The message store

The message store is a collection of messages keyed off of Message-ID and X-Message-ID-Hash headers. Either of these values can be combined with the message’s List-Archive header to create a globally unique URI to the message object in the internet facing interface of the message store. The X-Message-ID-Hash is the base-32 SHA1 hash of the Message-ID.

>>> from mailman.interfaces.messages import IMessageStore
>>> from zope.component import getUtility
>>> message_store = getUtility(IMessageStore)

A message with a Message-ID header can be stored.

>>> msg = message_from_string("""\
... Subject: An important message
... Message-ID: <87myycy5eh.fsf@uwakimon.sk.tsukuba.ac.jp>
...
... This message is very important.
... """)
>>> x_message_id_hash = message_store.add(msg)
>>> print(x_message_id_hash)
AGDWSNXXKCWEILKKNYTBOHRDQGOX3Y35
>>> print(msg.as_string())
Subject: An important message
Message-ID: <87myycy5eh.fsf@uwakimon.sk.tsukuba.ac.jp>
X-Message-ID-Hash: AGDWSNXXKCWEILKKNYTBOHRDQGOX3Y35

This message is very important.

Finding messages

There are several ways to find a message given either the Message-ID or X-Message-ID-Hash headers. In either case, if no matching message is found, None is returned.

>>> print(message_store.get_message_by_id('nothing'))
None
>>> print(message_store.get_message_by_hash('nothing'))
None

Given an existing Message-ID, the message can be found.

>>> message = message_store.get_message_by_id(msg['message-id'])
>>> print(message.as_string())
Subject: An important message
Message-ID: <87myycy5eh.fsf@uwakimon.sk.tsukuba.ac.jp>
X-Message-ID-Hash: AGDWSNXXKCWEILKKNYTBOHRDQGOX3Y35

This message is very important.

Similarly, we can find messages by the X-Message-ID-Hash:

>>> message = message_store.get_message_by_hash(msg['x-message-id-hash'])
>>> print(message.as_string())
Subject: An important message
Message-ID: <87myycy5eh.fsf@uwakimon.sk.tsukuba.ac.jp>
X-Message-ID-Hash: AGDWSNXXKCWEILKKNYTBOHRDQGOX3Y35

This message is very important.

Iterating over all messages

The message store provides a means to iterate over all the messages it contains.

>>> messages = list(message_store.messages)
>>> len(messages)
1
>>> print(messages[0].as_string())
Subject: An important message
Message-ID: <87myycy5eh.fsf@uwakimon.sk.tsukuba.ac.jp>
X-Message-ID-Hash: AGDWSNXXKCWEILKKNYTBOHRDQGOX3Y35

This message is very important.

Deleting messages from the store

You delete a message from the storage service by providing the Message-ID for the message you want to delete.

>>> message_id = message['message-id']
>>> message_store.delete_message(message_id)
>>> list(message_store.messages)
[]
>>> print(message_store.get_message_by_id(message_id))
None
>>> print(message_store.get_message_by_hash(message['x-message-id-hash']))
None