/* ESP32 HTTP IoT Server Example for Wokwi.com
https://wokwi.com/arduino/projects/320964045035274834
To test, you need the Wokwi IoT Gateway, as explained here:
https://docs.wokwi.com/guides/esp32-wifi#the-private-gateway
Then start the simulation, and open http://localhost:9080
in another browser tab.
Note that the IoT Gateway requires a Wokwi Club subscription.
*/
#include <WiFi.h>
#include <WiFiClient.h>
#include <WebServer.h>
#include <uri/UriBraces.h>
#define WIFI_SSID "Wokwi-GUEST"
#define WIFI_PASSWORD ""
// Defining the WiFi channel speeds up the connection:
#define WIFI_CHANNEL 6
WebServer server(80);
const int LED1 = 26;
const int LED2 = 27;
bool led1State = false;
bool led2State = false;
void sendHtml() {
String response = R"(
<!DOCTYPE html><html>
<head>
<title>ESP32 Web Server Demo</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
html { font-family: sans-serif; text-align: center; }
body { display: inline-flex; flex-direction: column; }
h1 { margin-bottom: 1.2em; }
h2 { margin: 0; }
div { display: grid; grid-template-columns: 1fr 1fr; grid-template-rows: auto auto; grid-auto-flow: column; grid-gap: 1em; }
.btn { background-color: #5B5; border: none; color: #fff; padding: 0.5em 1em;
font-size: 2em; text-decoration: none }
.btn.OFF { background-color: #333; }
</style>
</head>
<body>
<h1>ESP32 Web Server</h1>
<div>
<h2>LED 1</h2>
<a href="/toggle/1" class="btn LED1_TEXT">LED1_TEXT</a>
<h2>LED 2</h2>
<a href="/toggle/2" class="btn LED2_TEXT">LED2_TEXT</a>
</div>
</body>
</html>
)";
response.replace("LED1_TEXT", led1State ? "ON" : "OFF");
response.replace("LED2_TEXT", led2State ? "ON" : "OFF");
server.send(200, "text/html", response);
}
byte wifi_status() {
// show WiFi status
byte status = WiFi.status();
static byte previousStatus = WL_DISCONNECTED;
if (status != previousStatus) {
previousStatus = status;
Serial.print(status);
switch (status) {
case WL_IDLE_STATUS: Serial.println(" WL_IDLE_STATUS"); break;
case WL_NO_SSID_AVAIL: Serial.println(" WL_NO_SSID_AVAIL"); break;
case WL_SCAN_COMPLETED: Serial.println(" WL_SCAN_COMPLETED"); break;
case WL_CONNECTED: Serial.println(" WL_CONNECTED"); break;
case WL_CONNECT_FAILED: Serial.println(" WL_CONNECT_FAILED"); break;
case WL_CONNECTION_LOST: Serial.println(" WL_CONNECTION_LOST"); break;
case WL_DISCONNECTED: Serial.println(" WL_DISCONNECTED"); break;
default: Serial.println(" unknown");
}
}
return status;
}
void wifi_event(WiFiEvent_t event) {
Serial.printf("[WiFi-event] event: %d -> ", event);
switch (event) {
case SYSTEM_EVENT_WIFI_READY:
Serial.println("WiFi interface ready");
break;
case SYSTEM_EVENT_SCAN_DONE:
Serial.println("Completed scan for access points");
break;
case SYSTEM_EVENT_STA_START:
Serial.println("WiFi client started");
break;
case SYSTEM_EVENT_STA_STOP:
Serial.println("WiFi clients stopped");
break;
case SYSTEM_EVENT_STA_CONNECTED:
Serial.println("Connected to access point");
break;
case SYSTEM_EVENT_STA_DISCONNECTED:
Serial.println("Disconnected from WiFi access point");
break;
case SYSTEM_EVENT_STA_AUTHMODE_CHANGE:
Serial.println("Authentication mode of access point has changed");
