ikiwiki/doc/plugins/attachment.mdwn

[[template id=plugin name=conditional core=1 author="[[Joey]]"]]
[[tag type/useful]]

This plugin allows files to be uploaded to the wiki over the web.

For each page `foo`, files in the subdirectory `foo/` are treated as
attachments of that page. Attachments can be uploaded and managed as
part of the interface for editing a page.

Warning: Do not enable this plugin on publically editable wikis, unless you
take care to lock down the types and sizes of files that can be uploaded.
Bear in mind that if you let anyone upload a particular kind of file
("*.mp3" files, say), then someone can abuse your wiki in at least three ways:

1. By uploading many mp3 files, wasting your disk space.
2. By uploading mp3 files that attempt to exploit security holes
   in web browsers or other players.
3. By uploading files that claim to be mp3 files, but are really some 
   other kind of file. Some web browsers may display a `foo.mp3` that
   contains html as a web page; including running any malicious javascript
   embedded in that page.

To provide a way to combat these abuses, the wiki admin can specify a
[[ikiwiki/PageSpec]] on their preferences page, to control what types of
attachments can be uploaded, and by whom. The regular [[ikiwiki/PageSpec]]
syntax is expanded with additional tests.

For example, to limit arbitrary files to 50 kilobytes, but allow
larger mp3 files to be uploaded by joey, a test like this could be
used:
  
	(user(joey) and *.mp3 and mimetype(audio/mpeg) and maxsize(15mb)) or (!ispage() and maxsize(50kb))

The following additional tests are available:

* maxsize(size)

  Tests whether the attachment is no larger than the specified size.
  The size defaults to being in bytes, but "kb", "mb", "gb" etc can be
  used to specify the units.
  
* minsize(size)

  Tests whether the attachment is no smaller than the specified size.

* ispage()

  Tests whether the attachment will be treated by ikiwiki as a wiki page.
  (Ie, if it has an extension of ".mdwn", or of any other enabled page
  format).

  So, if you don't want to allow wiki pages to be uploaded as attachments,
  use `!ispage()` ; if you only want to allow wiki pages to be uploaded
  as attachments, use `ispage()`.

* user(username)

  Tests whether the attachment is being uploaded by a user with the
  specified username. If openid is enabled, an openid can also be put here.

* ip(address)

  Tests whether the attacment is being uploaded from the specified IP
  address.

* mimetype(foo/bar)

  If the [[cpan File::MimeInfo::Magic]] perl module is installed, this
  allows checking the mime type of the attachment. You can include a glob
  in the type, for example `mimetype(image/*)`.