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#!/usr/bin/env python
import struct
import socket
import os
headerformat = '>BBBBL'
errors = { 1 : 'unrecognized command/query header',
2 : 'illegal header path',
3 : 'illegal number',
4 : 'illegal number suffix',
5 : 'unrecognized keyword',
6 : 'string error',
7 : 'GET embedded in another message',
10 : 'arbitrary data block expected',
11 : 'non-digit character in byte count field of arbitrary data '
'block',
12 : 'EOI detected during definite length data block transfer',
13 : 'extra bytes detected during definite length data block '
'transfer' }
class Socket(object):
def __init__(self, host, port=1861, timeout=5.0):
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.connect((host, port))
self.sock.settimeout(timeout)
def clear(self, timeout=0.5):
"""
Clear any bytes in the oscilloscope's output queue by receiving
packets until the connection blocks for more than `timeout` seconds.
"""
t = self.sock.gettimeout()
self.sock.settimeout(timeout)
try:
while True:
self.sock.recv(4096)
except socket.timeout:
pass
self.sock.settimeout(t)
def send(self, msg):
"""Format and send the string `msg`."""
if not msg.endswith('\n'):
msg += '\n'
header = struct.pack(headerformat, 129, 1, 1, 0, len(msg))
self.sock.sendall(header + msg)
def check_last_command(self):
"""
Check that the last command sent was received okay; if not, raise
an exception with details about the error.
"""
self.send('cmr?')
err = int(self.recv().split(' ')[-1].rstrip('\n'))
if err in errors:
self.sock.close()
raise Exception(errors[err])
def recv(self):
"""Return a message from the scope."""
reply = ''
while True:
header = ''
while len(header) < 8:
header += self.sock.recv(8 - len(header))
operation, headerver, seqnum, spare, totalbytes = \
struct.unpack(headerformat, header)
buffer = ''
while len(buffer) < totalbytes:
buffer += self.sock.recv(totalbytes - len(buffer))
reply += buffer
if operation % 2:
break
return reply
def __del__(self):
self.sock.close()
if __name__ == '__main__':
import sys
import setup
sock = Socket(setup.scope_ip)
sock.clear()
for msg in sys.argv[1:]:
sock.send(msg)
if '?' in msg:
print repr(sock.recv())
sock.check_last_command()
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