implemented login by webview of frontend

android/app/src/main/AndroidManifest.xml

@@ -17,7 +17,8 @@
          FlutterApplication and put your custom class here. -->
     <application
         android:label="Vikunja"
-        android:icon="@mipmap/ic_launcher">
+        android:icon="@mipmap/ic_launcher"
+        android:usesCleartextTraffic="true">
         <activity
             android:name=".MainActivity"
             android:launchMode="singleTop"

lib/api/client.dart

@@ -13,6 +13,7 @@ class Client {
   bool authenticated;
 
   String get base => _base;
+  String get token => _token;
 
   Client(this._token, String base, {this.authenticated = true})
       : _base = base.endsWith('/api/v1') ? base : '$base/api/v1';

lib/pages/user/login.dart

@@ -1,10 +1,16 @@
+import 'dart:developer';
+
 import 'package:flutter/material.dart';
+import 'package:vikunja_app/api/client.dart';
+import 'package:vikunja_app/api/user_implementation.dart';
 import 'package:vikunja_app/global.dart';
+import 'package:vikunja_app/pages/user/login_webview.dart';
 import 'package:vikunja_app/pages/user/register.dart';
 import 'package:vikunja_app/theme/button.dart';
 import 'package:vikunja_app/theme/buttonText.dart';
 import 'package:vikunja_app/theme/constants.dart';
 import 'package:vikunja_app/utils/validator.dart';
+import 'package:webview_flutter/webview_flutter.dart';
 
 class LoginPage extends StatefulWidget {
   @override
@@ -129,7 +135,19 @@ class _LoginPageState extends State<LoginPage> {
                                       builder: (context) => RegisterPage())),
                               child: VikunjaButtonText('Register'),
                             )),
-                  ],
+                    Builder(builder: (context) => FancyButton(
+                        onPressed: () {
+                          if(_formKey.currentState.validate()) {
+                            Navigator.push(
+                                context,
+                                MaterialPageRoute(builder: (context) =>
+                                    LoginWithWebView(_serverController.text))).then((client) => _loginUserByClientToken(client));
+                          } else {
+                            ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text("Please enter your frontend url")));
+                          }
+                        },
+                        child: VikunjaButtonText("Login with Frontend")))
+            ],
                 ),
               ),
             ),
@@ -170,4 +188,17 @@ class _LoginPageState extends State<LoginPage> {
       });
     }
   }
+
+  _loginUserByClientToken(Client client) async {
+    setState(() => _loading = true);
+    try {
+      var newUser = await UserAPIService(client).getCurrentUser();
+      VikunjaGlobal.of(context).changeUser(
+          newUser, token: client.token, base: client.base);
+    } catch (e) {
+      log(e.toString());
+    }
+    setState(() => _loading = false);
+
+  }
 }

lib/pages/user/login_webview.dart

@@ -0,0 +1,58 @@
+import 'dart:convert';
+import 'dart:developer';
+
+import 'package:flutter/material.dart';
+import 'package:vikunja_app/models/user.dart';
+import 'package:vikunja_app/api/client.dart';
+import 'package:webview_flutter/webview_flutter.dart';
+
+class LoginWithWebView extends StatefulWidget {
+  String frontEndUrl;
+
+  LoginWithWebView(this.frontEndUrl);
+
+  @override
+  State<StatefulWidget> createState() => LoginWithWebViewState();
+}
+
+class LoginWithWebViewState extends State<LoginWithWebView> {
+
+  WebView webView;
+  WebViewController webViewController;
+
+  @override
+  void initState() {
+    super.initState();
+    webView = WebView(
+      initialUrl: widget.frontEndUrl,
+      javascriptMode: JavascriptMode.unrestricted,
+      onPageFinished: (value) => _handlePageFinished(value),
+      onWebViewCreated: (controller) => webViewController = controller,
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(),
+      body: webView
+    );
+  }
+
+  void _handlePageFinished(String value) {
+    log("handlePageFinished");
+    if(webView != null)
+      webViewController.runJavascriptReturningResult("JSON.stringify(localStorage);").then((value) {
+        if(value != "null") {
+          value = value.replaceAll("\\", "");
+          value = value.substring(1,value.length-1);
+          var json =  jsonDecode(value);
+        if (json["API_URL"] != null && json["token"] != null) {
+          Client client = Client(json["token"], json["API_URL"]);
+          Navigator.pop(context, client);
+        }
+      }
+    });
+  }
+
+}

pubspec.yaml

@@ -23,6 +23,7 @@ dependencies:
   json_serializable: 6.1.6
   petitparser: 4.1.0
   provider: 6.0.0
+  webview_flutter: 3.0.2
 
 dev_dependencies:
   flutter_test: