Add very short term (2 second) HTTP GET request cache for when multiple calls to same endpoint from redraws

lib/utils/network_utils.dart

@@ -12,6 +12,133 @@ final _logger = Logger('NetworkUtils');
 
 http.Response requestTimeout() => http.Response('Client side timeout', 408);
 
+enum _RequestType {
+  get,
+}
+
+const _expireDuration = Duration(seconds: 2);
+
+class _CachedResponse {
+  final _RequestType requestType;
+  final Uri requestUri;
+  final Map<String, dynamic> requestBody;
+  final Map<String, String> headers;
+  final http.Response response;
+  final DateTime requestTime;
+
+  _CachedResponse(
+      {required this.requestType,
+      required this.requestUri,
+      required this.requestBody,
+      required this.headers,
+      required this.response,
+      required this.requestTime});
+
+  factory _CachedResponse.requestStub(_RequestType type, Uri uri,
+          Map<String, String>? headers, Map<String, dynamic>? body) =>
+      _CachedResponse(
+        requestType: type,
+        requestUri: uri,
+        requestBody: body ?? {},
+        headers: headers ?? {},
+        response: http.Response('', 555),
+        requestTime: DateTime(0),
+      );
+
+  factory _CachedResponse.response(
+    _RequestType type,
+    Uri uri,
+    Map<String, String>? headers,
+    Map<String, dynamic>? body,
+    http.Response response,
+  ) =>
+      _CachedResponse(
+        requestType: type,
+        requestUri: uri,
+        requestBody: body ?? {},
+        headers: headers ?? {},
+        response: response,
+        requestTime: DateTime.now(),
+      );
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is _CachedResponse &&
+          runtimeType == other.runtimeType &&
+          requestType == other.requestType &&
+          requestUri == other.requestUri;
+
+  @override
+  int get hashCode => requestType.hashCode ^ requestUri.hashCode;
+}
+
+class _ExpiringRequestCache {
+  final _responses = <_CachedResponse, _CachedResponse>{};
+
+  void _cleanupCache() {
+    final expireTime = DateTime.now().subtract(_expireDuration);
+    _logger
+        .finest('Cleaning up request cache with ${_responses.length} entries');
+    _responses.removeWhere((key, value) {
+      final expired = key.requestTime.isBefore(expireTime);
+      if (expired) {
+        _logger.finest(
+            'Expiring request: ${value.requestType} => ${value.requestUri}');
+      }
+      return expired;
+    });
+    _logger.finest('Cleaned up request cache has ${_responses.length} entries');
+  }
+
+  Future<http.Response> getRequestOrExecute({
+    required Uri url,
+    Map<String, String>? headers,
+    Map<String, dynamic>? body,
+    Duration? timeout,
+  }) async {
+    _cleanupCache();
+    const type = _RequestType.get;
+    final requestStub = _CachedResponse.requestStub(
+      type,
+      url,
+      headers,
+      null,
+    );
+
+    late final http.Response response;
+    if (_responses.containsKey(requestStub)) {
+      print('Returning cached response for $type => $url');
+      response = _responses[requestStub]?.response ?? http.Response('', 555);
+    } else {
+      final request = http.get(
+        url,
+        headers: headers,
+      );
+
+      response = await request.timeout(
+        timeout ?? apiCallTimeout,
+        onTimeout: requestTimeout,
+      );
+
+      final cacheEntry = _CachedResponse.response(
+        type,
+        url,
+        headers ?? {},
+        body ?? {},
+        response,
+      );
+
+      print('Adding cached response for $type => $url');
+      _responses[cacheEntry] = cacheEntry;
+    }
+
+    return response;
+  }
+}
+
+final _cache = _ExpiringRequestCache();
+
 FutureResult<PagedResponse<String>, ExecError> getUrl(
   Uri url, {
   Map<String, String>? headers,
@@ -23,14 +150,10 @@ FutureResult<PagedResponse<String>, ExecError> getUrl(
     requestHeaders['Cookie'] = 'XDEBUG_SESSION=PHPSTORM;path=/';
   }
   try {
-    final request = http.get(
-      url,
-      headers: requestHeaders,
-    );
-
-    final response = await request.timeout(
-      timeout ?? apiCallTimeout,
-      onTimeout: requestTimeout,
+    final response = await _cache.getRequestOrExecute(
+      url: url,
+      headers: headers,
+      timeout: timeout ?? apiCallTimeout,
     );
 
     if (response.statusCode != 200) {
@@ -87,6 +210,7 @@ FutureResult<String, ExecError> putUrl(
   Uri url,
   Map<String, dynamic> body, {
   Map<String, String>? headers,
+  Duration? timeout,
 }) async {
   _logger.fine('PUT: $url \n Body: $body');
   try {
@@ -97,7 +221,7 @@ FutureResult<String, ExecError> putUrl(
     );
 
     final response = await request.timeout(
-      apiCallTimeout,
+      timeout ?? apiCallTimeout,
       onTimeout: requestTimeout,
     );
 
@@ -117,6 +241,7 @@ FutureResult<String, ExecError> deleteUrl(
   Uri url,
   Map<String, dynamic> body, {
   Map<String, String>? headers,
+  Duration? timeout,
 }) async {
   _logger.fine('DELETE: $url');
   try {
@@ -127,7 +252,7 @@ FutureResult<String, ExecError> deleteUrl(
     );
 
     final response = await request.timeout(
-      apiCallTimeout,
+      timeout ?? apiCallTimeout,
       onTimeout: requestTimeout,
     );