API refactoring:

- Error if the server version is *older* than the min required version
- Display dialog boxes for different server errors

lib/api.dart

@@ -2,11 +2,15 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:flutter/cupertino.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 import 'package:image/image.dart';
 
+import 'package:InvenTree/widget/dialogs.dart';
+
 import 'package:path/path.dart' as path;
 import 'package:http/http.dart' as http;
 import 'package:shared_preferences/shared_preferences.dart';
@@ -22,18 +26,56 @@ import 'package:shared_preferences/shared_preferences.dart';
 
 class InvenTreeAPI {
 
-  // Minimum supported InvenTree server version is 0.1.1
+  // Minimum supported InvenTree server version is
-  static const List<int> MIN_SUPPORTED_VERSION = [0, 1, 1];
+  static const List<int> MIN_SUPPORTED_VERSION = [0, 1, 5];
+
+  String get _requiredVersionString => "${MIN_SUPPORTED_VERSION[0]}.${MIN_SUPPORTED_VERSION[1]}.${MIN_SUPPORTED_VERSION[2]}";
 
   bool _checkServerVersion(String version) {
-    // TODO - Decode the provided version string and determine if the server is "new" enough
+
-    return false;
+    // Provided version string should be of the format "x.y.z [...]"
+    List<String> versionSplit = version.split(' ').first.split('.');
+
+    // Extract the version number <major>.<minor>.<sub> from the string
+    if (versionSplit.length != 3) {
+      return false;
+    }
+
+    // Cast the server version to an explicit integer
+    int server_version_code = 0;
+
+    print("server version: ${version}");
+
+    server_version_code += (int.tryParse(versionSplit[0]) ?? 0) * 100 * 100;
+    server_version_code += (int.tryParse(versionSplit[1]) ?? 0) * 100;
+    server_version_code += (int.tryParse(versionSplit[2]));
+
+    print("server version code: ${server_version_code}");
+
+    int required_version_code = 0;
+
+    required_version_code += MIN_SUPPORTED_VERSION[0] * 100 * 100;
+    required_version_code += MIN_SUPPORTED_VERSION[1] * 100;
+    required_version_code += MIN_SUPPORTED_VERSION[2];
+
+    print("required version code: ${required_version_code}");
+
+    return server_version_code >= required_version_code;
   }
 
   // Endpoint for requesting an API token
   static const _URL_GET_TOKEN = "user/token/";
   static const _URL_GET_VERSION = "";
 
+  Future<void> showServerError(BuildContext context, String description) async {
+    showErrorDialog(
+      context,
+      I18N.of(context).serverError,
+      description,
+      icon: FontAwesomeIcons.server
+    );
+  }
+
   // Base URL for InvenTree API e.g. http://192.168.120.10:8000
   String _BASE_URL = "";
 
@@ -58,21 +100,13 @@ class InvenTreeAPI {
     return baseUrl + url;
   }
 
-  String get apiUrl {
+  String get apiUrl => _makeUrl("/api/");
-    return _makeUrl("/api/");
-  }
 
-  String get imageUrl {
+  String get imageUrl => _makeUrl("/image/");
-    return _makeUrl("/image/");
-  }
 
-  String makeApiUrl(String endpoint) {
+  String makeApiUrl(String endpoint) => _makeUrl("/api/" + endpoint);
-    return _makeUrl("/api/" + endpoint);
-  }
 
-  String makeUrl(String endpoint) {
+  String makeUrl(String endpoint) => _makeUrl(endpoint);
-    return _makeUrl(endpoint);
-  }
 
   String _username = "";
   String _password = "";
@@ -80,9 +114,7 @@ class InvenTreeAPI {
   // Authentication token (initially empty, must be requested)
   String _token = "";
 
-  bool isConnected() {
+  bool isConnected() => _token.isNotEmpty;
-    return _token.isNotEmpty;
-  }
 
   /*
    * Check server connection and display messages if not connected.
@@ -106,9 +138,6 @@ class InvenTreeAPI {
       return false;
     }
 
-    // Is the server version too old?
-    // TODO
-
     // Finally
     return true;
   }
@@ -138,18 +167,17 @@ class InvenTreeAPI {
 
   InvenTreeAPI._internal();
 
-  Future<bool> connect() async {
+  Future<bool> connect(BuildContext context) async {
     var prefs = await SharedPreferences.getInstance();
 
     String server = prefs.getString("server");
     String username = prefs.getString("username");
     String password = prefs.getString("password");
 
-    return connectToServer(server, username, password);
+    return connectToServer(context, server, username, password);
   }
 
-  Future<bool> connectToServer(String address, String username,
+  Future<bool> connectToServer(BuildContext context, String address, String username, String password) async {
-      String password) async {
 
