hook.
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.
+after all other hooks of its type, and an optional "first" parameter makes
+it run first. Useful if the hook depends on some other hook being run first.
## Types of hooks
### canedit
- hook(type => "canedit", id => "foo", call => \&pagelocked);
+ hook(type => "canedit", id => "foo", call => \&canedit);
This hook can be used to implement arbitrary access methods to control when
a page can be edited using the web interface (commits from revision control
since it's sometimes used to test to see which pages in a set of pages a
user can edit.
+### checkcontent
+
+ hook(type => "checkcontent", id => "foo", call => \&checkcontent);
+
+This hook is called to check the content a user has entered on a page,
+before it is saved, and decide if it should be allowed.
+
+It is passed named parameters: `content`, `page`, `cgi`, and `session`. If
+the content the user has entered is a comment, it may also be passed some
+additional parameters: `author`, `url`, and `subject`. The `subject`
+parameter may also be filled with the user's comment about the change.
+
+Note: When the user edits an existing wiki page, the passed `content` will
+include only the lines that they added to the page, or modified.
+
+The hook should return `undef` on success. If the content is disallowed, it
+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
hook(type => "editcontent", id => "foo", call => \&editcontent);