Update to version 3.9.6

examples/Templates/Templates.ino

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-// Copyright 2016-2025 Hristo Gochkov, Mathieu Carbou, Emil Muratov
+// Copyright 2016-2026 Hristo Gochkov, Mathieu Carbou, Emil Muratov, Will Miles
 
 //
 // Shows how to serve a static and dynamic template
@@ -33,10 +33,23 @@ static const char *htmlContent PROGMEM = R"(
 
 static const size_t htmlContentLength = strlen_P(htmlContent);
 
+// Variables used for dynamic cacheable template
+static unsigned uptimeInMinutes = 0;
+static AsyncStaticWebHandler *uptimeHandler = nullptr;
+
+// Utility function for performing that update
+static void setUptimeInMinutes(unsigned t) {
+  uptimeInMinutes = t;
+  // Update caching header with a new value as well
+  if (uptimeHandler) {
+    uptimeHandler->setLastModified();
+  }
+}
+
 void setup() {
   Serial.begin(115200);
 
-#if SOC_WIFI_SUPPORTED || CONFIG_ESP_WIFI_REMOTE_ENABLED || LT_ARD_HAS_WIFI
+#if ASYNCWEBSERVER_WIFI_SUPPORTED
   WiFi.mode(WIFI_AP);
   WiFi.softAP("esp-captive");
 #endif
@@ -56,35 +69,68 @@ void setup() {
 
   // Serve the static template file
   //
+  // This call will have caching headers automatically added as it is a static 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
+  // Serve a template with dynamic content
   //
-  // 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.
+  // serveStatic recognizes that template processing is in use, and will not automatically
+  // add caching headers.
   //
-  // curl -v http://192.168.4.1/index.html
-  server.serveStatic("/index.html", LittleFS, "/template.html").setTemplateProcessor([](const String &var) -> String {
+  // curl -v http://192.168.4.1/dynamic.html
+  server.serveStatic("/dynamic.html", LittleFS, "/template.html").setTemplateProcessor([](const String &var) -> String {
     if (var == "USER") {
-      return "Bob";
+      return String("Bob ") + millis();
     }
     return emptyString;
   });
 
-  // Serve a template with dynamic content
+  // Serve a static template with a template processor
   //
-  // to serve a template with dynamic content (output changes over time), use normal
-  // Example below: content changes over tinme do not use serveStatic.
+  // By explicitly calling setLastModified() on the handler object, we enable
+  // sending the caching headers, even when a template is in use.
+  // This pattern should never be used with template data that can change.
+  // Example below: USER never changes.
   //
-  // 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 {
+  // 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 String("Bob ") + millis();
+        return "Bob";
+      }
+      return emptyString;
+    })
+    .setLastModified("Sun, 28 Sep 2025 01:02:03 GMT");
+
+  // Serve a template with dynamic content *and* caching
+  //
+  // The data used in this template is updated in loop().  loop() is then responsible
+  // for calling setLastModified() on the handler object to notify any caches that
+  // the data has changed.
+  //
+  // curl -v http://192.168.4.1/uptime.html
+  uptimeHandler = &server.serveStatic("/uptime.html", LittleFS, "/template.html").setTemplateProcessor([](const String &var) -> String {
+    if (var == "USER") {
+      return String("Bob ") + uptimeInMinutes + " minutes";
+    }
+    return emptyString;
+  });
+
+  // Serve a template with dynamic content based on user request
+  //
+  // In this case, the template is served via a callback request.  Data from the request
+  // is used to generate the template callback.
+  //
+  // curl -v -G -d "USER=Bob" http://192.168.4.1/user_request.html
+  server.on("/user_request.html", HTTP_GET, [](AsyncWebServerRequest *request) {
+    request->send(LittleFS, "/template.html", "text/html", false, [=](const String &var) -> String {
+      if (var == "USER") {
+        const AsyncWebParameter *param = request->getParam("USER");
+        if (param) {
+          return param->value();
+        }
       }
       return emptyString;
     });
@@ -96,4 +142,11 @@ void setup() {
 // not needed
 void loop() {
   delay(100);
+
+  // Compute uptime
+  unsigned currentUptimeInMinutes = millis() / (60 * 1000);
+
+  if (currentUptimeInMinutes != uptimeInMinutes) {
+    setUptimeInMinutes(currentUptimeInMinutes);
+  }
 }