     /* Address is the base address for the InvenTree server,
      * e.g. http://127.0.0.1:8000
@@ -161,9 +189,14 @@ class InvenTreeAPI {
     username = username.trim();
 
     if (address.isEmpty || username.isEmpty || password.isEmpty) {
-      errorMessage = "Server Error: Empty details supplied";
+      await showErrorDialog(
-      print(errorMessage);
+        context,
-      throw errorMessage;
+        I18N.of(context).error,
+        "Incomplete server details",
+        icon: FontAwesomeIcons.server
+      );
+
+      return false;
     }
 
     if (!address.endsWith('/')) {
@@ -185,29 +218,34 @@ class InvenTreeAPI {
 
     print("Connecting to " + apiUrl + " -> " + username + ":" + password);
 
-    // TODO - Add connection timeout
-
     var response = await get("").timeout(Duration(seconds: 10)).catchError((error) {
 
       if (error is SocketException) {
-        print("Could not connect to server");
+        errorMessage = "Could not connect to server";
         return null;
       } else if (error is TimeoutException) {
-        print("Server timeout");
+        errorMessage = "Server timeout";
         return null;
       } else {
+        // Unknown error type
+        errorMessage = error.toString();
         // Unknown error type, re-throw error
-        print("Unknown error: ${error.toString()}");
+        return null;
-        throw error;
       }
     });
 
     if (response == null) {
+      // Null (or error) response: Show dialog and exit
+
+      await showServerError(context, errorMessage);
       return false;
     }
 
     if (response.statusCode != 200) {
-      print("Invalid status code: " + response.statusCode.toString());
+      // Any status code other than 200!
+
+      // TODO: Interpret the error codes and show custom message?
+      await showServerError(context, "Invalid response code: ${response.statusCode.toString()}");
       return false;
     }
 
@@ -217,9 +255,9 @@ class InvenTreeAPI {
 
     // We expect certain response from the server
     if (!data.containsKey("server") || !data.containsKey("version")) {
-      errorMessage = "Server resonse contained incorrect data";
+
-      print(errorMessage);
+      await showServerError(context, "Server response missing required fields");
-      throw errorMessage;
+      return false;
     }
 
     print("Server: " + data["server"]);
@@ -228,35 +266,43 @@ class InvenTreeAPI {
     _version = data["version"];
 
     if (!_checkServerVersion(_version)) {
-      // TODO - Something?
+      await showServerError(context, "Server version is too old.\n\nServer Version: ${_version}\n\nRequired version: ${_requiredVersionString}");
+      return false;
     }
 
     // Record the instance name of the server
     instance = data['instance'] ?? '';
 
     // Request token from the server if we do not already have one
-    if (_token.isNotEmpty) {
+    if (false && _token.isNotEmpty) {
       print("Already have token - $_token");
       return true;
     }
 
-    // Clear out the token
+    // Clear the existing token value
     _token = "";
 
+    print("Requesting token from server");
+
     response = await get(_URL_GET_TOKEN).timeout(Duration(seconds: 10)).catchError((error) {
       print("Error requesting token:");
       print(error);
-      return false;
+      return null;
     });
 
+    if (response == null) {
+      await showServerError(context, "Error requesting access token");
+      return false;
+    }
+
     if (response.statusCode != 200) {
-      print("Invalid status code: " + response.statusCode.toString());
+      await showServerError(context, "Invalid status code: ${response.statusCode.toString()}");
       return false;
     } else {
       var data = json.decode(response.body);
 
       if (!data.containsKey("token")) {
-        print("No token provided in response");
+        await showServerError(context, "No token provided in response");
         return false;
       }
 

lib/barcode.dart

@@ -32,7 +32,6 @@ class BarcodeHandler {
     QRViewController _controller;
     BuildContext _context;
 
-
     Future<void> onBarcodeMatched(Map<String, dynamic> data) {
       // Called when the server "matches" a barcode
       // Override this function

lib/l10n

@@ -1 +1 @@
-Subproject commit 6b50ee704cacfb3d9b45d89de31b1ce05e94959a
+Subproject commit 8f8809c18776e8bfac050c35ad17e0416af96ad4

lib/main.dart

@@ -45,9 +45,6 @@ void main() async {
 
   WidgetsFlutterBinding.ensureInitialized();
 
-  // Load login details
-  InvenTreePreferences().loadLoginDetails();
-
   runZoned<Future<void>>(() async {
     runApp(InvenTreeApp());
   }, onError: (error, stackTrace) {
@@ -63,6 +60,7 @@ class InvenTreeApp extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+
     return MaterialApp(
       onGenerateTitle: (BuildContext context) => I18N.of(context).appTitle,
       theme: ThemeData(

lib/preferences.dart

@@ -1,3 +1,4 @@
+import 'package:flutter/cupertino.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'api.dart';
 
@@ -35,7 +36,7 @@ class InvenTreePreferences {
   InvenTreePreferences._internal();
 
   // Load saved login details, and attempt connection
-  void loadLoginDetails() async {
+  void loadLoginDetails(BuildContext context) async {
 
     print("Loading login details");
 
@@ -45,10 +46,10 @@ class InvenTreePreferences {
     var username = prefs.getString(_USERNAME) ?? '';
     var password = prefs.getString(_PASSWORD) ?? '';
 
-    await InvenTreeAPI().connectToServer(server, username, password);
+    await InvenTreeAPI().connectToServer(context, server, username, password);
   }
 
