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Interface improvements #123

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Interface improvements #123

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5c35047
generate: device: interface improvements
ES-Alexander Nov 30, 2021
a811a76
setup: update version to 0.2.0
ES-Alexander Nov 30, 2021
94d66d0
Create simplePing360Example.py
ES-Alexander Nov 30, 2021
b59625b
generate: device: add version properties
ES-Alexander Mar 20, 2022
23d55f5
generate: ping360: auto only if supported
ES-Alexander Mar 20, 2022
03fd6f8
generate: ping360: improve initialize
ES-Alexander Mar 20, 2022
9f25f00
generate: ping360: simplify imports
ES-Alexander Mar 20, 2022
58f8fc1
generate: ping360: don't reset by default
ES-Alexander Mar 20, 2022
949cd02
definitions: change to using a Payload NamedTuple
ES-Alexander Mar 20, 2022
838cf98
setup.py: require Python >= 3.6 for typing.NamedTuple
ES-Alexander Mar 20, 2022
6334ea5
pingmessage: switch to message enums
ES-Alexander Mar 20, 2022
73ac4f3
pingmessage: PingMessage -> self internally
ES-Alexander Mar 20, 2022
b9e0213
pingmessage: improve PingMessage instance creation
ES-Alexander Apr 15, 2022
37fb6c6
fixup
ES-Alexander Apr 15, 2022
09cda7e
pingmessage: improve update functions
ES-Alexander Apr 15, 2022
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160 changes: 82 additions & 78 deletions brping/pingmessage.py
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Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,8 @@
import struct
from brping import definitions
payload_dict = definitions.payload_dict_all
asciiMsgs = [definitions.COMMON_NACK, definitions.COMMON_ASCII_TEXT]
variable_msgs = [definitions.PING1D_PROFILE, definitions.PING360_DEVICE_DATA, ]
asciiMsgs = [definitions.CommonMessage.NACK, definitions.CommonMessage.ASCII_TEXT]
variable_msgs = [definitions.Ping1dMessage.PROFILE, definitions.Ping360Message.DEVICE_DATA, ]


class PingMessage(object):
Expand Down Expand Up @@ -41,7 +41,8 @@ class PingMessage(object):
## number of bytes in a checksum
checksumLength = 2

## Messge constructor
## Message constructor
# Initialize from provided data (for packing and transmitting)
#
# @par Ex request:
# @code
Expand All @@ -53,74 +54,77 @@ class PingMessage(object):
#
# @par Ex set:
# @code
# m = PingMessage(PING1D_SET_RANGE)
# m.start_mm = 1000
# m.length_mm = 2000
# m.update_checksum()
# m = PingMessage(Ping1dMessage.SET_RANGE, start_mm=1000, length_mm=2000)
# m.pack_msg_data()
# write(m.msg_data)
# @endcode
#
# @par Ex receive:
# @code
# m = PingMessage(rxByteArray)
# if m.message_id == PING1D_RANGE
# start_mm = m.start_mm
# length_mm = m.length_mm
# @endcode
def __init__(self, msg_id=0, msg_data=None):
def __init__(self, msg_id=0, dst_device_id=0, src_device_id=0, **payload_data):
## The message id
self.message_id = msg_id

## The request id for request messages
self.request_id = None

## The message destination
self.dst_device_id = 0
self.dst_device_id = dst_device_id
## The message source
self.src_device_id = 0
self.src_device_id = src_device_id
## The message checksum
self.checksum = 0

## The raw data buffer for this message
# update with pack_msg_data()
self.msg_data = None

# Constructor 1: make a pingmessage object from a binary data buffer
# (for receiving + unpacking)
if msg_data is not None:
if not self.unpack_msg_data(msg_data):
# Attempted to create an unknown message
return
# Constructor 2: make a pingmessage object cooresponding to a message
# id, with field members ready to access and populate
# (for packing + transmitting)
else:
try:
## The name of this message
self.name = payload_dict[self.message_id].name

try:
## The name of this message
self.name = payload_dict[self.message_id]["name"]
## The field names of this message
self.payload_field_names = payload_dict[self.message_id].field_names

# initialize payload field members
for attr in self.payload_field_names:
setattr(self, attr, payload_data.get(attr, 0))

## The field names of this message
self.payload_field_names = payload_dict[self.message_id]["field_names"]
# initialize vector field if present in message
if self.message_id in variable_msgs:
last_field = self.payload_field_names[-1]
# only set if not already set by user
if getattr(self, last_field) == 0:
setattr(self, last_field, bytearray())

# initialize payload field members
for attr in self.payload_field_names:
setattr(self, attr, 0)
## Number of bytes in the message payload
self.update_payload_length()

# initialize vector fields
if self.message_id in variable_msgs:
setattr(self, self.payload_field_names[-1], bytearray())
## The struct formatting string for the message payload
self.update_payload_format()

