X-Git-Url: http://git.vanrenterghem.biz/git.ikiwiki.info.git/blobdiff_plain/d472e293cd1c8b15e79b7075be1068bba3ec4af1..51d7da8c8785f47417c5d50b55daad78f65155ce:/doc/plugins/write.mdwn?ds=inline

diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index 1aaaf1d1e..7d606eaa9 100644
--- a/doc/plugins/write.mdwn
+++ b/doc/plugins/write.mdwn
@@ -20,6 +20,8 @@ being edited.
 ## Registering plugins
 
 All plugins should `use IkiWiki` to import the ikiwiki plugin interface.
+It's a good idea to include the version number of the plugin interface that
+your plugin expects: `use IkiWiki 2.00`
 
 Plugins should, when imported, call `hook()` to hook into ikiwiki's
 processing. The function uses named parameters, and use varies depending on
@@ -30,12 +32,6 @@ 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.
 
-An optional "scan" parameter, if set to a true value, makes the hook be
-called during the preliminary scan that ikiwiki makes of updated pages,
-before begining to render pages. This parameter should be set to true if
-the hook modifies data in `%links`. Note that doing so will make the hook
-be run twice per page build, so avoid doing it for expensive hooks.
-
 An optional "last" parameter, if set to a true value, makes the hook run
 after all other hooks of its type. Useful if the hook depends on some other
 hook being run first.
@@ -66,21 +62,22 @@ configuration. It's called early in the startup process. The
 function is passed no values. It's ok for the function to call
 `error()` if something isn't configured right.
 
-### filter
+### needsbuild
 
-	hook(type => "filter", id => "foo", call => \&filter);
+	hook(type => "needsbuild", id => "foo", call => \&needsbuild);
 
-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.
+This allows a plugin the 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 pages that will be rebuilt, and can modify the array, either
+adding or removing files from it.
 
-### scan
+### filter
 
-	hook(type => "scan", id => "foo", call => \&scan);
+	hook(type => "filter", id => "foo", call => \&filter);
 
-This is identical to a preprocess hook (see below), except that it is
-called in the initial pass that scans pages for data that will be used in
-later passes. Scan hooks are the only hook that should modify 
+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",
+"destpage", and "content". It should return the filtered content.
 
 ### preprocess
 
@@ -96,9 +93,17 @@ 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 gives 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.
+content is going to (different for inlined pages), and a "preview"
+parameter is set to a true value if the page is being previewed. 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.
+
+An optional "scan" parameter, if set to a true value, makes the hook be
+called during the preliminary scan that ikiwiki makes of updated pages,
+before begining to render pages. This parameter should be set to true if
+the hook modifies data in `%links`. Note that doing so will make the hook
+be run twice per page build, so avoid doing it for expensive hooks.
 
 Note that if the [[htmlscrubber]] is enabled, html in
 [[PreProcessorDirective]] output is sanitised, which may limit what your
@@ -131,7 +136,7 @@ preprocess hook. The "template" parameter is a [[cpan HTML::Template]]
 object that is the template that will be used to generate the page. The
 function can manipulate that template object.
 
-The most common thing to do is probably to call $template->param() to add
+The most common thing to do is probably to call `$template->param()` to add
 a new custom parameter to the template.
 
 ### sanitize
@@ -216,8 +221,8 @@ CGI::FormBuilder]] to generate web forms. These hooks are passed named
 parameters: `cgi`, `session`, and `form`. These are, respectively, the
 `CGI` object, the user's `CGI::Session`, and a `CGI::FormBuilder`.
 
-Each time a form is set up, the formbuilder_setup hook is called.
-Typically the formbuilder_setup hook will check the form's title, and if
+Each time a form is set up, the `formbuilder_setup` hook is called.
+Typically the `formbuilder_setup` hook will check the form's title, and if
 it's a form that it needs to modify, will call various methods to
 add/remove/change fields, tweak the validation code for the fields, etc. It
 will not validate or display the form.
@@ -262,11 +267,11 @@ hash. The best way to understand the contents of the hash is to look at
 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:
 
-* `%links` lists the names of each page that a page links to, in an array
+* `links` lists the names of each page that a page links to, in an array
   reference.
-* `%renderedfiles` lists names of the files rendered by a page, in an array
-  reference.
-* `%pagesources` contains the name of the source file for a page.
+* `%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.
 
