Cached Http-Request

und gefixxt: tastur überlagert sich mit eingabefeld

lib/modules/fetchMenu.dart

@@ -1,10 +1,32 @@
+import 'dart:convert';
+import 'dart:io';
+
 import 'package:http/http.dart' as http;
+import 'package:shared_preferences/shared_preferences.dart';
 
 class FetchMenu {
+  static var lastFetch = DateTime.now();
+  static var fetched = false;
+
   static Future<List<String>> get() async {
     List<String> menus = [];
 
-    // TODO: Proto:
+    if (!fetched || DateTime.now().difference(lastFetch).inHours >= 2) {
+      menus = await fromRequest();
+      fetched = true;
+    } else {
+      menus = await fromCache();
+    }
+
+    return menus;
+  }
+
+  static Future<List<String>> fromCache() async {
+    return await loadCache();
+  }
+
+  static Future<List<String>> fromRequest() async {
+    List<String> menus = [];
     http.Response resp = await http.get(Uri.parse(
         "https://www.swfr.de/essen/mensen-cafes-speiseplaene/mensa-loerrach"));
     var content = resp.body.split("<h3>");
@@ -15,7 +37,38 @@ class FetchMenu {
         menus.add(name);
       }
     }
-    // End-Proto
+
+    await storeCache(menus);
+
+    lastFetch = DateTime.now();
+
+    return menus;
+  }
+
+  static Future<void> storeCache(List<String> menus) async {
+    var prefs = await SharedPreferences.getInstance();
+
+    for (var i = 0; i < 4; i++) {
+      prefs.setString("menuCache$i", "");
+      if (i < menus.length) {
+        prefs.setString("menuCache$i", menus[i]);
+      }
+    }
+
+
+  }
+
+  static Future<List<String>> loadCache() async {
+    var prefs = await SharedPreferences.getInstance();
+
+    List<String> menus = [];
+
+    for (var i = 0; i < 4; i++) {
+      var curr = prefs.getString("menuCache$i");
+      if (curr != "") {
+        menus.add(curr!);
+      }
+    }
 
     return menus;
   }