break;
case SYSTEM_EVENT_STA_GOT_IP:
Serial.print("Obtained IP address: ");
Serial.println(WiFi.localIP());
break;
case SYSTEM_EVENT_STA_LOST_IP:
Serial.println("Lost IP address and IP address is reset to 0");
break;
case SYSTEM_EVENT_STA_WPS_ER_SUCCESS:
Serial.println("WiFi Protected Setup (WPS): succeeded in enrollee mode");
break;
case SYSTEM_EVENT_STA_WPS_ER_FAILED:
Serial.println("WiFi Protected Setup (WPS): failed in enrollee mode");
break;
case SYSTEM_EVENT_STA_WPS_ER_TIMEOUT:
Serial.println("WiFi Protected Setup (WPS): timeout in enrollee mode");
break;
case SYSTEM_EVENT_STA_WPS_ER_PIN:
Serial.println("WiFi Protected Setup (WPS): pin code in enrollee mode");
break;
case SYSTEM_EVENT_AP_START:
Serial.println("WiFi access point started");
break;
case SYSTEM_EVENT_AP_STOP:
Serial.println("WiFi access point stopped");
break;
case SYSTEM_EVENT_AP_STACONNECTED:
Serial.println("Client connected");
break;
case SYSTEM_EVENT_AP_STADISCONNECTED:
Serial.println("Client disconnected");
break;
case SYSTEM_EVENT_AP_STAIPASSIGNED:
Serial.println("Assigned IP address to client");
break;
case SYSTEM_EVENT_AP_PROBEREQRECVED:
Serial.println("Received probe request");
break;
case SYSTEM_EVENT_GOT_IP6:
Serial.println("IPv6 is preferred");
break;
case SYSTEM_EVENT_ETH_START:
Serial.println("Ethernet started");
break;
case SYSTEM_EVENT_ETH_STOP:
Serial.println("Ethernet stopped");
break;
case SYSTEM_EVENT_ETH_CONNECTED:
Serial.println("Ethernet connected");
break;
case SYSTEM_EVENT_ETH_DISCONNECTED:
Serial.println("Ethernet disconnected");
break;
case SYSTEM_EVENT_ETH_GOT_IP:
Serial.println("Obtained IP address");
break;
default: break;
}
}
void setup(void) {
Serial.begin(115200);
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
WiFi.onEvent(wifi_event);
WiFi.begin(WIFI_SSID, WIFI_PASSWORD, WIFI_CHANNEL);
Serial.print("Connecting to WiFi ");
Serial.println(WIFI_SSID);
// Wait for connection
while (wifi_status() != WL_CONNECTED) {
delay(10);
}
server.on("/", sendHtml);
server.on(UriBraces("/toggle/{}"), []() {
String led = server.pathArg(0);
Serial.print("Toggle LED #");
Serial.println(led);
switch (led.toInt()) {
case 1:
led1State = !led1State;
digitalWrite(LED1, led1State);
break;
case 2:
led2State = !led2State;
digitalWrite(LED2, led2State);
break;
}
sendHtml();
});
server.begin();
Serial.println("HTTP server started");
}
void loop(void) {
// if WiFi is down, try reconnecting
unsigned long currentMillis = millis();
static unsigned long previousReconnect = 0;
const unsigned long interval = 5000;
if ((wifi_status() != WL_CONNECTED) && (currentMillis - previousReconnect >= interval)) {
previousReconnect = currentMillis;
Serial.print(millis());
if (0) {
// simple reconnect doesn't ever succeed on Wokwi
Serial.println(" Disconnecting and Reconnecting WiFi...");
WiFi.disconnect();
WiFi.reconnect();
} else {
// but removing the WiFi config and starting afresh does work
Serial.println(" Disconnecting and removing WiFi config...");
WiFi.disconnect(true);
Serial.println(" Reconfiguring WiFi...");
WiFi.begin(WIFI_SSID, WIFI_PASSWORD, WIFI_CHANNEL);
}
}
server.handleClient();
delay(2);
}