Add some error handling

DiscordChatExporter/Container.cs

@@ -12,13 +12,14 @@ namespace DiscordChatExporter
             ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
 
             // Services
-            SimpleIoc.Default.Register<IDataService, DataService>();
+            SimpleIoc.Default.Register<IDataService, DataService>(true);
-            SimpleIoc.Default.Register<IExportService, ExportService>();
+            SimpleIoc.Default.Register<IExportService, ExportService>(true);
-            SimpleIoc.Default.Register<ISettingsService, SettingsService>();
+            SimpleIoc.Default.Register<ISettingsService, SettingsService>(true);
 
             // View models
-            SimpleIoc.Default.Register<IMainViewModel, MainViewModel>();
+            SimpleIoc.Default.Register<IErrorViewModel, ErrorViewModel>(true);
-            SimpleIoc.Default.Register<ISettingsViewModel, SettingsViewModel>();
+            SimpleIoc.Default.Register<IMainViewModel, MainViewModel>(true);
+            SimpleIoc.Default.Register<ISettingsViewModel, SettingsViewModel>(true);
 
             // Load settings
             ServiceLocator.Current.GetInstance<ISettingsService>().Load();
@@ -30,6 +31,7 @@ namespace DiscordChatExporter
             ServiceLocator.Current.GetInstance<ISettingsService>().Save();
         }
 
+        public IErrorViewModel ErrorViewModel => ServiceLocator.Current.GetInstance<IErrorViewModel>();
         public IMainViewModel MainViewModel => ServiceLocator.Current.GetInstance<IMainViewModel>();
         public ISettingsViewModel SettingsViewModel => ServiceLocator.Current.GetInstance<ISettingsViewModel>();
     }

DiscordChatExporter/DiscordChatExporter.csproj

@@ -84,12 +84,19 @@
     <Reference Include="PresentationFramework" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Exceptions\UnathorizedException.cs" />
+    <Compile Include="Messages\ShowErrorMessage.cs" />
     <Compile Include="Messages\ShowSettingsMessage.cs" />
     <Compile Include="Models\AttachmentType.cs" />
     <Compile Include="Models\ChannelChatLog.cs" />
     <Compile Include="Models\ChannelType.cs" />
+    <Compile Include="ViewModels\ErrorViewModel.cs" />
+    <Compile Include="ViewModels\IErrorViewModel.cs" />
     <Compile Include="ViewModels\ISettingsViewModel.cs" />
     <Compile Include="ViewModels\SettingsViewModel.cs" />
+    <Compile Include="Views\ErrorDialog.ammy.cs">
+      <DependentUpon>ErrorDialog.ammy</DependentUpon>
+    </Compile>
     <Compile Include="Views\SettingsDialog.ammy.cs">
       <DependentUpon>SettingsDialog.ammy</DependentUpon>
     </Compile>
@@ -98,6 +105,11 @@
       <Generator>XamlIntelliSenseFileGenerator</Generator>
       <DependentUpon>App.ammy</DependentUpon>
     </Page>
+    <Page Include="Views\ErrorDialog.g.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+      <DependentUpon>ErrorDialog.ammy</DependentUpon>
+    </Page>
     <Page Include="Views\MainWindow.g.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
@@ -150,6 +162,7 @@
     <None Include="packages.config">
       <SubType>Designer</SubType>
     </None>
+    <None Include="Views\ErrorDialog.ammy" />
     <None Include="Views\MainWindow.ammy" />
     <None Include="Views\SettingsDialog.ammy" />
   </ItemGroup>

DiscordChatExporter/Exceptions/UnathorizedException.cs

@@ -0,0 +1,8 @@
+using System;
+
+namespace DiscordChatExporter.Exceptions
+{
+    public class UnathorizedException : Exception
+    {
+    }
+}

DiscordChatExporter/Messages/ShowErrorMessage.cs

@@ -0,0 +1,12 @@
+namespace DiscordChatExporter.Messages
+{
+    public class ShowErrorMessage
+    {
+        public string Message { get; }
+
+        public ShowErrorMessage(string message)
+        {
+            Message = message;
+        }
+    }
+}

