Tom Wang
5531da077f
app_client_blocking.py - shortening main and other DRY fixes app_server.py - adding lsock close to cleanup base line secure socket framework
151 lines
4.4 KiB
Python
151 lines
4.4 KiB
Python
# -*- coding: utf-8 -*-
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"""
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Created on Sun Mar 22 10:46:20 2020
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@author: cpan
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Simple client implementation with timeout feature to prevent hanging
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"""
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import sys
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import socket
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import json
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import io
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import struct
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def create_request(action, value):
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if action == "search":
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return dict(
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type="text/json",
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encoding="utf-8",
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content=dict(action=action, value=value),
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)
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else:
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return dict(
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type="binary/custom-client-binary-type",
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encoding="binary",
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content=bytes(action + value, encoding="utf-8"),
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)
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def _json_encode(obj, encoding):
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return json.dumps(obj, ensure_ascii=False).encode(encoding)
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def _json_decode(json_bytes, encoding):
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tiow = io.TextIOWrapper(
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io.BytesIO(json_bytes), encoding=encoding, newline=""
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)
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obj = json.load(tiow)
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tiow.close()
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return obj
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def _create_message(*, content_bytes, content_type, content_encoding):
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jsonheader = {
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"byteorder": sys.byteorder,
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"content-type": content_type,
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"content-encoding": content_encoding,
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"content-length": len(content_bytes),
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}
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jsonheader_bytes = _json_encode(jsonheader, "utf-8")
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message_hdr = struct.pack(">H", len(jsonheader_bytes))
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message = message_hdr + jsonheader_bytes + content_bytes
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return message
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def create_message(request):
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content = request["content"]
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content_type = request["type"]
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content_encoding = request["encoding"]
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if content_type == "text/json":
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req = {
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"content_bytes": _json_encode(content, content_encoding),
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"content_type": content_type,
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"content_encoding": content_encoding,
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}
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else:
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req = {
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"content_bytes": content,
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"content_type": content_type,
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"content_encoding": content_encoding,
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}
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message = _create_message(**req)
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return message
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def read_to_buffer(sock, length, buf : bytearray):
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while len(buf) < length:
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data = sock.recv(4096)
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buf += data
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def process_response(sock, addr, jsonheader, _recv_buffer):
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content_len = jsonheader["content-length"]
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read_to_buffer(sock, content_len, _recv_buffer)
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data = _recv_buffer[:content_len]
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_recv_buffer = _recv_buffer[content_len:]
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if jsonheader["content-type"] == "text/json":
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encoding = jsonheader["content-encoding"]
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response = _json_decode(data, encoding)
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print("received response", repr(response), "from", addr)
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content = response
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result = content.get("result")
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print(f"got result: {result}")
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else:
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# Binary or unknown content-type
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response = data
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print(
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f'received {jsonheader["content-type"]} response from',
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addr,
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)
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content = response
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print(f"got response: {repr(content)}")
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def main():
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HDRLEN = 2
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_recv_buffer = bytearray(b"")
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if len(sys.argv) != 5:
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print("usage:", sys.argv[0], "<host> <port> <action> <value>")
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sys.exit(1)
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host, port = sys.argv[1], int(sys.argv[2])
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action, value = sys.argv[3], sys.argv[4]
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request = create_request(action, value)
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message = create_message(request)
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addr = (host, port)
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print("starting connection to", addr)
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sock = socket.create_connection(addr)
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sock.settimeout(5)
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print(f"sending request {repr(message)} to {addr}")
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sock.sendall(message)
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# read and process protoheader (fixed length of 2 byte in network order)
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read_to_buffer(sock, HDRLEN, _recv_buffer)
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_jsonheader_len = struct.unpack(">H", _recv_buffer[:HDRLEN])[0]
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_recv_buffer = _recv_buffer[HDRLEN:]
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# read and process jsonheader
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read_to_buffer(sock, _jsonheader_len, _recv_buffer)
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jsonheader = _json_decode(_recv_buffer[:_jsonheader_len], "utf-8")
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_recv_buffer = _recv_buffer[_jsonheader_len:]
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for reqhdr in ("byteorder", "content-length", "content-type",
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"content-encoding",):
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if reqhdr not in jsonheader:
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raise ValueError(f'Missing required header "{reqhdr}".')
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# read and process response
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process_response(sock, addr, jsonheader, _recv_buffer)
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sock.shutdown(socket.SHUT_RDWR)
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sock.close()
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if __name__ == '__main__':
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main() |