Added EmblaRESTAPI class w. fn to clear user data

Author: sveinbjornt

lib/embla_core.dart

@@ -24,5 +24,6 @@ library embla_core;
 export 'package:embla_core/src/session.dart' show EmblaSession, EmblaSessionState;
 export 'package:embla_core/src/config.dart' show EmblaSessionConfig;
 export 'package:embla_core/src/speech.dart' show EmblaSpeechSynthesizer;
+export 'package:embla_core/src/api.dart' show EmblaRESTAPI;
 export 'package:embla_core/src/audio.dart' show AudioPlayer;
 export 'package:embla_core/src/recorder.dart' show AudioRecorder;

lib/src/api.dart

@@ -0,0 +1,88 @@
+/*
+ * This file is part of the EmblaCore Flutter package
+ *
+ * Copyright (c) 2023 Miðeind ehf. <[email protected]>
+ * Original author: Sveinbjorn Thordarson
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/// Communication with REST API
+
+import 'dart:convert' show json;
+
+import 'package:http/http.dart' show Response;
+import 'package:http/http.dart' as http;
+
+import './common.dart';
+
+/// Send JSON POST request to API server.
+Future<Response?> _makeRequest(String apiURL, String apiKey, Map<String, dynamic> qargs,
+    [void Function(Map? result)? handler]) async {
+  dlog("Sending query POST request to $apiURL: ${qargs.toString()}");
+  Response? response;
+  try {
+    final Map<String, String> headers = {
+      "X-API-Key": apiKey,
+      "Content-Type": "application/json",
+      "Accept": "application/json"
+    };
+    response = await http
+        .post(Uri.parse(apiURL), body: json.encode(qargs), headers: headers)
+        .timeout(kRequestTimeout, onTimeout: () {
+      handler!(null);
+      return Response("Request timed out", 408);
+    });
+  } catch (e) {
+    dlog("Error while making POST request: $e");
+    response = null;
+  }
+
+  // Handle null response
+  if (response == null) {
+    handler!(null);
+    return null;
+  }
+
+  // We have a valid response object
+  dlog("Response status: ${response.statusCode}");
+//   dlog("Response body: ${response.body}");
+  if (handler != null) {
+    // Parse JSON body and feed ensuing data structure to handler function
+    dynamic arg = (response.statusCode == 200) ? json.decode(response.body) : null;
+    // JSON response should be a dict, otherwise something's gone horribly wrong
+    arg = (arg is Map) == false ? null : arg;
+    handler(arg);
+  }
+
+  return response;
+}
+
+/// Static class wrapper for functions communicating with the Embla REST API.
+class EmblaRESTAPI {
+  /// Send request to clear query history for a given device ID.
+  /// Boolean [allData] param determines whether all device-specific
+  /// data or only query history should be deleted server-side.
+  static Future<void> clearUserData(String deviceID, String apiKey,
+      {bool allData = false,
+      String serverURL = kDefaultServer,
+      void Function(Map? result)? completionHandler}) async {
+    final Map<String, String> qargs = {
+      'action': allData ? 'clear_all' : 'clear',
+      'client_id': deviceID,
+    };
+
+    final String apiURL = "$serverURL$kClearHistoryEndpoint";
+    await _makeRequest(apiURL, apiKey, qargs, completionHandler);
+  }
+}