How to connect into Action Cable websocket from Arduino? - ruby-on-rails

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
App.cable.subscriptions.create('ArduinoChannel')
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);
};
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);
}
Subscriptions.prototype.add = function add(subscription) {
this.subscriptions.push(subscription);
this.consumer.ensureActiveConnection();
this.notify(subscription, "initialized");
this.sendCommand(subscription, "subscribe");
return subscription;
};
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
});
};
Consumer.prototype.send = function send(data) {
// data = { command: 'subscribe', identifier: '{"channel":"ArduinoChannel"}' }
return this.connection.send(data);
};
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;
}
};