The linkback plugin adds Trackback and Pingback support to DokuWiki. This includes autodiscovery of track- and pingback-URLs on websites linked via an external or internal link and then sending the actual linkback as well as receiving and displaying received linkbacks. An expandable spamfilter provides protection from trackback and pingback spam. Currently, this includes

• a check whether the count of links in the excerpt exceeds a configurable amount,
• a check of the excerpt against the DokuWiki wordblock list,
• a check whether the ip of the linking page is equal to that of the submitter (moderation instead of instant deletion is enabled by default for this check, you should keep it like that),
• a check whether the linking page includes a link to the linked page in case of a trackback (where this check is not part of the protocol as compared to pingbacks) and
• support for using the Akismet webservice to check linkbacks for spam (disabled by default, you need an Akismet API key to use this feature. You can get one by registering for a blog at Wordpress.com).

It should be noted that the badbehaviour library which is incorporated into the badbehaviour plugin does not seem to be very friendly to anything remotely resembling a trackback or a pingback¹⁾ and thus will probably lead to the linkback plugin not working as intended. I'll try to look into it though.

• Version upped (2023-12-30 23:50)
• Merge pull request #18 from LouisOuellet/dev (2023-12-30 09:25)
• Removing VERSION and Reverting CHANGELOG (2023-12-30 02:32)
• Adding a check if $linkback was returned. (2023-12-29 18:03)
• Added Diagnostic Data for Trying to access array offset on value of t… (2023-12-29 17:53)
• Fixed: PHP Warning: Undefined array key "lid" in [WEBROOT]/lib/plugi… (2023-12-29 04:54)
• Update plugin.info.txt (2023-07-07 11:43)
• mail_send() replaced, some renaming (2022-08-03 20:51)

In order to send linkbacks from a wiki node, activate the corresponding checkbox in the editform.

The receiving and display of received linkbacks is handled by the syntax plugin. The following commands are recognized:

• ~~LINKBACK~~: Receive and display linkbacks.
• ~~LINKBACK:closed~~: Display already received linkbacks but don't receive new ones.
• ~~LINKBACK:off~~: Neither receive nor display linkbacks. Use this to disable linkback support in an already linkback-enabled wiki node.

The linkback plugin introduces three new events to allow for extension of its antispam-mechanisms by action plugins. These events are:

$data['linkback'] -- The linkback data as documented below
$data['page']     -- The html source as fetched from the pinging 
                     site
$data['target']   -- The wiki page that got pinged
$data['show']     -- Whether to show the linkback, defaults to true
                     and can be set in action plugins to moderate
                     the linkback
$data['log']      -- An array of lines that make up the linkback log
                     of the received linkback. Antispam plugins can
                     add their own logging output by appending lines
                     to this array.

Action plugins can register for this event to filter incoming linkbacks using both the actual linkback data as well as the source of the pinging page.

In order to report a linkback as ham (e.g. to antispam plugins using classifiers), action plugins can register for this event.

In order to report a linkback as spam (e.g. to antispam plugins using classifiers), action plugins can register for this event.

Each linkback item is represented as a hash which stores the following properties:

• lid – internal id of the linkback
• title – title
• url – url
• raw_excerpt – small excerpt of the linking page (exactly as received in the linkback)
• excerpt – small excerpt of the linking page (html tags stripped)
• blog_name – name of the linking page
• favicon – url of the linking page's favicon, or false if none could be found
• received – timestamp of the date the linkback was received
• submitter_ip – ip of the submitter
• submitter_useragent – useragent of the submitter
• submitter_referer – referer of the submitter
• type – type of the linkback, can be either trackback or pingback
• show – true if the linkback should be visible to everyone, false if it should be visible only to admins. Antispam plugins can set this to false in order to moderate a suspicious linkback.

Please don't report any bugs or feature requests here but instead use the bug tracker!