## Number of bytes in the message payload
self.update_payload_length()
# TODO pack_msg_data
# Either when data is provided, or with a 'pack' argument (default True?)
# - avoid re-updating payload length

## The struct formatting string for the message payload
self.payload_format = self.get_payload_format()
except KeyError as e:
message_id = self.message_id
raise Exception(f"{message_id = } not recognized\n{msg_data = }") from e
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f-string f'{var=}' syntax requires Python >= 3.8
-> should specify in commit message
-> should update minimum version in setup.py

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We can update to 1.* version, do all the necessary syntax corrections and move to python 3.9


# TODO handle better here, and catch Constructor 1 also
except KeyError as e:
print("message id not recognized: %d" % self.message_id, msg_data)
raise e
## Alternate constructor
# Initialize from a binary data buffer
#
# @par Ex receive:
# @code
# m = PingMessage.from_buffer(rxByteArray)
# if m.message_id == Ping1dMessage.RANGE
# start_mm = m.start_mm
# length_mm = m.length_mm
# @endcode
@classmethod
def from_buffer(cls, msg_data):
msg = cls()
if not msg.unpack_msg_data(msg_data):
# Attempted to create an unknown message
return
return msg

## Pack object attributes into self.msg_data (bytearray)
# @return self.msg_data
Expand All @@ -130,10 +134,11 @@ def pack_msg_data(self):
self.update_payload_length()

# Prepare struct packing format string
msg_format = PingMessage.endianess + PingMessage.header_format + self.get_payload_format()
self.update_payload_format()
msg_format = self.endianess + self.header_format + self.payload_format

# Prepare complete list of field names (header + payload)
attrs = PingMessage.header_field_names + payload_dict[self.message_id]["field_names"]
attrs = self.header_field_names + payload_dict[self.message_id].field_names

# Prepare iterable ordered list of values to pack
values = []
Expand All @@ -148,7 +153,7 @@ def pack_msg_data(self):
self.msg_data = bytearray(struct.pack(msg_format, *values))

# Update and append checksum
self.msg_data += bytearray(struct.pack(PingMessage.endianess + PingMessage.checksum_format, self.update_checksum()))
self.msg_data += bytearray(struct.pack(self.endianess + self.checksum_format, self.update_checksum()))

return self.msg_data

Expand All @@ -158,32 +163,32 @@ def unpack_msg_data(self, msg_data):
self.msg_data = msg_data

# Extract header
header = struct.unpack(PingMessage.endianess + PingMessage.header_format, self.msg_data[0:PingMessage.headerLength])
header = struct.unpack(self.endianess + self.header_format, self.msg_data[0:self.headerLength])

for i, attr in enumerate(PingMessage.header_field_names):
for i, attr in enumerate(self.header_field_names):
setattr(self, attr, header[i])

## The name of this message
try:
self.name = payload_dict[self.message_id]["name"]
self.name = payload_dict[self.message_id].name
except KeyError:
print("Unknown message: ", self.message_id)
return False

## The field names of this message
self.payload_field_names = payload_dict[self.message_id]["field_names"]
self.payload_field_names = payload_dict[self.message_id].field_names

if self.payload_length > 0:
## The struct formatting string for the message payload
self.payload_format = self.get_payload_format()
self.update_payload_format()

# Extract payload
try:
payload = struct.unpack(PingMessage.endianess + self.payload_format, self.msg_data[PingMessage.headerLength:PingMessage.headerLength + self.payload_length])
payload = struct.unpack(self.endianess + self.payload_format, self.msg_data[self.headerLength:self.headerLength + self.payload_length])
except Exception as e:
print("error unpacking payload: %s" % e)
print("msg_data: %s, header: %s" % (msg_data, header))
print("format: %s, buf: %s" % (PingMessage.endianess + self.payload_format, self.msg_data[PingMessage.headerLength:PingMessage.headerLength + self.payload_length]))
print("format: %s, buf: %s" % (self.endianess + self.payload_format, self.msg_data[self.headerLength:self.headerLength + self.payload_length]))
print(self.payload_format)
else: # only use payload if didn't raise exception
for i, attr in enumerate(self.payload_field_names):
Expand All @@ -196,12 +201,12 @@ def unpack_msg_data(self, msg_data):
pass

# Extract checksum
self.checksum = struct.unpack(PingMessage.endianess + PingMessage.checksum_format, self.msg_data[PingMessage.headerLength + self.payload_length: PingMessage.headerLength + self.payload_length + PingMessage.checksumLength])[0]
self.checksum = struct.unpack(self.endianess + self.checksum_format, self.msg_data[self.headerLength + self.payload_length: self.headerLength + self.payload_length + self.checksumLength])[0]
return True

## Calculate the checksum from the internal bytearray self.msg_data
def calculate_checksum(self):
return sum(self.msg_data[0:PingMessage.headerLength + self.payload_length]) & 0xffff
return sum(self.msg_data[0:self.headerLength + self.payload_length]) & 0xffff

