Python implementation of the Sieve email filtering language (RFC 5228).

https://github.com/garyp/sifter

FEATURES

• Supports all of the base Sieve spec from RFC 5228, except for features still listed under TODO below
• Extensions supported:
  • regex (draft-ietf-sieve-regex-01)
  • body (RFC 5173)
  • variables (RFC 5229)
  • enotify (RFC 5435, particularly the mailto method RFC 5436)
  • imap4flags (RFC 5232: setflag, addflag, removeflag; not supported: hasflags, :flags)
  • pipe (completely unofficial) usage: pipe the contents of the message to a local command
  • rewrite (completely unofficial) usage: rewrite search replace ; search and replace are expected to be regular expressions interpreted by python's re.sub routine

EXAMPLE

import email
import sifter.parser
rules = sifter.parser.parse_file(open('my_rules.sieve'))
msg = email.message_from_file(open('an_email_to_me.eml'))
msg_actions = rules.evaluate(msg)

In the above example, msg_actions is a list of actions to apply to the email message. Each action is a tuple consisting of the action name and action-specific arguments. It is up to the caller to manipulate the message and message store based on the actions returned.

WARNINGS

• No thought has been given yet to hardening against malicious user input. The current implementation is aimed at users that are running their own sieve scripts.
• The current implementation is not optimized for performance, though hopefully it's not too slow for normal inputs.

TODO

In rough order of importance:

• An example adaptor that provides Unix LDA behavior using sieve for filtering
• Base spec features not yet implemented:
  • encoded characters (section 2.4.2.4)
  • multi-line strings (section 2.4.2)
  • bracketed comments (section 2.3)
  • message uniqueness (section 2.10.3)
  • handle message loops (section 10)
  • limit abuse of redirect action (section 10)
  • address test should limit allowed headers to those that contain addresses (section 5.1)
• Make sure character sets are actually handled according to the spec
• Make string parsing comply with the grammar in section 8.1 and the features described in section 2.4.2
• Check that python's email.message implements header comparisons the same way as the sieve spec
• Make sure regular expressions are actually handled according to the extension spec
• Body extension: Cannot search prologue and epilogue of multipart parts, cannot search headers of nested message/rfc822 parts
• Add support for various extensions:
  • externally stored lists (RFC 6134)
  • relational (RFC 5231)
  • subaddress (RFC 5233)
  • copy (RFC 3894)
  • environment (RFC 5183)
  • date and index (RFC 5260)
  • editheader (RFC 5293)
  • ihave (RFC 5463)
  • mailbox metadata (RFC 5490)
  • xmpp notifications (RFC 5437)