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[WIP] Read bytes in both py2 and py3 #62

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[WIP] Read bytes in both py2 and py3 #62

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d436b05
Read bytes in both py2 and py3
altendky Dec 7, 2018
19b9c85
drop a few more ord() calls
altendky Jul 19, 2020
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105 changes: 29 additions & 76 deletions sunspec/core/modbus/client.py
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Original file line number Diff line number Diff line change
Expand Up @@ -221,7 +221,7 @@ def remove_device(self, slave_id):
modbus_rtu_client_remove(self.name)

def _read(self, slave_id, addr, count, op=FUNC_READ_HOLDING, trace_func=None):
resp = ''
resp = bytearray()
len_remaining = 5
len_found = False
except_code = None
Expand All @@ -232,7 +232,7 @@ def _read(self, slave_id, addr, count, op=FUNC_READ_HOLDING, trace_func=None):
if trace_func:
s = '%s:%s[addr=%s] ->' % (self.name, str(slave_id), addr)
for c in req:
s += '%02X' % (ord(c))
s += '%02X' % (c)
trace_func(s)

self.serial.flushInput()
Expand All @@ -243,32 +243,27 @@ def _read(self, slave_id, addr, count, op=FUNC_READ_HOLDING, trace_func=None):

while len_remaining > 0:
c = self.serial.read(len_remaining)
if type(c) == bytes and sys.version_info > (3,):
temp = ""
for i in c:
temp += chr(i)
c = temp

len_read = len(c);
if len_read > 0:
resp += c
len_remaining -= len_read
if len_found is False and len(resp) >= 5:
if not (ord(resp[1]) & 0x80):
len_remaining = (ord(resp[2]) + 5) - len(resp)
if not (resp[1] & 0x80):
len_remaining = (resp[2] + 5) - len(resp)
len_found = True
else:
except_code = ord(resp[2])
except_code = resp[2]
else:
raise ModbusClientTimeout('Response timeout')

if trace_func:
s = '%s:%s[addr=%s] <--' % (self.name, str(slave_id), addr)
for c in resp:
s += '%02X' % (ord(c))
s += '%02X' % (c)
trace_func(s)

crc = (ord(resp[-2]) << 8) | ord(resp[-1])
crc = (resp[-2] << 8) | resp[-1]
if not checkCRC(resp[:-2], crc):
raise ModbusClientError('CRC error')

Expand Down Expand Up @@ -306,7 +301,7 @@ def read(self, slave_id, addr, count, op=FUNC_READ_HOLDING, trace_func=None, max
Byte string containing register contents.
"""

resp = ''
resp = bytearray()
read_count = 0
read_offset = 0

Expand All @@ -329,7 +324,7 @@ def read(self, slave_id, addr, count, op=FUNC_READ_HOLDING, trace_func=None, max
return resp

def _write(self, slave_id, addr, data, trace_func=None):
resp = ''
resp = bytearray()
len_remaining = 5
len_found = False
except_code = None
Expand All @@ -338,66 +333,50 @@ def _write(self, slave_id, addr, data, trace_func=None):
count = int(len_data/2)

req = struct.pack('>BBHHB', int(slave_id), func, int(addr), count, len_data)
if sys.version_info > (3,):
data = bytes(data, "latin-1")
req += data
req += struct.pack('>H', computeCRC(req))
if sys.version_info > (3,):
temp = ""
for i in req:
temp += chr(i)
req = temp

if trace_func:
s = '%s:%s[addr=%s] ->' % (self.name, str(slave_id), addr)
for c in req:
s += '%02X' % (ord(c))
s += '%02X' % (c)
trace_func(s)

self.serial.flushInput()
try:
if sys.version_info > (3,):
req = bytes(req, "latin-1")
self.serial.write(req)
except Exception as e:
raise ModbusClientError('Serial write error: %s' % str(e))

while len_remaining > 0:
c = self.serial.read(len_remaining)
if type(c) == bytes and sys.version_info > (3,):
temp = ""
for i in c:
temp += chr(i)
c = temp
len_read = len(c);
if len_read > 0:
resp += c
len_remaining -= len_read
if len_found is False and len(resp) >= 5:
if not (ord(resp[1]) & 0x80):
if not (resp[1] & 0x80):
len_remaining = 8 - len(resp)
len_found = True
else:
except_code = ord(resp[2])
except_code = resp[2]
else:
raise ModbusClientTimeout('Response timeout')

