Use this to hook into ikiwiki's cgi script. Each registered cgi hook is
called in turn, and passed a CGI object. The hook should examine the
-parameters, and if it will handle this CGI request, output a page (including the http headers) and
-terminate the program.
+parameters, and if it will handle this CGI request, output a page
+(including the http headers) and terminate the program.
+
+Note that cgi hooks are called as early as possible, before any ikiwiki
+state is loaded, and with no session information.
### auth
Given a page name and a destination file name (not including the base
destination directory), register that the page will result in that file
-being rendered. It's important to call this before writing to any file in
-the destination directory.
+being rendered.
+
+It's important to call this before writing to any file in the destination
+directory, and it's important to call it consistently every time, even if
+the file isn't really written this time -- unless you delete any old
+version of the file. In particular, in preview mode, this should still be
+called even if the file isn't going to be written to during the preview.
Ikiwiki uses this information to automatically clean up rendered files when
the page that rendered them goes away or is changes to no longer render
## Internal use pages
-Sometimes it's useful to put pages in the wiki without having them be
-rendered to individual html files. Such internal use pages are collected
-together to form the RecentChanges page, for example.
+Sometimes it's useful to put pages in the wiki without the overhead of
+having them be rendered to individual html files. Such internal use pages
+are collected together to form the RecentChanges page, for example.
To make an internal use page, register a filename extension that starts
-with "_". Internal use pages cannot be edited with the web interface, are
-not scanned for wikilinks (though wikilinks and preprocessor directives can
-still appear on them, this is rarely a good idea), and are not matched by
-regular PageSpecs glob patterns, but instead only by a special `internal()`
+with "_". Internal use pages cannot be edited with the web interface,
+generally shouldn't contain wikilinks or preprocessor directives (use
+either on them with extreme caution), and are not matched by regular
+PageSpecs glob patterns, but instead only by a special `internal()`
[[ikiwiki/PageSpec]].
## RCS plugins