DiscordChatExporter/Services/DataService.cs

@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net;
 using System.Net.Http;
 using System.Threading.Tasks;
+using DiscordChatExporter.Exceptions;
 using DiscordChatExporter.Models;
 using Newtonsoft.Json.Linq;
 using Tyrrrz.Extensions;
@@ -14,16 +16,30 @@ namespace DiscordChatExporter.Services
         private const string ApiRoot = "https://discordapp.com/api/v6";
         private readonly HttpClient _httpClient = new HttpClient();
 
+        private async Task<string> GetStringAsync(string url)
+        {
+            using (var response = await _httpClient.GetAsync(url))
+            {
+                // Check status code
+                if (response.StatusCode.IsEither(HttpStatusCode.Unauthorized, HttpStatusCode.Forbidden))
+                    throw new UnathorizedException();
+                response.EnsureSuccessStatusCode();
+
+                // Get content
+                return await response.Content.ReadAsStringAsync();
+            }
+        }
+
         public async Task<IEnumerable<Guild>> GetGuildsAsync(string token)
         {
             // Form request url
             var url = $"{ApiRoot}/users/@me/guilds?token={token}&limit=100";
 
             // Get response
-            var response = await _httpClient.GetStringAsync(url);
+            var content = await GetStringAsync(url);
 
             // Parse
-            var guilds = JArray.Parse(response).Select(ParseGuild);
+            var guilds = JArray.Parse(content).Select(ParseGuild);
 
             return guilds;
         }
@@ -34,10 +50,10 @@ namespace DiscordChatExporter.Services
             var url = $"{ApiRoot}/users/@me/channels?token={token}";
 
             // Get response
-            var response = await _httpClient.GetStringAsync(url);
+            var content = await GetStringAsync(url);
 
             // Parse
-            var channels = JArray.Parse(response).Select(ParseChannel);
+            var channels = JArray.Parse(content).Select(ParseChannel);
 
             return channels;
         }
@@ -48,10 +64,10 @@ namespace DiscordChatExporter.Services
             var url = $"{ApiRoot}/guilds/{guildId}/channels?token={token}";
 
             // Get response
-            var response = await _httpClient.GetStringAsync(url);
+            var content = await GetStringAsync(url);
 
             // Parse
-            var channels = JArray.Parse(response).Select(ParseChannel);
+            var channels = JArray.Parse(content).Select(ParseChannel);
 
             return channels;
         }
@@ -71,10 +87,10 @@ namespace DiscordChatExporter.Services
                     url += $"&before={beforeId}";
 
                 // Get response
-                var response = await _httpClient.GetStringAsync(url);
+                var content = await GetStringAsync(url);
 
                 // Parse
-                var messages = JArray.Parse(response).Select(ParseMessage);
+                var messages = JArray.Parse(content).Select(ParseMessage);
 
                 // Add messages to list
                 string currentMessageId = null;

DiscordChatExporter/ViewModels/ErrorViewModel.cs

@@ -0,0 +1,15 @@
+using DiscordChatExporter.Messages;
+using GalaSoft.MvvmLight;
+
+namespace DiscordChatExporter.ViewModels
+{
+    public class ErrorViewModel : ViewModelBase, IErrorViewModel
+    {
+        public string Message { get; private set; }
+
+        public ErrorViewModel()
+        {
+            MessengerInstance.Register<ShowErrorMessage>(this, m => Message = m.Message);
+        }
+    }
+}

DiscordChatExporter/ViewModels/IErrorViewModel.cs

@@ -0,0 +1,7 @@
+namespace DiscordChatExporter.ViewModels
+{
+    public interface IErrorViewModel
+    {
+        string Message { get; }
+    }
+}

