On Wed, 7 Feb 2007 20:41:41 +0200, kgi <[EMAIL PROTECTED]> wrote:
Hi all.
I've got a bunch of Twisted XML-RPC servers that serve up a wide range of data
types include dates. Up until now I've had some hacky code to protect against
bad data types being returned to the serialization layer (Nones, unicodes,
etc). However, this code turns out to be difficult to maintain, as well as
being a modest performance hit.
I thought I see if I couldn't clean up some of the code to make it simpler and
less hacky, and I found something rather odd: a Twisted XML-RPC server
seemingly can't return a xmlrpc.DateTime object it has only just received
from the deserialization layer.
I've attached a test client, using Twisted, and two test servers, one using
Twisted, one using the standard library's SimpleXMLRPCServer.
The standard library version succeeds in returning the received
xmlrpclib.DateTime unmolested; the Twisted version complains about the
message containing unicode:
File "/usr/lib/python2.4/site-packages/twisted/internet/abstract.py",line
173, in write
raise TypeError("Data must not be unicode")
exceptions.TypeError: Data must not be unicode
This seems wrong: surely, at the very least, the serialization and
deserialization should allow a round-trip unmodified? Put a slightly
different way: I don't have a fundamental problem with the restriction that
return types not include unicode, but surely in that case, the same system
that enforces this should see to it that I don't receive such a type in the
first place (given that the original data type I created in the client was a
xmlrpclib.DateTime, which is explicitly designed for serialising over
XML-RPC!).
Are there technical/historical/political reasons for this of which I know
nothing?
Nope, it's probably just a bug. It looks like it may be a bug in the
xmlrpclib module, though. Consider this interaction:
[EMAIL PROTECTED]:~$ python
Python 2.4.3 (#2, Oct 6 2006, 07:52:30)
[GCC 4.0.3 (Ubuntu 4.0.3-1ubuntu5)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
import xmlrpclib
d1 = xmlrpclib.DateTime()
d1
<DateTime '20070207T13:51:36' at -482e1234>
s = xmlrpclib.dumps((d1,))
s
'<params>\n<param>\n<value><dateTime.iso8601>20070207T13:51:36</dateTime.iso8601></value>\n</param>\n</params>\n'
d2 = xmlrpclib.loads(s)[0][0]
d2
<DateTime u'20070207T13:51:36' at -482ddab4>
xmlrpclib.dumps((d2,))
u'<params>\n<param>\n<value><dateTime.iso8601>20070207T13:51:36</dateTime.iso8601></value>\n</param>\n</params>\n'
Twisted can probably work around the bug here, though. It would be useful
if you could file a ticket in the tracker for this (one in Twisted's and
one in Python's).
Jean-Paul
_______________________________________________
Twisted-web mailing list
[email protected]
http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-web
