// SPDX-License-Identifier: LGPL-3.0-or-later // Copyright 2016-2025 Hristo Gochkov, Mathieu Carbou, Emil Muratov // // Shows how to serve a static and dynamic template // #include #ifdef ESP32 #include #include #elif defined(ESP8266) #include #include #elif defined(TARGET_RP2040) || defined(TARGET_RP2350) || defined(PICO_RP2040) || defined(PICO_RP2350) #include #include #endif #include #include static AsyncWebServer server(80); static const char *htmlContent PROGMEM = R"(

Hello, %USER%

)"; static const size_t htmlContentLength = strlen_P(htmlContent); void setup() { Serial.begin(115200); #ifndef CONFIG_IDF_TARGET_ESP32H2 WiFi.mode(WIFI_AP); WiFi.softAP("esp-captive"); #endif #ifdef ESP32 LittleFS.begin(true); #else LittleFS.begin(); #endif { File f = LittleFS.open("/template.html", "w"); assert(f); f.print(htmlContent); f.close(); } // Serve the static template file // // curl -v http://192.168.4.1/template.html server.serveStatic("/template.html", LittleFS, "/template.html"); // Serve the static template with a template processor // // ServeStatic static is used to serve static output which never changes over time. // This special endpoints automatically adds caching headers. // If a template processor is used, it must ensure that the outputted content will always be the same over time and never changes. // Otherwise, do not use serveStatic. // Example below: IP never changes. // // curl -v http://192.168.4.1/index.html server.serveStatic("/index.html", LittleFS, "/template.html").setTemplateProcessor([](const String &var) -> String { if (var == "USER") { return "Bob"; } return emptyString; }); // Serve a template with dynamic content // // to serve a template with dynamic content (output changes over time), use normal // Example below: content changes over tinme do not use serveStatic. // // curl -v http://192.168.4.1/dynamic.html server.on("/dynamic.html", HTTP_GET, [](AsyncWebServerRequest *request) { request->send(LittleFS, "/template.html", "text/html", false, [](const String &var) -> String { if (var == "USER") { return String("Bob ") + millis(); } return emptyString; }); }); server.begin(); } // not needed void loop() { delay(100); }