Hi,
Finally found the time to go through this discussion.
The first note that comes to mind is:
Although it has already been pointed out more than once that positional
arguments cannot follow keyword arguments, you both (Andrew and Vincent) keep
giving examples such as
# SYNTAX ERROR
route('sms.receive', sender=r'\+44(?P<local_number>[0-9]+)$', Consumer)
I believe the reason for that is the clash between the will to preserve the
current `route(channel, consumer)` syntax, which is like the parallel
`url(path_regex, view, **kw)` syntax, on one hand; and the instinct that the
identifying parameters should be together, on the other hand.
I think that the latter consideration prevails; unlike the kw parameters in
url(), which are essentially parameters to the view, the kw parameters
proposed for channel help select the consumer; and so they must be adjacent to
the channel name -- and hence, the consumer must be the first argument.
A second thought is about multiple keyword arguments:
It isn't clear if more than one keyword argument is allowed, and if so, what
should be the semantics of the combination. When thinking about routing, it is
almost obvious that if there are many kw arguments, they must all match for
the whole route to match. But when thinking about includes, a different
consideration arises: How do I specify routing in an app which deals with
several incompatible channels?
For argument's sake, let's say I have an app which can handle SMS's, mails and
websocket.connect's. I want it to handle all of these if they come from within
my company -- so, based on partial phone number, sender domain and client IP
addresses, respectively. Would I need to have the app's routing.py module
include()'ed three times? Or would it make more sense to give include() kw
parameters an "or" semantics -- that is, match as soon as one argument
matches?
I think both of these solutions are bad, and the only solution that makes
sense is to allow a more complex structure of argument -- so that multiple kw
args are all required to match, and for a disjunction of channels we use
positional channel-spec args -- something like,
include('my_app.routing',
chan_spec('sms.receive', sender=r'\1212555(?:[0-9]{4})$'),
chan_spec('mail.receive', sender=r'^(?:\W+)@my_org.com$),
chan_spec('websocket.connect', remote_ip='^172.10'),
)
where a set of kw parameters are considered to all belong to one implicit
chan_spec.
My 2 cents,
Shai.