## Update the object checksum value
# @return the object checksum value
Expand All @@ -215,30 +220,29 @@ def verify_checksum(self):

## Update the payload_length attribute with the **current** payload length, including dynamic length fields (if present)
def update_payload_length(self):
self.payload_length = payload_dict[self.message_id].payload_length

if self.message_id in variable_msgs or self.message_id in asciiMsgs:
# The last field self.payload_field_names[-1] is always the single dynamic-length field
self.payload_length = payload_dict[self.message_id]["payload_length"] + len(getattr(self, self.payload_field_names[-1]))
else:
self.payload_length = payload_dict[self.message_id]["payload_length"]
self.payload_length += len(getattr(self, self.payload_field_names[-1]))

## Get the python struct formatting string for the message payload
# @return the payload struct format string
def get_payload_format(self):
## Update the python struct formatting string for the message payload
def update_payload_format(self):
# messages with variable length fields
if self.message_id in variable_msgs or self.message_id in asciiMsgs:
var_length = self.payload_length - payload_dict[self.message_id]["payload_length"] # Subtract static length portion from payload length
if var_length <= 0:
return payload_dict[self.message_id]["format"] # variable data portion is empty

return payload_dict[self.message_id]["format"] + str(var_length) + "s"
else: # messages with a static (constant) length
return payload_dict[self.message_id]["format"]
# Subtract static length portion from payload length
var_length = self.payload_length - payload_dict[self.message_id].payload_length
if var_length > 0:
self.payload_format = payload_dict[self.message_id].format + str(var_length) + "s"
return
# messages with a static (constant) length, or empty data portion
self.payload_format = payload_dict[self.message_id].format

## Dump object into string representation
# @return string representation of the object
def __repr__(self):
header_string = "Header:"
for attr in PingMessage.header_field_names:
for attr in self.header_field_names:
header_string += " " + attr + ": " + str(getattr(self, attr))

if self.payload_length == 0: # this is a hack/guard for empty body requests
Expand All @@ -250,17 +254,17 @@ def __repr__(self):
if self.message_id in variable_msgs:

# static fields are handled as usual
for attr in payload_dict[self.message_id]["field_names"][:-1]:
for attr in payload_dict[self.message_id].field_names[:-1]:
payload_string += "\n - " + attr + ": " + str(getattr(self, attr))

# the variable length field is always the last field
attr = payload_dict[self.message_id]["field_names"][-1:][0]
attr = payload_dict[self.message_id].field_names[-1:][0]

# format this field as a list of hex values (rather than a string if we did not perform this handling)
payload_string += "\n - " + attr + ": " + str([hex(item) for item in getattr(self, attr)])

else: # handling of static length messages and text messages
for attr in payload_dict[self.message_id]["field_names"]:
for attr in payload_dict[self.message_id].field_names:
payload_string += "\n - " + attr + ": " + str(getattr(self, attr))

representation = (
Expand Down Expand Up @@ -369,7 +373,7 @@ def wait_checksum_h(self, msg_byte):
self.message_id = 0

self.buf.append(msg_byte)
self.rx_msg = PingMessage(msg_data=self.buf)
self.rx_msg = PingMessage.from_buffer(self.buf)

if self.rx_msg.verify_checksum():
self.parsed += 1
Expand Down Expand Up @@ -419,7 +423,7 @@ def parse_byte(self, msg_byte):
0x52,
4,
0,
definitions.COMMON_PROTOCOL_VERSION,
definitions.CommonMessage.PROTOCOL_VERSION,
0,
77,
211,
Expand Down
48 changes: 48 additions & 0 deletions examples/simplePing360Example.py
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Original file line number Diff line number Diff line change
@@ -0,0 +1,48 @@
#!/usr/bin/env python

#simplePing360Example.py
from brping import Ping360
import time
import argparse

##Parse Command line options
############################

parser = argparse.ArgumentParser(description="Ping python library example (Ping360).",
formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument('--device', help="Ping360 device port. E.g: /dev/ttyUSB0")
parser.add_argument('--baudrate', type=int, default=115200, help="Ping360 device baudrate. E.g: 115200")
parser.add_argument('--udp', help="Ping360 UDP server. E.g: 192.168.2.2:9092")
args = parser.parse_args()
if args.device is None and args.udp is None:
parser.print_help()
exit(1)

# Make a new Ping
device = Ping360()
if args.device is not None:
device.connect_serial(args.device, args.baudrate)
elif args.udp is not None:
(host, port) = args.udp.split(':')
device.connect_udp(host, int(port))

with device:
line = "-" * 40
print(line)
print("Starting Ping360...")
print("Press CTRL+C to exit")
print(line)

input("Press Enter to continue...")

# Read and print
while "user hasn't quit":

# Read and print distance measurements with confidence
while True:
data = myPing.get_distance()
if data:
print("Distance: %s\tConfidence: %s%%" % (data["distance"], data["confidence"]))
else:
print("Failed to get distance data")
time.sleep(0.1)
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