如何从Arduino连接到Action Cable Websocket？

Question

I built an app in Python Flask which controls the LED light on an Arduino through broadcasting the color selected in a form to all members of the websocket channel. I am now rebuilding in Rails and trying to determine how my Arduino can specify which channel it would like to join. I've already begun a connection to the WebSocket and seem to be getting the following back from Rails: [WSc] Received text: {"type":"ping","message":1544679171} .

Now I just need to determine how I can send in a request to specifically stream from the ArduinoChannel, but I'm not sure how to go about it. I've tried adding parameters to my webSocket.begin , but that doesn't seem to have any affect.

Below is my Arduino code for reference:

#include <ESP8266WiFi.h>
#include <WebSocketsClient.h>
#include <ArduinoJson.h>
#include <EEPROM.h>

// Initialize pins
int redpin = D0;
int greenpin = D2;
int bluepin = D4;

//// Connecting to the internet
const char* ssid = "**************";
const char* password = "******";

// Setting up the websocket client
WebSocketsClient webSocket;

// Set up the WiFi client;
WiFiClient client;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);

  pinMode(redpin, OUTPUT);
  pinMode(bluepin, OUTPUT);
  pinMode(greenpin, OUTPUT);


  delay(10);
  WiFi.begin(ssid, password);
  while(WiFi.status()!= WL_CONNECTED) {
    Serial.print(".");
    delay(500);  
  }
  Serial.println("");
  Serial.print("IP Address: ");
  Serial.print(WiFi.localIP() + "\n");
  Serial.print(WiFi.macAddress() + "\n");

  // Initializing the WS2812B communication
  setRgb(255,80,90);

  // Initializing the websocket connection

  webSocket.begin("192.168.1.93",3000, "/cable" );
//  webSocket.sendTXT('{"command":"subscribe","identifier":"{\"channel\":\"ArduinoChannel\"}"', 0);
  webSocket.onEvent(webSocketEvent);
  webSocket.setReconnectInterval(5);

}
void loop() {
  // put your main code here, to run repeatedly:
  webSocket.loop();

} 

void webSocketEvent(WStype_t type, uint8_t *payload, size_t length) {
  switch(type) {
    Serial.write(type);
    case WStype_DISCONNECTED:
      Serial.printf("[WSc] Disconnected!\n");
      break;
    case WStype_CONNECTED:
      Serial.printf("[WSc] Connected to url: %s\n", payload);
      break;
    case WStype_TEXT:
      Serial.printf("[WSc] Received text: %s\n", payload);
      DynamicJsonBuffer jBuffer;
      JsonObject &root = jBuffer.parseObject(payload);
      setRgb(root["r"],root["g"],root["b"]);
      break;
  }
}

  void setRgb(uint8_t r, uint8_t g, uint8_t b) {
  analogWrite(redpin, r);
  analogWrite(bluepin, b);
  analogWrite(greenpin, g);
  delay(10);
}

Answer 1

TL;DR:

how I can send in a request to specifically stream from the ArduinoChannel

To receive streams from ArduinoChannel , you'll need to "subscribe" by sending through Websocket connection the following the String data from Arduino-client:

"{\"command\":\"subscribe\",\"identifier\":\"{\\\"channel\\\":\\\"ArduinoChannel\\\"}\"}"

... which is almost the same as your commented out sendTXT code, but that probably you were just incorrectly "escaping" the double quotes.

References:

I traced from the JS-client version of ActionCable here

1.  App.cable.subscriptions.create('ArduinoChannel') 

2.  Subscriptions.prototype.create = function create(channelName, mixin) { var channel = channelName; var params = (typeof channel === "undefined" ? "undefined" : _typeof(channel)) === "object" ? channel : { channel: channel }; // params = { channel: "ArduinoChannel" } var subscription = new Subscription(this.consumer, params, mixin); return this.add(subscription); }; 

3.  function Subscription(consumer) { var params = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {}; var mixin = arguments[2]; classCallCheck(this, Subscription); this.consumer = consumer; this.identifier = JSON.stringify(params); extend(this, mixin); } 

4.  Subscriptions.prototype.add = function add(subscription) { this.subscriptions.push(subscription); this.consumer.ensureActiveConnection(); this.notify(subscription, "initialized"); this.sendCommand(subscription, "subscribe"); return subscription; }; 

5.  Subscriptions.prototype.sendCommand = function sendCommand(subscription, command) { var identifier = subscription.identifier; // command = "subscribe"; identifier = JSON.stringify(params) = '{"channel":"ArduinoChannel"}'; return this.consumer.send({ command: command, identifier: identifier }); }; 

6.  Consumer.prototype.send = function send(data) { // data = { command: 'subscribe', identifier: '{"channel":"ArduinoChannel"}' } return this.connection.send(data); }; 

7.  Connection.prototype.send = function send(data) { if (this.isOpen()) { // JSON.stringify(data) = '{"command":"subscribe","identifier":"{\\"channel\\":\\"ArduinoChannel\\"}"}' this.webSocket.send(JSON.stringify(data)); return true; } else { return false; } };