 Also, the %IkiWiki::version variable contains the version number for the
 ikiwiki program.
@@ -278,7 +283,7 @@ ikiwiki program.
 Hook into ikiwiki's processing. See the discussion of hooks above.
 
 Note that in addition to the named parameters described above, a parameter
-named no_override is supported, If it's set to a true value, then this hook
+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.
 
@@ -287,9 +292,11 @@ the id can be controled by the user.
 Logs a debugging message. These are supressed unless verbose mode is turned
 on.
 
-#### `error($)`
+#### `error($;$)`
 
-Aborts with an error message.
+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
+cleanup.
 
 Note that while any plugin can use this for a fatal error, plugins should
 try to avoid dying on bad input, as that will halt the entire wiki build
@@ -301,7 +308,7 @@ appear on the wiki page, rather than calling error().
 
 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.
+parameters are passed to `HTML::Template->new`.
 
 #### `htmlpage($)`
 
@@ -312,12 +319,15 @@ page created from it. (Ie, it appends ".html".)
 
 Makes the specified page depend on the specified [[PageSpec]].
 
-#### `pagespec_match($$;$)`
+#### `pagespec_match($$;@)`
+
+Passed a page name, and [[PageSpec]], returns true if the [[PageSpec]]
+matches the page.
 
-Passed a page name, a [[PageSpec]], and the location the [[PageSpec]] should
-be matched against, returns true if the [[PageSpec]] matches the page. (If
-the third parameter is not passed, relative PageSpecs will match relative to
-the top of the wiki.)
+Additional named parameters can be passed, to further limit the match.
+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($$)`
 
@@ -327,7 +337,7 @@ 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 [[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
@@ -344,11 +354,13 @@ 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.
 
-The remaining three optional parameters to `htmllink` are:
+After the three required parameters, named parameters can be used to
+control some options. These are:
 
-1. noimageinline - set to true to avoid turning links into inline html images
-1. forcesubpage  - set to force a link to a subpage
-1. linktext - set to force the link text to something
+* noimageinline - set to true to avoid turning links into inline html images
+* forcesubpage  - set to force a link to a subpage
+* linktext - set to force the link text to something
+* anchor - set to make the link include an anchor
 
 #### `readfile($;$)`
 
@@ -359,14 +371,20 @@ 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. 
 
-The optional second parameter, if set to a true value, makes the file be
+The optional fourth parameter, if set to a true value, makes the file be
 written in binary mode.
 
+The optional fifth parameter can be used to pass a function reference that
+will be called to handle writing to the file. The function will be called
+and passed a file descriptor it should write to, and an error recovery
+function it should call if the writing fails. (You will not normally need to
+use this interface.)
+
 A failure to write the file will result in it dying with an error.
 
 If the destination directory doesn't exist, it will first be created.
@@ -402,14 +420,34 @@ Given a time, formats it for display.
 
 This is the standard gettext function, although slightly optimised.
 
+#### `urlto($$)`
+
+Construct a relative url to the first parameter from the second.
+
+#### `targetpage($$)`
+
+Passed a page and an extension, returns the filename that page will be
+rendered to.
+
 ## RCS plugins
 
 ikiwiki's support for revision control systems also uses pluggable perl
 modules. These are in the `IkiWiki::RCS` namespace, for example
 `IkiWiki::RCS::svn`. 
 
-Each RCS plugin must support all the IkiWiki::rcs\_* functions.
+Each RCS plugin must support all the `IkiWiki::rcs_*` functions.
 See IkiWiki::RCS::Stub for the full list of functions. It's ok if
-rcs\_getctime does nothing except for throwing an error.
+`rcs_getctime` does nothing except for throwing an error.
 
 See [[about_RCS_backends]] for some more info.
+
+## PageSpec plugins
+
+It's also possible to write plugins that add new functions to
+[[PageSpecs|PageSpec]]. Such a plugin should add a function to the
+IkiWiki::PageSpec package, that is named `match_foo`, where "foo()" is
+how it will be accessed in a [[PageSpec]]. The function will be passed
+two parameters: The name of the page being matched, and the thing to match
+against. It may also be passed additional, named parameters. It should return
+a IkiWiki::SuccessReason object if the match succeeds, or an
+IkiWiki::FailReason object if the match fails.