Redmine

I think we should use something like a hash instead of raw project identifiers.

Something like this:

  # Generates a message id for the given object
  def message_id_for(obj)
    s = "redmine.%s.%s.%08d.%s" % [obj.project.identifier, obj.class.name, obj.id, obj.created_on.to_s]
    hash = Digest::MD5.hexdigest(s)
    host = Setting.mail_from.to_s.gsub(%r{^.*@}, '')
    "<#{hash}@#{host}>" 
  end

What do you think ?

I have no particular position on using readable string or hash. Why do you think a hash is better suited ?
Also, if using a hash, you should ensure to strip-out any character in [<>@], as specified in the internet text messages RFC.
Also, for objects having multiple revisions (edited message content, edited wiki page), message-id must be uniquified for each revision. It might be needed at some point in the future.

Why do you think a hash is better suited ?

Fixed length and [0-9a-f] only

Also, for objects having multiple revisions (edited message content, edited wiki page), message-id must be uniquified for each revision. It might be needed at some point in the future.

Good point.

Fixed length and [0-9a-f] only

Ok. This adress the fobidden chars by the way.

+1

+1