arduinoWebSockets/examples/WebSocketClientSockJsAndStomp/WebSocketClientSockJsAndStomp.ino

/*
 * WebSocketClientSockJsAndStomp.ino
 * 
 * Example for connecting and maintining a connection with a SockJS+STOMP websocket connection.
 * In this example we connect to a Spring application (see https://docs.spring.io/spring/docs/current/spring-framework-reference/html/websocket.html).
 *
 *  Created on: 18.07.2017
 *  Author: Martin Becker <mgbckr>, contact: becker@informatik.uni-wuerzburg.de
 */

// CONSTANTS AND MACROS

#define DEBUG_WEBSOCKETS
#define DEBUG_WEBSOCKETS(...) Serial.printf( __VA_ARGS__ )

#define WEBSOCKETS_NETWORK_TYPE NETWORK_ESP8266
#define WEBSOCKETS_HEADERS_NO_ORIGIN

#define USE_SERIAL Serial


// LIBRARIES

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


// SETTINGS

const char* wlan_ssid             = "yourssid";
const char* wlan_password         = "password";

const char* ws_host               = "the.host.com";
const int   ws_port               = 80;

// base URL for SockJS (websocket) connection
// The complete URL will look something like this(cf. http://sockjs.github.io/sockjs-protocol/sockjs-protocol-0.3.3.html#section-36): 
// ws://<ws_host>:<ws_port>/<ws_baseurl>/<3digits>/<randomstring>/websocket
// For the default config of Spring's SockJS/STOMP support the default base URL is "/socketentry/".
const char* ws_baseurl            = "/socketentry/"; // don't forget leading and trailing "/" !!!


// VARIABLES

WebSocketsClient webSocket;


// FUNCTIONS

void webSocketEvent(WStype_t type, uint8_t * payload, size_t length) {

    switch(type) {
        case WStype_DISCONNECTED:
            USE_SERIAL.printf("[WSc] Disconnected!\n");
            break;
        case WStype_CONNECTED:
            {
                USE_SERIAL.printf("[WSc] Connected to url: %s\n",  payload);
            }
            break;
        case WStype_TEXT: {

            // #####################
            // handle STOMP protocol
            // #####################

            String text = (char*) payload; 
        
            USE_SERIAL.printf("[WSc] get text: %s\n", payload);

            if (payload[0] == 'h') {
              
              USE_SERIAL.println("Heartbeat!");
              
            } else if (payload[0] == 'o') {

              // on open connection
              char *msg = "[\"CONNECT\\naccept-version:1.1,1.0\\nheart-beat:10000,10000\\n\\n\\u0000\"]";
              webSocket.sendTXT(msg);
              
            } else if (text.startsWith("a[\"CONNECTED")) {

              // subscribe to some channels
              
              char *msg = "[\"SUBSCRIBE\\nid:sub-0\\ndestination:/user/queue/messages\\n\\n\\u0000\"]";
              webSocket.sendTXT(msg);
              delay(1000);

              // and send a message

              msg = "[\"SEND\\ndestination:/app/message\\ncontent-length:33\\n\\n{\\\"user\\\":\\\"esp\\\",\\\"message\\\":\\\"Hello!\\\"}\\u0000\"]";
              webSocket.sendTXT(msg);
              delay(1000);
            }

            break;
        } 
        case WStype_BIN:
            USE_SERIAL.printf("[WSc] get binary length: %u\n", length);
            hexdump(payload, length);

            // send data to server
            // webSocket.sendBIN(payload, length);
            break;
    }

}

void setup() {

    // setup serial

    // USE_SERIAL.begin(921600);
    USE_SERIAL.begin(115200);

//    USE_SERIAL.setDebugOutput(true);

    USE_SERIAL.println();

    for(uint8_t t = 4; t > 0; t--) {
        USE_SERIAL.printf("[SETUP] BOOT WAIT %d...\n", t);
        USE_SERIAL.flush();
        delay(1000);
    }

    // connect to WiFi

    USE_SERIAL.print("Logging into WLAN: "); Serial.print(wlan_ssid); Serial.print(" ...");
    WiFi.mode(WIFI_STA);
    WiFi.begin(wlan_ssid, wlan_password);
    
    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      USE_SERIAL.print(".");
    }
    USE_SERIAL.println(" success.");
    USE_SERIAL.print("IP: "); USE_SERIAL.println(WiFi.localIP());
    
    // #####################
    // create socket url according to SockJS protocol (cf. http://sockjs.github.io/sockjs-protocol/sockjs-protocol-0.3.3.html#section-36)
    // #####################
    String socketUrl = ws_baseurl;
    socketUrl += random(0,999);
    socketUrl += "/";
    socketUrl += random(0,999999); // should be a random string, but this works (see )
    socketUrl += "/websocket";

    // connect to websocket
    webSocket.begin(ws_host, ws_port, socketUrl);
    webSocket.onEvent(webSocketEvent);
}

void loop() {
    webSocket.loop();
}