Operating on mailing lists

The withlist command is a pretty powerful way to operate on mailing lists from the command line. This command allows you to interact with a list at a Python prompt, or process one or more mailing lists through custom made Python functions.

XXX Test the interactive operation of withlist

Getting detailed help

Because withlist is so complex, you need to request detailed help.

>>> from mailman.commands.cli_withlist import Withlist
>>> command = Withlist()

>>> class FakeArgs:
...     interactive = False
...     run = None
...     details = True
...     listname = []

>>> class FakeParser:
...     def error(self, message):
...         print(message)
>>> command.parser = FakeParser()

>>> args = FakeArgs()
>>> command.process(args)
This script provides you with a general framework for interacting with a
mailing list.
...

Running a command

By putting a Python function somewhere on your sys.path, you can have withlist call that function on a given mailing list. The function takes a single argument, the mailing list.

>>> import os, sys
>>> old_path = sys.path[:]
>>> sys.path.insert(0, config.VAR_DIR)

>>> with open(os.path.join(config.VAR_DIR, 'showme.py'), 'w') as fp:
...     print("""\
... def showme(mailing_list):
...     print("The list's name is", mailing_list.fqdn_listname)
...
... def displayname(mailing_list):
...     print("The list's display name is", mailing_list.display_name)
... """, file=fp)

If the name of the function is the same as the module, then you only need to name the function once.

>>> mlist = create_list('aardvark@example.com')
>>> args.details = False
>>> args.run = 'showme'
>>> args.listname = 'aardvark@example.com'
>>> command.process(args)
The list's name is aardvark@example.com

The function’s name can also be different than the modules name. In that case, just give the full module path name to the function you want to call.

>>> args.run = 'showme.displayname'
>>> command.process(args)
The list's display name is Aardvark

Multiple lists

You can run a command over more than one list by using a regular expression in the listname argument. To indicate a regular expression is used, the string must start with a caret.

>>> mlist_2 = create_list('badger@example.com')
>>> mlist_3 = create_list('badboys@example.com')

>>> args.listname = '^.*example.com'
>>> command.process(args)
The list's display name is Aardvark
The list's display name is Badboys
The list's display name is Badger

>>> args.listname = '^bad.*'
>>> command.process(args)
The list's display name is Badboys
The list's display name is Badger

>>> args.listname = '^foo'
>>> command.process(args)

Error handling

You get an error if you try to run a function over a non-existent mailing list.

>>> args.listname = 'mystery@example.com'
>>> command.process(args)
No such list: mystery@example.com

You also get an error if no mailing list is named.

>>> args.listname = None
>>> command.process(args)
--run requires a mailing list name

IPython

You can use IPython as the interactive shell by changing certain configuration variables in the [shell] section of your mailman.cfg file. Set use_ipython to “yes” to switch to IPython, which must be installed on your system.

Other configuration variables in the [shell] section can be used to configure other aspects of the interactive shell. You can change both the prompt and the banner.