does 'Frame' object support buffer interface?

[liuyangc3]

Hi,

I am using zerorpc with Python2.6 on a CentOS 6.5
I just followed the http://www.zerorpc.io/ demo and the server side got this

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/zerorpc/channel.py", line 79, in _channel_dispatcher
    event = self._events.recv()
  File "/usr/lib/python2.6/site-packages/zerorpc/events.py", line 332, in recv
    event = Event.unpack(blob)
  File "/usr/lib/python2.6/site-packages/zerorpc/events.py", line 188, in unpack
    unpacker.feed(blob)
  File "msgpack/_unpacker.pyx", line 318, in msgpack._unpacker.Unpacker.feed (msgpack/_unpacker.cpp:318)
TypeError: 'Frame' does not have the buffer interface

zerorpc use msgpack to serialize object , and , debug from IDE , found that the argument blob in unpacker.feed(blob) is class 'zmq.sugar.frame.Frame'
here is the msgpack feed() function
https://github.com/msgpack/msgpack-python/blob/master/msgpack/_unpacker.pyx#L318

def feed(self, object next_bytes):
    PyObject_GetBuffer(next_bytes, &pybuff, PyBUF_SIMPLE)

it use a C API get buffer from object

and here is what I found in /usr/lib64/python2.6/site-packages/zmq/backend/cython/message.pxd

cdef class Frame:

    cdef zmq_msg_t zmq_msg
    cdef object _data      # The actual message data as a Python object.
    cdef object _buffer    # A Python Buffer/View of the message contents
...
    cdef object _getbuffer(self) # Construct self._buffer.

seems that Frame object supoort Python Buffer interface

I am confused why feed() failed in getting buffer? Can anyone explan it?

Python 2.6.6
pyzmq 14.7.0
libzmq 4.1.2

Thanks.

[minrk]

@liuyangc3 Frame does provide the buffer interface. Here's a test script:

import sys
import zmq
import msgpack

print(sys.version)
print("libzmq-%s" % zmq.zmq_version())
print("pyzmq-%s" % zmq.pyzmq_version())
print("msgpack-%s" % ('.'.join(map(str, msgpack.version))))

ctx = zmq.Context.instance()
a = ctx.socket(zmq.PAIR)
a.bind('inproc://a')
b = ctx.socket(zmq.PAIR)
b.connect('inproc://a')

d = {'a': 5}
a.send(msgpack.packb(d))

frame = b.recv(copy=False)
print("Trying msgpack.unpackb on %r" % frame)

d2 = msgpack.unpackb(frame)
assert d2 == d, "Failed"
print("Success")

Which gives:

2.6.9 |Continuum Analytics, Inc.| (unknown, Jan 10 2014, 13:33:57) 
[GCC 4.2.1 (Apple Inc. build 5577)]
libzmq-4.0.5
pyzmq-14.7.0
msgpack-0.4.6
Trying msgpack.unpackb on <zmq.sugar.frame.Frame object at 0x10056b910>
Success

for me

[kirienko]

@minrk your test script works with ipython, but not with pypy:

$ ipython test.py 
2.7.5 (default, Jun 24 2015, 00:41:19) 
[GCC 4.8.3 20140911 (Red Hat 4.8.3-9)]
libzmq-3.2.5
pyzmq-14.3.1
msgpack-0.4.7
Trying msgpack.unpackb on <zmq.backend.cython.message.Frame object at 0x25d0dd0>
Success

For pypy (everything was installed with pypy -m pip install <package>):

$ pypy test.py 
2.7.10 (bbd45126bc691f669c4ebdfbd74456cd274c6b92, Jun 30 2016, 15:15:02)
[PyPy 5.0.1 with GCC 4.8.5 20150623 (Red Hat 4.8.5-4)]
libzmq-4.1.5
pyzmq-15.3.0
msgpack-0.4.7
Trying msgpack.unpackb on <zmq.backend.cffi.message.Frame object at 0x00007f994dc602c0>
Traceback (most recent call last):
  File "test.py", line 22, in <module>
    d2 = msgpack.unpackb(frame)
  File "/usr/lib64/pypy-5.0.1/site-packages/msgpack/fallback.py", line 96, in unpackb
    ret = unpacker._fb_unpack()
  File "/usr/lib64/pypy-5.0.1/site-packages/msgpack/fallback.py", line 498, in _fb_unpack
    typ, n, obj = self._read_header(execute, write_bytes)
  File "/usr/lib64/pypy-5.0.1/site-packages/msgpack/fallback.py", line 346, in _read_header
    c = self._fb_read(1, write_bytes)
  File "/usr/lib64/pypy-5.0.1/site-packages/msgpack/fallback.py", line 312, in _fb_read
    return buffs[self._fb_buf_i][self._fb_buf_o - n:self._fb_buf_o]
TypeError: 'Frame' object is not subscriptable