DiscordChatExporter/ViewModels/MainViewModel.cs

@@ -2,6 +2,7 @@
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
+using DiscordChatExporter.Exceptions;
 using DiscordChatExporter.Messages;
 using DiscordChatExporter.Models;
 using DiscordChatExporter.Services;
@@ -107,6 +108,8 @@ namespace DiscordChatExporter.ViewModels
             // Clear existing
             _guildChannelsMap.Clear();
 
+            try
+            {
                 // Get DM channels
                 {
                     var channels = await _dataService.GetDirectMessageChannelsAsync(_cachedToken);
@@ -124,6 +127,11 @@ namespace DiscordChatExporter.ViewModels
                         _guildChannelsMap[guild] = channels.ToArray();
                     }
                 }
+            }
+            catch (UnathorizedException)
+            {
+                MessengerInstance.Send(new ShowErrorMessage("Failed to authorize. Make sure the token is valid."));
+            }
 
             AvailableGuilds = _guildChannelsMap.Keys.ToArray();
             SelectedGuild = AvailableGuilds.FirstOrDefault();
@@ -135,13 +143,13 @@ namespace DiscordChatExporter.ViewModels
             IsBusy = true;
             
             // Get safe file names
-            var safeGroupName = SelectedGuild.Name.Replace(Path.GetInvalidFileNameChars(), '_');
+            var safeGuildName = SelectedGuild.Name.Replace(Path.GetInvalidFileNameChars(), '_');
             var safeChannelName = channel.Name.Replace(Path.GetInvalidFileNameChars(), '_');
 
             // Ask for path
             var sfd = new SaveFileDialog
             {
-                FileName = $"{safeGroupName} - {safeChannelName}.html",
+                FileName = $"{safeGuildName} - {safeChannelName}.html",
                 Filter = "HTML files (*.html)|*.html|All files (*.*)|*.*",
                 DefaultExt = "html",
                 AddExtension = true
@@ -152,6 +160,9 @@ namespace DiscordChatExporter.ViewModels
                 return;
             }
 
+            // Export
+            try
+            {
                 // Get messages
                 var messages = await _dataService.GetChannelMessagesAsync(_cachedToken, channel.Id);
 
@@ -160,6 +171,11 @@ namespace DiscordChatExporter.ViewModels
 
                 // Export
                 _exportService.Export(sfd.FileName, chatLog, _settingsService.Theme);
+            }
+            catch (UnathorizedException)
+            {
+                MessengerInstance.Send(new ShowErrorMessage("Failed to export. You don't have access to that channel."));
+            }
 
             IsBusy = false;
         }

DiscordChatExporter/Views/ErrorDialog.ammy

@@ -0,0 +1,25 @@
+using MaterialDesignThemes.Wpf
+
+UserControl "DiscordChatExporter.Views.ErrorDialog" {
+  DataContext: bind ErrorViewModel from $resource Container
+    Width: 250
+
+    StackPanel {
+      // Message
+      TextBlock {
+        Margin: 8
+        FontSize: 16
+        HorizontalAlignment: Center
+        TextWrapping: WrapWithOverflow
+        Text: bind Message
+      }
+
+      // OK
+      Button {
+        Command: DialogHost.CloseDialogCommand
+        Content: "OK"
+        Margin: 8
+        Style: resource dyn "MaterialDesignFlatButton"
+      }
+    }
+}

DiscordChatExporter/Views/ErrorDialog.ammy.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DiscordChatExporter.Views
+{
+    public partial class ErrorDialog
+    {
+        public ErrorDialog()
+        {
+            InitializeComponent();
+        }
+    }
+}

DiscordChatExporter/Views/MainWindow.ammy.cs

@@ -17,6 +17,7 @@ namespace DiscordChatExporter.Views
             InitializeComponent();
             Title += $" v{Assembly.GetExecutingAssembly().GetName().Version}";
 
+            Messenger.Default.Register<ShowErrorMessage>(this, m => DialogHost.Show(new ErrorDialog()).Forget());
             Messenger.Default.Register<ShowSettingsMessage>(this, m => DialogHost.Show(new SettingsDialog()).Forget());
         }