagefile($$)` @@ -935,11 +1054,31 @@ Optionally, a third parameter can be passed, to specify the preferred filename of the page. For example, `targetpage("foo", "rss", "feed")` will yield something like `foo/feed.rss`. -### `add_link($$)` +### `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 @@ -977,16 +1116,20 @@ token, that will be passed into `rcs_commit` when committing. For example, it might return the current revision ID of the file, and use that information later when merging changes. -#### `rcs_commit($$$;$$)` +#### `rcs_commit(@)` + +Passed named parameters: `file`, `message`, `token` (from `rcs_prepedit`), +and `session` (optional). -Passed a file, message, token (from `rcs_prepedit`), user, and ip address. Should try to commit the file. Returns `undef` on *success* and a version of the page with the rcs's conflict markers on failure. -#### `rcs_commit_staged($$$)` +#### `rcs_commit_staged(@)` + +Passed named parameters: `message`, and `session` (optional). -Passed a message, user, and ip address. Should commit all staged changes. -Returns undef on success, and an error message on failure. +Should commit all staged changes. Returns undef on success, and an +error message on failure. Changes can be staged by calls to `rcs_add`, `rcs_remove`, and `rcs_rename`. @@ -1006,9 +1149,7 @@ to version control; the subdir can be added if so. Remove a file. The filename is relative to the root of the srcdir. Note that this should not commit the removal, it should only prepare for it -to be committed when `rcs_commit` (or `rcs_commit_staged`) is called. Note -that the new file may be in a new subdir that is not yet in version -control; the subdir can be added if so. +to be committed when `rcs_commit` (or `rcs_commit_staged`) is called. #### `rcs_rename($$)` @@ -1029,7 +1170,9 @@ The data structure returned for each change is: { rev => # the RCSs id for this commit - user => # name of user who made the change, + user => # user who made the change (may be an openid), + nickname => # short name for user (optional; not an openid), + committype => # either "web" or the name of the rcs, when => # time when the change was made, message => [ @@ -1046,19 +1189,30 @@ The data structure returned for each change is: ], } -#### `rcs_diff($)` +#### `rcs_diff($;$)` + +The first parameter is the rev from `rcs_recentchanges`. +The optional second parameter is how many lines to return (default: all). -The parameter is the rev from `rcs_recentchanges`. Should return a list of lines of the diff (including \n) in list -context, and the whole diff in scalar context. +context, and a string containing the whole diff in scalar context. #### `rcs_getctime($)` This is used to get the page creation time for a file from the RCS, by looking it up in the history. +If the RCS cannot determine a ctime for the file, return 0. + +#### `rcs_getmtime($)` + +This is used to get the page modification time for a file from the RCS, by +looking it up in the history. + It's ok if this is not implemented, and throws an error. +If the RCS cannot determine a mtime for the file, return 0. + #### `rcs_receive()` This is called when ikiwiki is running as a pre-receive hook (or @@ -1068,9 +1222,9 @@ sense to implement for all RCSs. It should examine the incoming changes, and do any sanity checks that are appropriate for the RCS to limit changes to safe file adds, -removes, and changes. If something bad is found, it should exit -nonzero, to abort the push. Otherwise, it should return a list of -files that were changed, in the form: +removes, and changes. If something bad is found, it should die, to abort +the push. Otherwise, it should return a list of files that were changed, +in the form: { file => # name of file that was changed @@ -1083,6 +1237,42 @@ files that were changed, in the form: The list will then be checked to make sure that each change is one that is allowed to be made via the web interface. +#### `rcs_preprevert($)` + +This is called by the revert web interface. It is passed a RCS-specific +change ID, and should determine what the effects would be of reverting +that change, and return the same data structure as `rcs_receive`. + +Like `rcs_receive`, it should do whatever sanity checks are appropriate +for the RCS to limit changes to safe changes, and die if a change would +be unsafe to revert. + +#### `rcs_revert($)` + +This is called by the revert web interface. It is passed a named +parameter rev that is the RCS-specific change ID to revert. + +It should try to revert the specified rev, and leave the reversion staged +so `rcs_commit_staged` will complete it. It should return undef on _success_ +and an error message on failure. + +This hook and `rcs_preprevert` are optional, if not implemented, no revert +web interface will be available. + +### `rcs_find_changes($)` + +Finds changes committed since the passed RCS-specific rev. Returns +a hash of the files changed, a hash of the files deleted, and the +current rev. + +This hook is optional. + +### `rcs_get_current_rev()` + +Gets a RCS-specific rev, which can later be passed to `rcs_find_changes`. + +This hook is optional. + ### PageSpec plugins It's also possible to write plugins that add new functions to @@ -1106,6 +1296,24 @@ 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