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@bbx10
Last active March 3, 2023 22:13
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ESP8266 Web server with Web Socket to control an LED
/*
* ESP8266 Web server with Web Socket to control an LED.
*
* The web server keeps all clients' LED status up to date and any client may
* turn the LED on or off.
*
* For example, clientA connects and turns the LED on. This changes the word
* "LED" on the web page to the color red. When clientB connects, the word
* "LED" will be red since the server knows the LED is on. When clientB turns
* the LED off, the word LED changes color to black on clientA and clientB web
* pages.
*
* References:
*
* https://github.com/Links2004/arduinoWebSockets
*
*/
#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>
#include <WebSocketsServer.h>
#include <Hash.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>
static const char ssid[] = "********";
static const char password[] = "***************";
MDNSResponder mdns;
static void writeLED(bool);
ESP8266WiFiMulti WiFiMulti;
ESP8266WebServer server(80);
WebSocketsServer webSocket = WebSocketsServer(81);
static const char PROGMEM INDEX_HTML[] = R"rawliteral(
<!DOCTYPE html>
<html>
<head>
<meta name = "viewport" content = "width = device-width, initial-scale = 1.0, maximum-scale = 1.0, user-scalable=0">
<title>ESP8266 WebSocket Demo</title>
<style>
"body { background-color: #808080; font-family: Arial, Helvetica, Sans-Serif; Color: #000000; }"
</style>
<script>
var websock;
function start() {
websock = new WebSocket('ws://' + window.location.hostname + ':81/');
websock.onopen = function(evt) { console.log('websock open'); };
websock.onclose = function(evt) { console.log('websock close'); };
websock.onerror = function(evt) { console.log(evt); };
websock.onmessage = function(evt) {
console.log(evt);
var e = document.getElementById('ledstatus');
if (evt.data === 'ledon') {
e.style.color = 'red';
}
else if (evt.data === 'ledoff') {
e.style.color = 'black';
}
else {
console.log('unknown event');
}
};
}
function buttonclick(e) {
websock.send(e.id);
}
</script>
</head>
<body onload="javascript:start();">
<h1>ESP8266 WebSocket Demo</h1>
<div id="ledstatus"><b>LED</b></div>
<button id="ledon" type="button" onclick="buttonclick(this);">On</button>
<button id="ledoff" type="button" onclick="buttonclick(this);">Off</button>
</body>
</html>
)rawliteral";
// GPIO#0 is for Adafruit ESP8266 HUZZAH board. Your board LED might be on 13.
const int LEDPIN = 0;
// Current LED status
bool LEDStatus;
// Commands sent through Web Socket
const char LEDON[] = "ledon";
const char LEDOFF[] = "ledoff";
void webSocketEvent(uint8_t num, WStype_t type, uint8_t * payload, size_t length)
{
Serial.printf("webSocketEvent(%d, %d, ...)\r\n", num, type);
switch(type) {
case WStype_DISCONNECTED:
Serial.printf("[%u] Disconnected!\r\n", num);
break;
case WStype_CONNECTED:
{
IPAddress ip = webSocket.remoteIP(num);
Serial.printf("[%u] Connected from %d.%d.%d.%d url: %s\r\n", num, ip[0], ip[1], ip[2], ip[3], payload);
// Send the current LED status
if (LEDStatus) {
webSocket.sendTXT(num, LEDON, strlen(LEDON));
}
else {
webSocket.sendTXT(num, LEDOFF, strlen(LEDOFF));
}
}
break;
case WStype_TEXT:
Serial.printf("[%u] get Text: %s\r\n", num, payload);
if (strcmp(LEDON, (const char *)payload) == 0) {
writeLED(true);
}
else if (strcmp(LEDOFF, (const char *)payload) == 0) {
writeLED(false);
}
else {
Serial.println("Unknown command");
}
// send data to all connected clients
webSocket.broadcastTXT(payload, length);
break;
case WStype_BIN:
Serial.printf("[%u] get binary length: %u\r\n", num, length);
hexdump(payload, length);
// echo data back to browser
webSocket.sendBIN(num, payload, length);
break;
default:
Serial.printf("Invalid WStype [%d]\r\n", type);
break;
}
}
void handleRoot()
{
server.send_P(200, "text/html", INDEX_HTML);
}
void handleNotFound()
{
String message = "File Not Found\n\n";
message += "URI: ";
message += server.uri();
message += "\nMethod: ";
message += (server.method() == HTTP_GET)?"GET":"POST";
message += "\nArguments: ";
message += server.args();
message += "\n";
for (uint8_t i=0; i<server.args(); i++){
message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
}
server.send(404, "text/plain", message);
}
static void writeLED(bool LEDon)
{
LEDStatus = LEDon;
// Note inverted logic for Adafruit HUZZAH board
if (LEDon) {
digitalWrite(LEDPIN, 0);
}
else {
digitalWrite(LEDPIN, 1);
}
}
void setup()
{
pinMode(LEDPIN, OUTPUT);
writeLED(false);
Serial.begin(115200);
//Serial.setDebugOutput(true);
Serial.println();
Serial.println();
Serial.println();
for(uint8_t t = 4; t > 0; t--) {
Serial.printf("[SETUP] BOOT WAIT %d...\r\n", t);
Serial.flush();
delay(1000);
}
WiFiMulti.addAP(ssid, password);
while(WiFiMulti.run() != WL_CONNECTED) {
Serial.print(".");
delay(100);
}
Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
if (mdns.begin("espWebSock", WiFi.localIP())) {
Serial.println("MDNS responder started");
mdns.addService("http", "tcp", 80);
mdns.addService("ws", "tcp", 81);
}
else {
Serial.println("MDNS.begin failed");
}
Serial.print("Connect to http://espWebSock.local or http://");
Serial.println(WiFi.localIP());
server.on("/", handleRoot);
server.onNotFound(handleNotFound);
server.begin();
webSocket.begin();
webSocket.onEvent(webSocketEvent);
}
void loop()
{
webSocket.loop();
server.handleClient();
}
@wlvish22
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Hello,

Thanks for the websocket program to control the LED.

I have used same code to control the LED, but faced issues when two command are sent immediately one after the other. We noticed the second command gets executed first and first command later. For example, if client sent LED_ON and LED-OFF command then led remains ON till we fire any next command. We are using same 'strcmp' function to compare the text with the payload.
If we send single command everything works fine.
Any help relative to above would be highly appreciated.

Thanks,
VishP

@r0n0x
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r0n0x commented Feb 28, 2020

hi, your code causes errors, i think you might have accientally made a mistake during a revision, across all browsers the javascript locks out because "SyntaxError: An invalid or illegal string was specified" reffering to line 12 websock = new WebSocket('ws://' + window.location.hostname + ':81/');

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