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 Base32 SHA1 hash of the Message-ID.
>>> from mailman.interfaces.messages import IMessageStore
>>> from zope.component import getUtility
>>> message_store = getUtility(IMessageStore)
If you try to add a message to the store which is missing the Message-ID header, you will get an exception.
>>> msg = message_from_string("""\
... Subject: An important message
...
... This message is very important.
... """)
>>> message_store.add(msg)
Traceback (most recent call last):
...
ValueError: Exactly one Message-ID header required
However, if the message has a Message-ID header, it can be stored.
>>> msg['Message-ID'] = '<87myycy5eh.fsf@uwakimon.sk.tsukuba.ac.jp>'
>>> message_store.add(msg)
'AGDWSNXXKCWEILKKNYTBOHRDQGOX3Y35'
>>> print msg.as_string()
Subject: An important message
Message-ID: <87myycy5eh.fsf@uwakimon.sk.tsukuba.ac.jp>
X-Message-ID-Hash: AGDWSNXXKCWEILKKNYTBOHRDQGOX3Y35
<BLANKLINE>
This message is very important.
<BLANKLINE>
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
<BLANKLINE>
This message is very important.
<BLANKLINE>
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
<BLANKLINE>
This message is very important.
<BLANKLINE>
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
<BLANKLINE>
This message is very important.
<BLANKLINE>
You delete a message from the storage service by providing the Message-ID for the message you want to delete. If you try to delete a Message-ID that isn’t in the store, you get an exception.
>>> message_store.delete_message('nothing')
Traceback (most recent call last):
...
LookupError: nothing
But if you delete an existing message, it really gets deleted.
>>> 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