Plugin-Writing Tips

These tips may be useful to developers of SpamAssassin plugins.

Setting Output Headers and Custom Template Tags

If you want to add custom headers in the rewritten mail message, the Mail::SpamAssassin::PerMsgStatus::set_tag() API is the way to do it.

The way it works is, you add a line like this to the plugin configuration file, or the user's preferences file:

  add_header all Test-Tag the tag says _MYTAG_

and in the plugin code, call set_tag() like so:

  $permsgstatusobject->set_tag ("MYTAG", "hello world");

(obviously you want something interesting in there, like results of a scan etc.) The resulting output will look like:

  X-Spam-Status: [usual stuff]
  X-Spam-Test-Tag: the tag says hello world

You can also get the value of a tag using the Mail::SpamAssassin::PerMsgStatus::get_tag() API from inside a plugin, although note that some of the tags will not be filled in until after the scan completes, and may not be available.

In SpamAssassin 3.1.0 onwards, you can use C<set_tag> and provide a subroutine reference, like so:

  my $data = "hello world";
  $permsgstatusobject->set_tag ("MYTAG", sub {
        return $data;
      });