How can I set WordPress roles such that once a Contributor's post is scheduled to be published, they can no longer edit it?

At least for my purposes, it is absolutely essential that a Contributor be unable to edit his posts once they've been scheduled to be published, as well as actually published.

This seems like it should be simple because otherwise in a system with a lot of users a malicious user could slip under the radar w开发者_如何学Cith a sketchy post by first submitting an innocuous one and then right before it is scheduled to be published, edit it.

None of the role-editing plugins I've tried seem to have this functionality.

You need to create a filter function add hook it.

You may want to read "WordPress tip: Allow contributors to upload files" at http://www.wprecipes.com/wordpress-tip-allow-contributors-to-upload-files to get an idea.

The filter hook you'll need is the "format_to_edit" hook. Please refer to http://codex.wordpress.org/Plugin_API/Filter_Reference for details.

That filter hook isn't what you want. Let me think about it.