On Thu, Mar 24, 2011 at 05:41:49PM -0400, Barry Warsaw wrote:
> On Mar 24, 2011, at 05:10 PM, Steffen Daode Nurpmeso wrote:
> So, I'm not sure whether the email package can have a consistent notion of a
> message's 'size'.
> Do you have suggestions for how the email package can help with these use
> cases? Do you have specific API or implementation proposals?
An incremental package must of course have a notion of a "current
state of a message", so that all methods of an object must first
check wether they're applicable - anyway!?
Methods which can be used in multiple states need to document how
they react in each of those anyway (if behaviour changes).
So that there may be .current_parse_state() returning
a to-be-defined enum.
Or size() may return a tuple (Bool_is_final_size, current_size)
(but that's really ugly).
Beside size(), the most simple way would be to extend the
FeedParser so that it could stop in a defined way at all
boundaries of a message (i.e. Headers,Part,Part...).
That would be a state().
It would need to be restartable, i.e., .close() may remain and
return an entire message, but .last_part() or so/etc. must be
added. .feed() must return something useful, too. E.g.:
dataf = SOMERAWDATA.get_fileobject()
while 1:
l = dataf.readline()
..
parser_state = fp.feed()
if parser_state == fp.BOUNDARY_SEEN:
..
break
..
# This is a header object
# (Or, simply: Message without payload)
headerobject = fp.get_headers()
rewrite_headers(headerobject)
datachunk = prepare_as_sendfile_header_object(headerobject)
call_sendfile_with_headers_and_unchanged_rest_of_dataf
Interestingly FeedParser has almost all capabilities which are
required to do all that internally, but it does not offer it to
the outside. 8-)
Anyway, EMail is capable of many things, but it does not expose
them to the outside, so that one gets stuck soon if a special task
is to be performed. email.message_from_xy() is a fantastic
abstraction of a complex set of RFC's and real-life potholes.
On the other hand a programming package is not a shelter - you
can mess up any package which goes beyond some message_from_xy().
So i really think that it is acceptable to offer an interface
which gives you access to partially constructed objects as long as
it is well-defined in some manner.
--
Steffen Daode Nurpmeso <sdao...@gmail.com>
:wq steffen
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