if trace_func:
s = '%s:%s[addr=%s] <--' % (self.name, str(slave_id), addr)
for c in resp:
s += '%02X' % (ord(c))
s += '%02X' % (c)
trace_func(s)


crc = (ord(resp[-2]) << 8) | ord(resp[-1])
crc = (resp[-2] << 8) | resp[-1]
if not checkCRC(resp[:-2], crc):
raise ModbusClientError('CRC error')

if except_code:
raise ModbusClientException('Modbus exception: %d' % (except_code))
else:
if sys.version_info > (3,):
resp = bytes(resp, 'latin-1')
resp_slave_id, resp_func, resp_addr, resp_count, resp_crc = struct.unpack('>BBHHH', resp)
if resp_slave_id != slave_id or resp_func != func or resp_addr != addr or resp_count != count:
raise ModbusClientError('Mobus response format error')
Expand Down Expand Up @@ -686,7 +665,7 @@ def disconnect(self):

def _read(self, addr, count, op=FUNC_READ_HOLDING):

resp = b''
resp = bytearray()
len_remaining = TCP_HDR_LEN + TCP_RESP_MIN_LEN
len_found = False
except_code = None
Expand All @@ -696,7 +675,7 @@ def _read(self, addr, count, op=FUNC_READ_HOLDING):
if self.trace_func:
s = '%s:%s:%s[addr=%s] ->' % (self.ipaddr, str(self.ipport), str(self.slave_id), addr)
for c in req:
s += '%02X' % (ord(c))
s += '%02X' % (c)
self.trace_func(s)

try:
Expand All @@ -717,22 +696,16 @@ def _read(self, addr, count, op=FUNC_READ_HOLDING):
else:
raise ModbusClientError('Response timeout')

if sys.version_info > (3,):
temp = ""
for i in resp:
temp += chr(i)
resp = temp

if not (ord(resp[TCP_HDR_LEN + 1]) & 0x80):
len_remaining = (ord(resp[TCP_HDR_LEN + 2]) + TCP_HDR_LEN) - len(resp)
if not (resp[TCP_HDR_LEN + 1] & 0x80):
len_remaining = (resp[TCP_HDR_LEN + 2] + TCP_HDR_LEN) - len(resp)
len_found = True
else:
except_code = ord(resp[TCP_HDR_LEN + 2])
except_code = resp[TCP_HDR_LEN + 2]

if self.trace_func:
s = '%s:%s:%s[addr=%s] <--' % (self.ipaddr, str(self.ipport), str(self.slave_id), addr)
for c in resp:
s += '%02X' % (ord(c))
s += '%02X' % (c)
self.trace_func(s)

if except_code:
Expand Down Expand Up @@ -760,7 +733,7 @@ def read(self, addr, count, op=FUNC_READ_HOLDING):
Byte string containing register contents.
"""

resp = ''
resp = bytearray()
read_count = 0
read_offset = 0
local_connect = False
Expand All @@ -787,14 +760,11 @@ def read(self, addr, count, op=FUNC_READ_HOLDING):
if local_connect:
self.disconnect()

if sys.version_info > (3,):
resp = bytes(resp, 'latin-1')

return resp

def _write(self, addr, data):

resp = ''
resp = bytearray()
len_remaining = TCP_HDR_LEN + TCP_RESP_MIN_LEN
len_found = False
except_code = None
Expand All @@ -811,7 +781,7 @@ def _write(self, addr, data):
if self.trace_func:
s = '%s:%s:%s[addr=%s] ->' % (self.ipaddr, str(self.ipport), str(self.slave_id), addr)
for c in req:
s += '%02X' % (ord(c))
s += '%02X' % (c)
self.trace_func(s)

try:
Expand All @@ -824,36 +794,24 @@ def _write(self, addr, data):
# print('c = {0}'.format(c))
len_read = len(c);
if len_read > 0:
if type(c) == bytes and sys.version_info > (3,):
temp = ""
for i in c:
temp += chr(i)
c = temp
resp += c
len_remaining -= len_read
if len_found is False and len(resp) >= TCP_HDR_LEN + TCP_RESP_MIN_LEN:
if sys.version_info > (3,):
resp = bytes(resp, "latin-1")
data_len = struct.unpack('>H', resp[TCP_HDR_O_LEN:TCP_HDR_O_LEN + 2])
len_remaining = data_len[0] - (len(resp) - TCP_HDR_LEN)
if type(resp) == bytes and sys.version_info > (3,):
temp = ""
for i in resp:
temp += chr(i)
resp = temp
else:
raise ModbusClientTimeout('Response timeout')

