forked from platypush/platypush
Made serial.plugin more robust. It can now read a JSON even if it's not all on one line and if it comes with some bogus bytes at the beginning or the end
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1 changed files with 47 additions and 4 deletions
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@ -7,6 +7,15 @@ from .. import Plugin
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class SerialPlugin(Plugin):
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"""
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The serial plugin can read data from a serial device, as long as the serial
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device returns a JSON. You can use this plugin to interact for example with
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some sensors connected through an Arduino. Just make sure that the code on
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your serial device returns JSON values. If you're using an Arduino or any
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ATMega compatible device, take a look at
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https://github.com/bblanchon/ArduinoJson.
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"""
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def __init__(self, device, baud_rate=9600, *args, **kwargs):
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super().__init__(*args, **kwargs)
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@ -14,14 +23,48 @@ class SerialPlugin(Plugin):
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self.baud_rate = baud_rate
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def _read_json(serial_port):
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n_brackets = 0
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is_escaped_ch = False
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parse_start = False
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output = bytearray()
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while True:
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ch = bytes([serial_port.read()])
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if not ch:
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break
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if ch.decode() == '{' and not is_escaped_ch:
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parse_start = True
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n_brackets += 1
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if not parse_start:
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continue
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output += ch
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if ch.decode() == '}' and not is_escaped_ch:
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n_brackets -= 1
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if n_brackets == 0:
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break
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is_escaped_ch = ch.decode() == '\\'
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return output.decode().strip()
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def get_data(self):
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ser = serial.Serial(self.device, self.baud_rate)
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try: data = ser.readline().decode('utf-8').strip()
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finally: ser.close()
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try:
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data = self._read_json(ser)
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finally:
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ser.close()
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try: data = json.loads(data)
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except: pass
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try:
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data = json.loads(data)
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except:
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self.logger.warning('Invalid JSON message from {}: {}'.
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format(self.device, data))
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return Response(output=data)
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