# Message size

The `message-size` rule matches when the posted message is bigger than a specified maximum. Generally this is used to prevent huge attachments from getting posted to the list. This value is calculated in terms of KB (1024 bytes).

    >>> from mailman.app.lifecycle import create_list
    >>> mlist = create_list('_xtest@example.com')
    >>> from mailman.config import config
    >>> rule = config.rules['max-size']
    >>> print(rule.name)
    max-size

For example, setting the maximum message size to 1 means that any message bigger than that will match the rule.

    >>> mlist.max_message_size = 1 # 1024 bytes
    >>> one_line = 'x' * 79
    >>> big_body = '\n'.join([one_line] * 15)
    >>> from mailman.testing.helpers import (specialized_message_from_string
    ...   as message_from_string)
    >>> msg = message_from_string("""\
    ... From: aperson@example.com
    ... To: _xtest@example.com
    ...
    ... """ + big_body)
    >>> rule.check(mlist, msg, {})
    True

Setting the maximum message size to zero means no size check is performed.

    >>> mlist.max_message_size = 0
    >>> rule.check(mlist, msg, {})
    False

Of course, if the maximum size is larger than the message’s size, then it’s still okay.

    >>> mlist.max_message_size = msg.original_size/1024.0 + 1
    >>> rule.check(mlist, msg, {})
    False