esp8266_hello_web.ino

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>
 
const char* ssid     = "<REDACTED>";
const char* password = "<REDACTED>";
 
auto port = 80;
ESP8266WebServer server(port);

void handleIndex() {  
  String message = "{";
  message += "'ssid': ";
  message += ssid;
  message += ", 'ip': ";
  message += WiFi.localIP().toString();
  message += ", 'netMask': ";
  message += WiFi.subnetMask().toString();
  message += ", 'gateway': ";
  message += WiFi.gatewayIP().toString();
  message += ", 'mac': ";
  message += WiFi.macAddress();
  message += ", 'dns': ";
  message += WiFi.dnsIP().toString();
  message += ", 'hostName': ";
  message += WiFi.hostname();
  message += "}";
  
  server.send(200, "application/json", message);
}

void handleMetrics() {
  server.send(200, "application/json", "{'temperature': 10.2, 'humidity': 40.3, 'brightness': 1.4}");
}

void handleNotFound() {
  server.send(404, "text/plain", "404 not found");
}

void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println("Started");

  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
 
  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  Serial.print("Netmask: ");
  Serial.println(WiFi.subnetMask());
  Serial.print("Gateway: ");
  Serial.println(WiFi.gatewayIP());

  if (MDNS.begin("esp8266")) {
    Serial.println("MDNS responder started");
  }

  server.on("/", handleIndex);
  server.on("/metrics", handleMetrics);
  server.onNotFound(handleNotFound);

  server.begin();
  Serial.print("HTTP server started at ");
  Serial.print(WiFi.localIP());
  Serial.print(":");
  Serial.print(port);
  Serial.println("");
}
  
void loop() {
  server.handleClient();
  MDNS.update();
}