[[!template id=plugin name=comments author="[[Simon_McVittie|smcv]]"]]
[[!tag type/useful]]

This plugin adds "blog-style" comments. Unlike the wiki-style freeform 
Discussion pages, these comments are posted by a simple form, cannot later
be edited, and rss/atom feeds are provided of each page's comments.

When using this plugin, you should also enable [[htmlscrubber]] and either
[[htmltidy]] or [[htmlbalance]]. Directives are filtered out by default, to
avoid commenters slowing down the wiki by causing time-consuming
processing. As long as the recommended plugins are enabled, comment
authorship should hopefully be unforgeable by CGI users.

The intention is that on a non-wiki site (like a blog) you can lock all
pages for admin-only access, then allow otherwise unprivileged (or perhaps
even anonymous) users to comment on posts. See the documentation of the
[[lockedit]] and [[anonok]] pages for details on locking down a wiki so
users can only post comments.

Individual comments are stored as internal-use pages named something like
`page/comment_1`, `page/comment_2`, etc. These pages internally use a
`\[[!_comment]]` [[ikiwiki/directive]].

There are some global options for the setup file:

* `comments_shown_pagespec`: pages where comments will be displayed inline,
  e.g. `blog/*` or `!*/discussion`.
* `comments_open_pagespec`: pages where new comments can be posted, e.g.
  `blog/* and created_after(close_old_comments)` or `!*/discussion`
* `comments_pagename`: if this is e.g. `comment_` (the default), then
  comment pages will be named something like `page/comment_12`
* `comments_allowdirectives`: if true (default false), comments may
  contain IkiWiki [[directives|ikiwiki/directive]]
* `comments_commit`: if true (default true), comments will be committed to
  the version control system
* `comments_allowauthor`: if true (default false), anonymous commenters may
  specify a name for themselves, and the \[[!meta author]] and
  \[[!meta authorurl]] directives will not be overridden by the comments
  plugin

Known issues:

* Needs code review
* The access control via postcomment() is rather strange (see [[discussion]] for more details)
* There is some common code cargo-culted from other plugins (notably inline and editpage) which
  should probably be shared
* Joey doesn't think it should necessarily use internal pages (see [[discussion]])
* Previews always say "unknown IP address"
* Add `COMMENTOPENID`: the authenticated/verified user name, if and only if it was an OpenID
* The default template should have a (?) icon next to unauthenticated users (with the IP address
  as title) and an OpenID icon next to OpenIDs