/usr/lib/python2.7/dist-packages/pika/frame.py is in python-pika 0.10.0-1.
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import logging
import struct
from pika import amqp_object
from pika import exceptions
from pika import spec
from pika.compat import byte
LOGGER = logging.getLogger(__name__)
class Frame(amqp_object.AMQPObject):
"""Base Frame object mapping. Defines a behavior for all child classes for
assignment of core attributes and implementation of the a core _marshal
method which child classes use to create the binary AMQP frame.
"""
NAME = 'Frame'
def __init__(self, frame_type, channel_number):
"""Create a new instance of a frame
:param int frame_type: The frame type
:param int channel_number: The channel number for the frame
"""
self.frame_type = frame_type
self.channel_number = channel_number
def _marshal(self, pieces):
"""Create the full AMQP wire protocol frame data representation
:rtype: bytes
"""
payload = b''.join(pieces)
return struct.pack('>BHI', self.frame_type, self.channel_number,
len(payload)) + payload + byte(spec.FRAME_END)
def marshal(self):
"""To be ended by child classes
:raises NotImplementedError
"""
raise NotImplementedError
class Method(Frame):
"""Base Method frame object mapping. AMQP method frames are mapped on top
of this class for creating or accessing their data and attributes.
"""
NAME = 'METHOD'
def __init__(self, channel_number, method):
"""Create a new instance of a frame
:param int channel_number: The frame type
:param pika.Spec.Class.Method method: The AMQP Class.Method
"""
Frame.__init__(self, spec.FRAME_METHOD, channel_number)
self.method = method
def marshal(self):
"""Return the AMQP binary encoded value of the frame
:rtype: str
"""
pieces = self.method.encode()
pieces.insert(0, struct.pack('>I', self.method.INDEX))
return self._marshal(pieces)
class Header(Frame):
"""Header frame object mapping. AMQP content header frames are mapped
on top of this class for creating or accessing their data and attributes.
"""
NAME = 'Header'
def __init__(self, channel_number, body_size, props):
"""Create a new instance of a AMQP ContentHeader object
:param int channel_number: The channel number for the frame
:param int body_size: The number of bytes for the body
:param pika.spec.BasicProperties props: Basic.Properties object
"""
Frame.__init__(self, spec.FRAME_HEADER, channel_number)
self.body_size = body_size
self.properties = props
def marshal(self):
"""Return the AMQP binary encoded value of the frame
:rtype: str
"""
pieces = self.properties.encode()
pieces.insert(0, struct.pack('>HxxQ', self.properties.INDEX,
self.body_size))
return self._marshal(pieces)
class Body(Frame):
"""Body frame object mapping class. AMQP content body frames are mapped on
to this base class for getting/setting of attributes/data.
"""
NAME = 'Body'
def __init__(self, channel_number, fragment):
"""
Parameters:
- channel_number: int
- fragment: unicode or str
"""
Frame.__init__(self, spec.FRAME_BODY, channel_number)
self.fragment = fragment
def marshal(self):
"""Return the AMQP binary encoded value of the frame
:rtype: str
"""
return self._marshal([self.fragment])
class Heartbeat(Frame):
"""Heartbeat frame object mapping class. AMQP Heartbeat frames are mapped
on to this class for a common access structure to the attributes/data
values.
"""
NAME = 'Heartbeat'
def __init__(self):
"""Create a new instance of the Heartbeat frame"""
Frame.__init__(self, spec.FRAME_HEARTBEAT, 0)
def marshal(self):
"""Return the AMQP binary encoded value of the frame
:rtype: str
"""
return self._marshal(list())
class ProtocolHeader(amqp_object.AMQPObject):
"""AMQP Protocol header frame class which provides a pythonic interface
for creating AMQP Protocol headers
"""
NAME = 'ProtocolHeader'
def __init__(self, major=None, minor=None, revision=None):
"""Construct a Protocol Header frame object for the specified AMQP
version
:param int major: Major version number
:param int minor: Minor version number
:param int revision: Revision
"""
self.frame_type = -1
self.major = major or spec.PROTOCOL_VERSION[0]
self.minor = minor or spec.PROTOCOL_VERSION[1]
self.revision = revision or spec.PROTOCOL_VERSION[2]
def marshal(self):
"""Return the full AMQP wire protocol frame data representation of the
ProtocolHeader frame
:rtype: str
"""
return b'AMQP' + struct.pack('BBBB', 0, self.major, self.minor,
self.revision)
def decode_frame(data_in):
"""Receives raw socket data and attempts to turn it into a frame.
Returns bytes used to make the frame and the frame
:param str data_in: The raw data stream
:rtype: tuple(bytes consumed, frame)
:raises: pika.exceptions.InvalidFrameError
"""
# Look to see if it's a protocol header frame
try:
if data_in[0:4] == b'AMQP':
major, minor, revision = struct.unpack_from('BBB', data_in, 5)
return 8, ProtocolHeader(major, minor, revision)
except (IndexError, struct.error):
return 0, None
# Get the Frame Type, Channel Number and Frame Size
try:
(frame_type, channel_number,
frame_size) = struct.unpack('>BHL', data_in[0:7])
except struct.error:
return 0, None
# Get the frame data
frame_end = spec.FRAME_HEADER_SIZE + frame_size + spec.FRAME_END_SIZE
# We don't have all of the frame yet
if frame_end > len(data_in):
return 0, None
# The Frame termination chr is wrong
if data_in[frame_end - 1:frame_end] != byte(spec.FRAME_END):
raise exceptions.InvalidFrameError("Invalid FRAME_END marker")
# Get the raw frame data
frame_data = data_in[spec.FRAME_HEADER_SIZE:frame_end - 1]
if frame_type == spec.FRAME_METHOD:
# Get the Method ID from the frame data
method_id = struct.unpack_from('>I', frame_data)[0]
# Get a Method object for this method_id
method = spec.methods[method_id]()
# Decode the content
method.decode(frame_data, 4)
# Return the amount of data consumed and the Method object
return frame_end, Method(channel_number, method)
elif frame_type == spec.FRAME_HEADER:
# Return the header class and body size
class_id, weight, body_size = struct.unpack_from('>HHQ', frame_data)
# Get the Properties type
properties = spec.props[class_id]()
# Decode the properties
out = properties.decode(frame_data[12:])
# Return a Header frame
return frame_end, Header(channel_number, body_size, properties)
elif frame_type == spec.FRAME_BODY:
# Return the amount of data consumed and the Body frame w/ data
return frame_end, Body(channel_number, frame_data)
elif frame_type == spec.FRAME_HEARTBEAT:
# Return the amount of data and a Heartbeat frame
return frame_end, Heartbeat()
raise exceptions.InvalidFrameError("Unknown frame type: %i" % frame_type)
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