узел-serialport объединяет фрагменты JSON

#raspberry-pi #node-serialport

#малина-пи #узел-serialport

Вопрос:

У меня есть Raspberry PI, подключенный к контроллеру ESP32 через последовательный порт

Я смог прочитать данные, полученные от последовательного (контроллер отправляет большие JSON в виде нескольких фрагментов)

 serial = new SerialPort(
    usb, {
      baudRate: 115200,
      dataBits: 8,
      parity: 'none',
      stopBits: 1,
    }, err => {
  
      if (!!err) {
        isOpened = false
        const error = 'Error opening serial port: '   u.stringify(err)
        handleError(error)
      }else{
        isOpened = true
        log.info(sig, 'Serial Port opened')
      }
  })
 

Без синтаксических анализаторов данные будут выглядеть так:

     2020/12/18 21:03:48.956 info:  [SERI write] message sent

    2020/12/18 21:03:49.020 debug:  [SERI handleData] Data: {
        "type": "answer",
        "orig_message": {
            "type": "message",
            "command":  "identify"
        },
        "timestamp":    1608239027,
        "heap-size":    284132,
        "controller":   "MM1",
        "firmware": "0.1-ex",
        "io":   [{
                "name": "I1",
                "type": "input"
            }, {
                "nam
    2020/12/18 21:03:49.037 debug:  [SERI handleData] Data: e": "I2",
                "type": "input"
            }, {
                "name": "I3",
                "type": "input"
            }, {
                "name": "I4",
                "type": "input"
            }, {
                "name": "I5",
                "type": "input"
            }, {
                "name": "I6",
                "type": "input"
            }, {
                "name": "I7",
                "type": "inp
    2020/12/18 21:03:49.059 debug:  [SERI handleData] Data: ut"
            }, {
                "name": "TO.0",
                "type": "output"
            }, {
                "name": "TO.1",
                "type": "output"
            }, {
                "name": "A0",
                "type": "analog"
            }, {
                "name": "A1",
                "type": "analog"
            }, {
                "name": "A2",
                "type": "analog"
            }, {
                "
    2020/12/18 21:03:49.071 debug:  [SERI handleData] Data: name":  "A3",
                "type": "analog"
            }, {
                "name": "A4",
                "type": "analog"
            }, {
                "name": "A5",
                "type": "analog"
            }],
        "error":    0
    }
 

После добавления анализатора (пробовал несколько разных анализаторов) данные будут отображаться в виде отдельных строк:

Анализатор:

 const parser = serial.pipe(new Readline({ delimiter: 'rn', encoding: 'utf8' }))

  parser.on('data', data => {
    handleData(data)
  })
 

Результат:

 2020/12/18 20:28:03.137 info:  [SERI write] message sent
2020/12/18 20:28:03.208 debug:  [SERI handleData] Data: {
2020/12/18 20:28:03.211 debug:  [SERI handleData] Data:     "type": "answer",
2020/12/18 20:28:03.212 debug:  [SERI handleData] Data:     "orig_message": {
2020/12/18 20:28:03.214 debug:  [SERI handleData] Data:         "type": "message",
2020/12/18 20:28:03.215 debug:  [SERI handleData] Data:         "command":  "identify"
2020/12/18 20:28:03.217 debug:  [SERI handleData] Data:     },
2020/12/18 20:28:03.218 debug:  [SERI handleData] Data:     "timestamp":    1608236881,
2020/12/18 20:28:03.220 debug:  [SERI handleData] Data:     "heap-size":    284132,
2020/12/18 20:28:03.221 debug:  [SERI handleData] Data:     "controller":   "MM1",
2020/12/18 20:28:03.222 debug:  [SERI handleData] Data:     "firmware": "0.1-ex",
2020/12/18 20:28:03.224 debug:  [SERI handleData] Data:     "io":   [{
2020/12/18 20:28:03.225 debug:  [SERI handleData] Data:             "name": "I1",
2020/12/18 20:28:03.227 debug:  [SERI handleData] Data:             "type": "input"
2020/12/18 20:28:03.228 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.235 debug:  [SERI handleData] Data:             "name": "I2",
2020/12/18 20:28:03.237 debug:  [SERI handleData] Data:             "type": "input"
2020/12/18 20:28:03.238 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.239 debug:  [SERI handleData] Data:             "name": "I3",
2020/12/18 20:28:03.240 debug:  [SERI handleData] Data:             "type": "input"
2020/12/18 20:28:03.241 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.242 debug:  [SERI handleData] Data:             "name": "I4",
2020/12/18 20:28:03.243 debug:  [SERI handleData] Data:             "type": "input"
2020/12/18 20:28:03.244 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.245 debug:  [SERI handleData] Data:             "name": "I5",
2020/12/18 20:28:03.246 debug:  [SERI handleData] Data:             "type": "input"
2020/12/18 20:28:03.247 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.248 debug:  [SERI handleData] Data:             "name": "I6",
2020/12/18 20:28:03.249 debug:  [SERI handleData] Data:             "type": "input"
2020/12/18 20:28:03.250 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.251 debug:  [SERI handleData] Data:             "name": "I7",
2020/12/18 20:28:03.257 debug:  [SERI handleData] Data:             "type": "input"
2020/12/18 20:28:03.259 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.260 debug:  [SERI handleData] Data:             "name": "TO.0",
2020/12/18 20:28:03.261 debug:  [SERI handleData] Data:             "type": "output"
2020/12/18 20:28:03.262 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.263 debug:  [SERI handleData] Data:             "name": "TO.1",
2020/12/18 20:28:03.264 debug:  [SERI handleData] Data:             "type": "output"
2020/12/18 20:28:03.264 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.265 debug:  [SERI handleData] Data:             "name": "A0",
2020/12/18 20:28:03.266 debug:  [SERI handleData] Data:             "type": "analog"
2020/12/18 20:28:03.267 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.268 debug:  [SERI handleData] Data:             "name": "A1",
2020/12/18 20:28:03.269 debug:  [SERI handleData] Data:             "type": "analog"
2020/12/18 20:28:03.270 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.271 debug:  [SERI handleData] Data:             "name": "A2",
2020/12/18 20:28:03.272 debug:  [SERI handleData] Data:             "type": "analog"
2020/12/18 20:28:03.273 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.274 debug:  [SERI handleData] Data:             "name": "A3",
2020/12/18 20:28:03.275 debug:  [SERI handleData] Data:             "type": "analog"
2020/12/18 20:28:03.276 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.277 debug:  [SERI handleData] Data:             "name": "A4",
2020/12/18 20:28:03.278 debug:  [SERI handleData] Data:             "type": "analog"
2020/12/18 20:28:03.279 debug:  [SERI handleData] Data:         }, {
2020/12/18 20:28:03.280 debug:  [SERI handleData] Data:             "name": "A5",
2020/12/18 20:28:03.280 debug:  [SERI handleData] Data:             "type": "analog"
2020/12/18 20:28:03.281 debug:  [SERI handleData] Data:         }],
2020/12/18 20:28:03.282 debug:  [SERI handleData] Data:     "error":    0
2020/12/18 20:28:03.283 debug:  [SERI handleData] Data: }
 

Итак, как я могу объединить эти фрагменты в полноценный объект JSON?

Ответ №1:

Хорошо, похоже, я нашел какое-то обходное решение, не уверен, что оно лучшее:

Я использовал библиотеку stream-json

Я добавил анализатор в последовательный поток:

 const stream = serial.pipe(parser())
 

А затем подключил ассемблер из той же библиотеки:

 const assembler = Assembler.connectTo(stream)

  assembler.on('done', asm => {
    handleData(asm.current)
  })
 

Это дает мне полный объект JavaScript:

 Data: {"type":"answer","orig_message":{"type":"message","command":"identify"},"timestamp":1608299108,"heap-size":284132,"controller":"MM1","firmware":"0.1-ex","io":[{"name":"I1","type":"input"},{"name":"I2","type":"input"},{"name":"I3","type":"input"},{"name":"I4","type":"input"},{"name":"I5","type":"input"},{"name":"I6","type":"input"},{"name":"I7","type":"input"},{"name":"TO.0","type":"output"},{"name":"TO.1","type":"output"},{"name":"A0","type":"analog"},{"name":"A1","type":"analog"},{"name":"A2","type":"analog"},{"name":"A3","type":"analog"},{"name":"A4","type":"analog"},{"name":"A5","type":"analog"}],"error":0}