try out etags instead of immutable cache

interface/progmem-generator.js

@@ -2,6 +2,7 @@ import { readdirSync, existsSync, unlinkSync, readFileSync, createWriteStream }
 import { resolve, relative, sep } from 'path';
 import zlib from 'zlib';
 import mime from 'mime-types';
+import crypto from 'crypto';
 
 const ARDUINO_INCLUDES = '#include <Arduino.h>\n\n';
 const INDENT = '  ';
@@ -11,14 +12,17 @@ const bytesPerLine = 20;
 var totalSize = 0;
 
 const generateWWWClass = () =>
-  `typedef std::function<void(const String& uri, const String& contentType, const uint8_t * content, size_t len)> RouteRegistrationHandler;
+  `typedef std::function<void(const String& uri, const String& contentType, const uint8_t * content, size_t len, const String& hash)> RouteRegistrationHandler;
 // Total size is ${totalSize} bytes
 
 class WWWData {
 ${indent}public:
 ${indent.repeat(2)}static void registerRoutes(RouteRegistrationHandler handler) {
 ${fileInfo
-  .map((file) => `${indent.repeat(3)}handler("${file.uri}", "${file.mimeType}", ${file.variable}, ${file.size});`)
+  .map(
+    (file) =>
+      `${indent.repeat(3)}handler("${file.uri}", "${file.mimeType}", ${file.variable}, ${file.size}, "${file.hash}");`
+  )
   .join('\n')}
 ${indent.repeat(2)}}
 };
@@ -50,6 +54,12 @@ const writeFile = (relativeFilePath, buffer) => {
   writeStream.write('const uint8_t ' + variable + '[] = {');
   // const zipBuffer = zlib.brotliCompressSync(buffer, { quality: 1 });
   const zipBuffer = zlib.gzipSync(buffer, { level: 9 });
+
+  // create sha
+  const hashSum = crypto.createHash('sha256');
+  hashSum.update(zipBuffer);
+  const hash = hashSum.digest('hex');
+
   zipBuffer.forEach((b) => {
     if (!(size % bytesPerLine)) {
       writeStream.write('\n');
@@ -58,15 +68,19 @@ const writeFile = (relativeFilePath, buffer) => {
     writeStream.write('0x' + ('00' + b.toString(16).toUpperCase()).slice(-2) + ',');
     size++;
   });
+
   if (size % bytesPerLine) {
     writeStream.write('\n');
   }
+
   writeStream.write('};\n\n');
+
   fileInfo.push({
     uri: '/' + relativeFilePath.replace(sep, '/'),
     mimeType,
     variable,
-    size
+    size,
+    hash
   });
 
   // console.log(relativeFilePath + ' (size ' + size + ' bytes)');

lib/framework/ESP8266React.cpp

@@ -19,15 +19,32 @@ ESP8266React::ESP8266React(AsyncWebServer * server, FS * fs)
     , _restartService(server, &_securitySettingsService)
     , _factoryResetService(server, fs, &_securitySettingsService)
     , _systemStatus(server, &_securitySettingsService) {
-    // Serve static resources
-    WWWData::registerRoutes([server, this](const String & uri, const String & contentType, const uint8_t * content, size_t len) {
-        ArRequestHandlerFunction requestHandler = [contentType, content, len](AsyncWebServerRequest * request) {
+    //
+    // Serve static web resources
+    //
+
+    // Populate the last modification date based on build datetime
+    static char last_modified[50];
+    sprintf(last_modified, "%s %s CET", __DATE__, __TIME__);
+
+    WWWData::registerRoutes([server, this](const String & uri, const String & contentType, const uint8_t * content, size_t len, const String & hash) {
+        ArRequestHandlerFunction requestHandler = [contentType, content, len, hash](AsyncWebServerRequest * request) {
+            // Check if the client already has the same version and respond with a 304 (Not modified)
+            if (request->header("If-Modified-Since").indexOf(last_modified) > 0) {
+                return request->send(304);
+            } else if (request->header("If-None-Match").equals(hash)) {
+                return request->send(304);
+            }
+
             AsyncWebServerResponse * response = request->beginResponse_P(200, contentType, content, len);
             response->addHeader("Content-Encoding", "gzip");
-            response->addHeader("Cache-Control", "public, immutable, max-age=31536000");
+            // response->addHeader("Cache-Control", "public, immutable, max-age=31536000");
+            response->addHeader("Last-Modified", last_modified);
+            response->addHeader("ETag", hash);
             // response->addHeader("Content-Encoding", "br"); // only works over HTTPS
             request->send(response);
         };
+
         server->on(uri.c_str(), HTTP_GET, requestHandler);
         // Serving non matching get requests with "/index.html"
         // OPTIONS get a straight up 200 response

lib_standalone/Network.h

@@ -11,6 +11,21 @@
 #define WIFI_AP WIFI_MODE_AP
 #define WIFI_AP_STA WIFI_MODE_APSTA
 
+typedef enum {
+    WIFI_POWER_19_5dBm    = 78, // 19.5dBm
+    WIFI_POWER_19dBm      = 76, // 19dBm
+    WIFI_POWER_18_5dBm    = 74, // 18.5dBm
+    WIFI_POWER_17dBm      = 68, // 17dBm
+    WIFI_POWER_15dBm      = 60, // 15dBm
+    WIFI_POWER_13dBm      = 52, // 13dBm
+    WIFI_POWER_11dBm      = 44, // 11dBm
+    WIFI_POWER_8_5dBm     = 34, // 8.5dBm
+    WIFI_POWER_7dBm       = 28, // 7dBm
+    WIFI_POWER_5dBm       = 20, // 5dBm
+    WIFI_POWER_2dBm       = 8,  // 2dBm
+    WIFI_POWER_MINUS_1dBm = -4  // -1dBm
+} wifi_power_t;
+
 typedef enum {
     ETH_CLOCK_GPIO0_IN   = 0, /*!< RMII clock input to GPIO0 */
     ETH_CLOCK_GPIO0_OUT  = 1, /*!< RMII clock output from GPIO0 */