[Evolution-hackers] server-side rule notes

[Dan Winship <danw ximian com>]

I was going to just append this to the bug, but bugzilla is down
again...

Structural differences:
      * Evo supports "all criteria match" or "any criterion matches".
      * Outlook only supports "all criteria match", BUT you can have
        multiple OR'ed items inside some rules. (Eg, "Subject contains
        'foo' OR 'bar', AND Body contains 'baz'").
      * Groupwise, Sieve, and procmail support arbitrary combinations of
        criteria
      * (Evo can also support arbitrary combinations if you enter an
        s-expression directly. Exchange can store arbitrarily complex
        rules if you don't care about them being editable in Outlook.
        But we mostly do.)

Criteria differences
      * Text fields
              * Evo supports "is", "contains", "starts with", "ends
                with", "matches regex", "matches soundex", and their
                negations
              * Exchange does not support soundex or "ends with"
                (although it does support regex, so you could hack up
                "ends with" matches with that. However...) Outlook does
                not support regex matches either.
              * Sieve supports "is", "contains", and "matches glob"
                (which could easily be used to support "starts with" and
                "ends with"), and their negations. There is a proposed
                regexp extension.
              * Groupwise supports "is", "contains", "starts with",
                "matches glob", and their negations.
              * Procmail only supports regexps, though you could fake
                everything else (except soundex) from there
      * Body
              * Sieve does not support body searches natively. (There is
                a proposed extension.)
      * Numeric fields
              * Procmail and Sieve have no relational operator support.
                (There is a Sieve extension to support it though.)
      * Date fields
              * Exchange only supports before/after specific time, not
                before/after time-relative-to-now
              * Sieve and Procmail have no explicit date support
      * Address fields
              * Outlook and Sieve allow you to match on just the
                addr-spec part of an address if you want to.
                      * Outlook does not support rules that match
                        anywhere in the address. You have to do
                        "addr-spec is", "addr-spec isn't" or
                        "display-name contains"
                      * Sieve does let you do arbitrary matches on the
                        From or To field, and also lets you do things
                        like "addr-spec matches * ximian com"
              * From what I can find on the web, GroupWise might not
                support matches on the addr-spec.
      * Specific header
              * Outlook only supports "Full headers contain / don't
                contain". (Exchange supports "Full headers match
                regex".) 
              * GroupWise doesn't appear to support arbitrary header
                matching
      * Flags/Attachments
              * Basically every system supports a different set
      * Mailing List
              * Only supported natively by Evolution, but anything that
                supports header regex matching could be taught how to
                recognize a particular list.
      * Source Account
              * Obviously doesn't make sense for server-side rules
      * Pipe Message to Shell
              * Procmail supports it, others don't

Action differences:
      * Set flags/colors/etc
              * Again, every system supports a different set.
              * Procmail can't modify the message by itself, needs to
                shell out to someone else
              * Sieve can't natively modify headers. (There is a
                proposed extension.)
      * Move/copy to folder
              * Server-side rules can only move/copy to folders in their
                store.
      * Beep, Play Sound
              * Don't make sense for server-side rules
      * Run Shell Command, Pipe Message to Shell
              * Procmail supports them, others don't

New server-side actions
      * Autoreply to message with a given template. ("If body contains
        'i click on calendar and it shows me my tasks', reply with
        ..."). Requires the ability to create a template message.
              * Outlook and GroupWise support this
              * Procmail semi-supports this via "formail"
              * Has been requested as an evo feature as well.
      * Out-of-Office/Vacation reply. (Like above, but avoids sending to
        lists, sending multiple copies to same person, etc)
              * Outlook supports this explicitly. Sieve has a proposed
                extension for it.
              * procmailex(5) shows how to do this with procmail. There
                also seems to be a standard idiom for doing it with
                GroupWise.
      * Forward/Redirect
              * Outlook supports Redirect, Forward Inline, and Forward
                as Attachment
              * Groupwise has a "Forward" rule, but the docs don't make
                it clear whether it's really Forward or Redirect.
              * Sieve supports Redirect
              * Procmail supports Redirect. Might be able to hack up
                Forward Inline via formail
      * Delegate (redirect a meeting request to someone else AND update
        the meeting info to reflect that)
              * Outlook, GroupWise
      * Automatically Accept or Decline meeting request
              * Groupwise
      * Send Message (like, if you get a message from foo, send this
        unrelated message to bar. Um... ok)
              * GroupWise
      * Reject Message (with MDN)
              * Sieve