Add Webserver Prometheus support for sensor, binary sensor, fan, light, cover and switch (#1032)

esphome/components/web_server/web_server.cpp

@@ -572,6 +572,11 @@ bool WebServer::canHandle(AsyncWebServerRequest *request) {
   if (request->url() == "/")
     return true;
 
+#ifdef WEBSERVER_PROMETHEUS
+  if (request->url() == "/metrics")
+    return true;
+#endif
+
 #ifdef WEBSERVER_CSS_INCLUDE
   if (request->url() == "/0.css")
     return true;
@@ -632,6 +637,13 @@ void WebServer::handleRequest(AsyncWebServerRequest *request) {
     return;
   }
 
+#ifdef WEBSERVER_PROMETHEUS
+  if (request->url() == "/metrics") {
+    this->prometheus.handle_request(request);
+    return;
+  }
+#endif
+
 #ifdef WEBSERVER_CSS_INCLUDE
   if (request->url() == "/0.css") {
     this->handle_css_request(request);