How to create a rule that unpublishes comments that contain links? I'm trying to create a rule that does the following.


Event: After saving new content type Forum Topic
Conditions:


User has role 'authenticated', and
Content body contains link (this is the part I can't figure out)

Actions:


Unpublish Content
Show a message on the site:


  "Your user permissions currently do not allow for you to post a forum topic that contains a link. Please remove all links from your post and re-submit by clicking the following edit link: [node:edit-url]
  
  This precaution helps us keep our forum and comments spam free. If you would like the ability to post links, please e-mail the site admin: [site:mail]"




The general idea is that I want users to register to the forum and be able to create new forum topics but not be allowed to post links since this is the whole purpose behind spam. Once they make a few quality posts, I'll move them to a trusted user group that this rule doesn't apply to, allowing them to post links.

The reason why I don't want to use Text Formats to strip out  tags is because the spam post will still be published, minus the links. This will lead to offensive, spammy posts still showing up in the forum index.
Look at honeypot and hidden capchta before getting too many rules involved.