83 lines
2.0 KiB
Python
83 lines
2.0 KiB
Python
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import socket
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import json
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import base64
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#
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# Universal function to send a given amount of data to a TCP socket.
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# It returns True or False, depending on the success of
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# sending all the data to the socket.
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#
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def exact_send(dst, data):
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try:
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while len(data) != 0:
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bytes_sent = dst.send(data)
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data = data[bytes_sent:]
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return True
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except OSError:
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return False
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#
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# Universal function to receive a given amount of data from a TCP socket.
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# It returns None or data, depending on the success of
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# receiving all the required data from the socket.
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#
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def exact_recv(src, count):
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data = bytearray(0)
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while count != 0:
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new_data = src.recv(count)
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if len(new_data) == 0: return None
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data += new_data
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count -= len(new_data)
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return data
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#
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# Universal function to send a dictionary message to a TCP socket.
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# It actually transmits a JSON object, prefixed by its length (in network byte order).
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#
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# The JSON object is created from the dictionary.
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# It returns True or False, depending on the success of sending the
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# message to the socket.
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#
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def send_dict(dst, msg):
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# DEBUG print ("Send: %s" % (msg))
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data = bytes(json.dumps(msg), "utf8")
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prefixed_data = len(data).to_bytes(4, "big") + data
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return exact_send(dst, prefixed_data)
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#
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# Universal function to receive a dictionary message from a TCP socket.
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# It actually receives a JSON object, prefixed by its length (in network byte order).
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# The dictionary is created from that JSON object.
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#
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def recv_dict(src):
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prefix = exact_recv(src, 4)
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if prefix == None: return None
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length = int.from_bytes(prefix, "big")
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data = exact_recv(src, length)
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if data == None: return None
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msg = json.loads(str(data, "utf8"))
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# DEBUG print ("Recv: %s" % (msg))
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return msg
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#
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# Universal function to send and receive a dictionary to/from a TCP socket peer.
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# It returns None upon an error.
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#
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def sendrecv_dict(peer, msg):
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if send_dict(peer, msg):
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return recv_dict(peer)
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else:
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return None
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