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Use JSON for serialising requests/responses, rather than pickle, to make C integration easier

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This commit is contained in:
Timothy Allen 2024-05-09 09:42:59 +02:00
parent dab791fb79
commit cae4d1b0a4
4 changed files with 70 additions and 37 deletions
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45
bmspy/client.py
View File

@ -2,7 +2,7 @@
# Library with socket client for use by consumers
#
import atexit, os, sys
import pickle, struct
import struct, json
import socket
@ -55,26 +55,35 @@ def socket_comms(socket_path, request_data, debug=0):
# Send request
if debug > 2:
print('socket client: sending {!r}'.format(request_data))
request = pickle.dumps(request_data)
# add length to the start of the pickled bytes, so we know how much to read on the other end
length = struct.pack('!I', len(request))
if debug > 3:
print("socket client: outgoing request length: {}, encoded as {}".format(len(request), length))
request = length + request
if debug > 4:
print("socket client: outgoing request: {}".format(request))
request = bytes()
try:
request = json.dumps(request_data).encode()
# add length to the start of the json string, so we know how much to read on the other end
length = struct.pack('!I', len(request))
if debug > 3:
print("socket client: outgoing request length: {}, encoded as {}".format(len(request), length))
request = length + request
if debug > 4:
print("socket client: outgoing request: {}".format(request))
except:
print("socket client ERROR: unable to encode request")
sys.exit(1)
sock.sendall(request)
# get length of expected pickled bytes
# get length of expected json string
response = sock.recv(struct.calcsize('!I'))
length = struct.unpack('!I', response)[0]
if debug > 4:
print("socket client: incoming length: {}, encoded as {}".format(length, response))
# read length bytes
response = sock.recv(length)
if debug > 3:
print("socket client: incoming response: {}".format(response))
response_data = pickle.loads(response)
try:
length = struct.unpack('!I', response)[0]
if debug > 4:
print("socket client: incoming length: {}, encoded as {}".format(length, response))
# read length bytes
response = sock.recv(length)
if debug > 3:
print("socket client: incoming response: {}".format(response))
response_data = json.loads(response)
except:
print("socket client ERROR: unable to decode response")
sys.exit(1)
if debug > 2:
print('socket client: received {!r}'.format(response_data))

2
bmspy/influxdb.py
View File

@ -65,7 +65,7 @@ def influxdb_create_snapshot(data, debug=0):
for kind, contains in data.items():
# discard bmspy metadata
if kind == 'client':
if kind == 'client' or kind == 'timestamp':
break
helpmsg = ''

58
bmspy/server.py
View File

@ -8,7 +8,7 @@ import os, sys, stat, time
import json
import atexit, signal
import serial, serial.rs485
import pickle, struct
import struct, json
import pprint
connected_clients = list()
@ -527,17 +527,30 @@ def collect_data(ser, debug=0):
def read_request(connection, debug=0):
# get length of expected pickle bytes
request = connection.recv(struct.calcsize('!I'))
length = struct.unpack('!I', request)[0]
# get length of expected json string
request = bytes()
try:
request = connection.recv(struct.calcsize('!I'))
except Exception as e:
raise OSError("unable to read request length from socket: {}".format(e))
try:
length = struct.unpack('!I', request)[0]
except Exception as e:
raise Exception("unable to determine request length: {}".format(e))
if debug > 4:
print("socket: incoming length: {}, encoded as {}".format(length, request))
# read length bytes
request = connection.recv(length)
try:
request = connection.recv(length)
except Exception as e:
raise OSError("unable to read socket: {}".format(e))
if debug > 3:
print("socket: incoming request: {}".format(request))
request_data = pickle.loads(request)
try:
request_data = json.loads(request)
except Exception as e:
raise Exception("unable to read incoming request: {}".format(e))
if debug > 2:
print('socket: received {!r}'.format(request_data))
@ -552,15 +565,18 @@ def send_response(connection, response_data, debug=0):
if debug > 2:
print('socket: sending {!r}'.format(response_data))
response = pickle.dumps(response_data)
# add length to the start of the pickled bytes, so we know how much to read on the other end
length = struct.pack('!I', len(response))
if debug > 4:
print('socket: sending {} data of length: {}'.format(client, length))
response = length + response
if debug > 3:
print("socket: outgoing response: {}".format(response))
return connection.sendall(response)
try:
response = json.dumps(response_data).encode()
# add length to the start of the json string, so we know how much to read on the other end
length = struct.pack('!I', len(response))
if debug > 4:
print('socket: sending {} data of length: {}'.format(client, length))
response = length + response
if debug > 3:
print("socket: outgoing response: {}".format(response))
return connection.sendall(response)
except Exception as e:
raise OSError("unable to encode response: {}".format(e))
def main():
@ -664,7 +680,12 @@ def main():
connection, client_address = sock.accept()
request_data = dict()
request_data = read_request(connection, debug)
try:
request_data = read_request(connection, debug)
except Exception as e:
print("socket ERROR: {}".format(e))
continue
client = request_data['client'] or 'unknown'
match request_data['command']:
@ -682,6 +703,9 @@ def main():
send_response(connection, {'status': 'DEREGISTERED', 'client': client}, debug)
case 'GET':
timestamp = 0
if bool(current_data) is True:
timestamp = current_data.get('timestamp', 0)
print("reading data, current timestamp is {}, time is {}".format(timestamp, time.time()))
# only get new data five seconds after the last read
if timestamp <= time.time() - 5:
@ -690,7 +714,7 @@ def main():
while bool(current_data) is False:
current_data = collect_data(ser, debug)
time.sleep(1)
timestamp = time.time()
current_data['timestamp'] = time.time()
current_data['client'] = client
send_response(connection, current_data, debug)

2
pyproject.toml
View File

@ -25,4 +25,4 @@ bmspy = "bmspy:main"
bmspy-server = "bmspy.server:main"
bmspy-influxdb = "bmspy.influxdb:main"
bmspy-prometheus = "bmspy.prometheus:main"
#bmspy-usbd = "bmspy.usbhid:main"
bmspy-usbd = "bmspy.usbhid:main"