-  void saveLoginDetails(String server, String username, String password) async {
+  void saveLoginDetails(BuildContext context, String server, String username, String password) async {
 
     SharedPreferences prefs = await SharedPreferences.getInstance();
 
@@ -57,6 +58,6 @@ class InvenTreePreferences {
     await prefs.setString(_PASSWORD, password);
 
     // Reconnect the API
-    await InvenTreeAPI().connectToServer(server, username, password);
+    await InvenTreeAPI().connectToServer(context, server, username, password);
   }
 }

lib/settings/login.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:shared_preferences/shared_preferences.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 
 import '../api.dart';
 import '../preferences.dart';
@@ -61,6 +62,15 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
     return null;
   }
 
+  void _save(BuildContext context) async {
+    if (_formKey.currentState.validate()) {
+      _formKey.currentState.save();
+
+      await InvenTreePreferences().saveLoginDetails(context, _server, _username, _password);
+
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
 
@@ -76,7 +86,7 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
           key: _formKey,
           child: new ListView(
             children: <Widget>[
-              Text("Server Address"),
+              Text(I18N.of(context).serverAddress),
               new TextFormField(
                 initialValue: _server,
                 decoration: InputDecoration(
@@ -92,8 +102,8 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
               TextFormField(
                 initialValue: _username,
                 decoration: InputDecoration(
-                  hintText: "Username",
+                  hintText: I18N.of(context).username,
-                  labelText: "Username",
+                  labelText: I18N.of(context).username,
                 ),
                 validator: _validateUsername,
                 onSaved: (String value) {
@@ -104,8 +114,8 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
                 initialValue: _password,
                 obscureText: true,
                 decoration: InputDecoration(
-                  hintText: "Password",
+                  hintText: I18N.of(context).password,
-                  labelText: "Password",
+                  labelText: I18N.of(context).password,
                 ),
                 validator: _validatePassword,
                 onSaved: (String value) {
@@ -115,8 +125,10 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
               Container(
                 width: screenSize.width,
                 child: RaisedButton(
-                  child: Text("Save"),
+                  child: Text(I18N.of(context).save),
-                  onPressed: this.save,
+                  onPressed: () {
+                    _save(context);
+                  }
                 )
               )
             ],
@@ -125,13 +137,4 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
       )
     );
   }
-
-  void save() async {
-    if (_formKey.currentState.validate()) {
-      _formKey.currentState.save();
-
-      await InvenTreePreferences().saveLoginDetails(_server, _username, _password);
-
-    }
-  }
 }

lib/widget/dialogs.dart

@@ -2,6 +2,7 @@
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 
 void showMessage(BuildContext context, String message) {
   Scaffold.of(context).showSnackBar(SnackBar(
@@ -9,7 +10,12 @@ void showMessage(BuildContext context, String message) {
   ));
 }
 
-Future<void> showInfoDialog(BuildContext context, String title, String description, {IconData icon = FontAwesomeIcons.info, String info = "Info", Function onDismissed}) async {
+Future<void> showInfoDialog(BuildContext context, String title, String description, {IconData icon = FontAwesomeIcons.info, String info, Function onDismissed}) async {
+
+  if (info == null || info.isEmpty) {
+    info = I18N.of(context).info;
+  }
+
   showDialog(
     context: context,
     child: SimpleDialog(
@@ -31,7 +37,12 @@ Future<void> showInfoDialog(BuildContext context, String title, String descripti
   });
 }
 
-Future<void> showErrorDialog(BuildContext context, String title, String description, {IconData icon = FontAwesomeIcons.exclamationCircle, String error = "Error", Function onDismissed}) async {
+Future<void> showErrorDialog(BuildContext context, String title, String description, {IconData icon = FontAwesomeIcons.exclamationCircle, String error, Function onDismissed}) async {
+
+  if (error == null || error.isEmpty) {
+    error = I18N.of(context).error;
+  }
+
   showDialog(
     context: context,
     child: SimpleDialog(

lib/widget/home.dart

@@ -25,7 +25,6 @@ class InvenTreeHomePage extends StatefulWidget {
 class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
 
   _InvenTreeHomePageState() : super() {
-    _checkServerConnection();
   }
 
   String _serverAddress = "";
@@ -63,7 +62,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
   /*
    * Test the server connection
    */
-  void _checkServerConnection() async {
+  void _checkServerConnection(BuildContext context) async {
 
     var prefs = await SharedPreferences.getInstance();
 
@@ -76,7 +75,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
     _serverIcon = new FaIcon(FontAwesomeIcons.spinner);
     _serverStatusColor = Color.fromARGB(255, 50, 50, 250);
 
-    InvenTreeAPI().connect().then((bool result) {
+    InvenTreeAPI().connect(context).then((bool result) {
 
       if (result) {
         onConnectSuccess("");
@@ -322,7 +321,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
                     leading: _serverIcon,
                     onTap: () {
                       if (!_serverConnection) {
-                        _checkServerConnection();
+                        _checkServerConnection(context);
                       }
                     },
                   ),