if not (ord(resp[TCP_HDR_LEN + 1]) & 0x80):
len_remaining = (ord(resp[TCP_HDR_LEN + 2]) + TCP_HDR_LEN) - len(resp)
if not (resp[TCP_HDR_LEN + 1] & 0x80):
len_remaining = (resp[TCP_HDR_LEN + 2] + TCP_HDR_LEN) - len(resp)
len_found = True
else:
except_code = ord(resp[TCP_HDR_LEN + 2])
except_code = resp[TCP_HDR_LEN + 2]

if self.trace_func:
s = '%s:%s:%s[addr=%s] <--' % (self.ipaddr, str(self.ipport), str(self.slave_id), addr)
for c in resp:
s += '%02X' % (ord(c))
s += '%02X' % (c)
self.trace_func(s)

if except_code:
Expand Down Expand Up @@ -1033,13 +991,8 @@ def computeCRC(data):
:returns: The calculated CRC
'''
crc = 0xffff
if type(data) == bytes and sys.version_info > (3,):
temp = ""
for i in data:
temp += chr(i)
data = temp
for a in data:
idx = __crc16_table[(crc ^ ord(a)) & 0xff];
for a in bytearray(data):
idx = __crc16_table[(crc ^ a) & 0xff];
crc = ((crc >> 8) & 0xff) ^ idx
swapped = ((crc << 8) & 0xff00) | ((crc >> 8) & 0x00ff)
return swapped
Expand Down
7 changes: 4 additions & 3 deletions sunspec/core/test/test_modbus_client.py
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Original file line number Diff line number Diff line change
Expand Up @@ -46,8 +46,9 @@ def test_modbus_client_device_rtu_read(self):
if d.client.serial.out_buf != b'\x01\x03\x9C\x40\x00\x02\xEB\x8F':
raise Exception("Modbus request mismatch")

if data != 'SunS':
raise Exception("Read data mismatch - expected: 'SunS' received: %s") % (data)
expected = b'SunS'
if data != expected:
raise Exception("Read data mismatch - expected: {expected} received: {data}".format(expected=repr(expected), data=repr(data)))

d.close()

Expand All @@ -63,7 +64,7 @@ def test_modbus_client_device_rtu_write(self):
d.client.serial.in_buf = b'\x01\x10\x9C\x40\x00\x02\x6E\x4C'
d.client.serial.out_buf = b''

d.write(40000, 'ABCD')
d.write(40000, b'ABCD')

if d.client.serial.out_buf != b'\x01\x10\x9C\x40\x00\x02\x04\x41\x42\x43\x44\x8B\xB2':
raise Exception("Modbus request mismatch")
Expand Down
2 changes: 1 addition & 1 deletion sunspec/core/test/test_util.py
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Original file line number Diff line number Diff line change
Expand Up @@ -74,7 +74,7 @@ def test_data_to_double(self):
self.assertEqual(util.data_to_double(b'\xc0\x8f\x40\x00\x00\x00\x00\x00'), float(-1000))

def test_data_to_str(self):
self.assertEqual(util.data_to_str(b'\x53\x75\x6e\x53\x70\x65\x63\x20\x54\x65\x73\x74\x00'), 'SunSpec Test')
self.assertEqual(util.data_to_str(b'\x53\x75\x6e\x53\x70\x65\x63\x20\x54\x65\x73\x74\x00'), b'SunSpec Test')


def test_s16_to_data(self):
Expand Down
10 changes: 3 additions & 7 deletions sunspec/core/util.py
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Original file line number Diff line number Diff line change
Expand Up @@ -96,14 +96,10 @@ def data_to_double(data):
return d[0]

def data_to_str(data):
data = data.rstrip(b'\0')
if len(data) == 0:
data = b'\0'

# Change the data from bytes string to regular string for python 3
# compatibility
if sys.version_info > (3,):
data = str(data, 'latin-1')

if len(data) > 1:
data = data[0] + data[1:].rstrip('\0')
return data

def s16_to_data(s16, len=None):
Expand Down