Windows image loader error handling (#260)

* Repros for various image issues

* Log image loading errors

* Better repro instructions and user interface

* Image loading tests now running on WinRT/UWP phone/tablet/desktop

* Move FailImageSource into shared project

* Move FailImageSource into shared project

* Update docs

8 files changed, 47 insertions, 22 deletions

diff --git a/Xamarin.Forms.Platform.WinRT/FileImageSourceHandler.cs b/Xamarin.Forms.Platform.WinRT/FileImageSourceHandler.cs
index c9c6f16b..2e1a907a 100644
--- a/Xamarin.Forms.Platform.WinRT/FileImageSourceHandler.cs
+++ b/Xamarin.Forms.Platform.WinRT/FileImageSourceHandler.cs
@@ -13,10 +13,10 @@ namespace Xamarin.Forms.Platform.WinRT
 {
 	public sealed class FileImageSourceHandler : IImageSourceHandler
 	{
-		public Task<Windows.UI.Xaml.Media.ImageSource> LoadImageAsync(ImageSource imagesoure, CancellationToken cancellationToken = new CancellationToken())
+		public Task<Windows.UI.Xaml.Media.ImageSource> LoadImageAsync(ImageSource imagesource, CancellationToken cancellationToken = new CancellationToken())
 		{
 			Windows.UI.Xaml.Media.ImageSource image = null;
-			var filesource = imagesoure as FileImageSource;
+			var filesource = imagesource as FileImageSource;
 			if (filesource != null)
 			{
 				string file = filesource.File;
diff --git a/Xamarin.Forms.Platform.WinRT/IImageSourceHandler.cs b/Xamarin.Forms.Platform.WinRT/IImageSourceHandler.cs
index 91eff534..457d48e4 100644
--- a/Xamarin.Forms.Platform.WinRT/IImageSourceHandler.cs
+++ b/Xamarin.Forms.Platform.WinRT/IImageSourceHandler.cs
@@ -11,6 +11,6 @@ namespace Xamarin.Forms.Platform.WinRT
 {
 	public interface IImageSourceHandler : IRegisterable
 	{
-		Task<Windows.UI.Xaml.Media.ImageSource> LoadImageAsync(ImageSource imagesoure, CancellationToken cancellationToken = default(CancellationToken));
+		Task<Windows.UI.Xaml.Media.ImageSource> LoadImageAsync(ImageSource imagesource, CancellationToken cancellationToken = default(CancellationToken));
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs b/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs
index 370da329..fa676c18 100644
--- a/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs
@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel;
+using System.Threading.Tasks;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Media;
 using Windows.UI.Xaml.Media.Imaging;
@@ -34,12 +35,13 @@ namespace Xamarin.Forms.Platform.WinRT
 			if (Control != null)
 			{
 				Control.ImageOpened -= OnImageOpened;
+				Control.ImageFailed -= OnImageFailed;
 			}
 
 			base.Dispose(disposing);
 		}
 
-		protected override void OnElementChanged(ElementChangedEventArgs<Image> e)
+		protected override async void OnElementChanged(ElementChangedEventArgs<Image> e)
 		{
 			base.OnElementChanged(e);
 
@@ -49,20 +51,21 @@ namespace Xamarin.Forms.Platform.WinRT
 				{
 					var image = new Windows.UI.Xaml.Controls.Image();
 					image.ImageOpened += OnImageOpened;
+					image.ImageFailed += OnImageFailed;
 					SetNativeControl(image);
 				}
 
-				UpdateSource();
+				await UpdateSource();
 				UpdateAspect();
 			}
 		}
 
-		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
+		protected override async void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
 		{
 			base.OnElementPropertyChanged(sender, e);
 
 			if (e.PropertyName == Image.SourceProperty.PropertyName)
-				UpdateSource();
+				await UpdateSource();
 			else if (e.PropertyName == Image.AspectProperty.PropertyName)
 				UpdateAspect();
 		}
@@ -87,6 +90,14 @@ namespace Xamarin.Forms.Platform.WinRT
 			{
 				RefreshImage();
 			}
+
+			((IImageController)Element)?.SetIsLoading(false);
+		}
+
+		void OnImageFailed(object sender, ExceptionRoutedEventArgs exceptionRoutedEventArgs)
+		{
+			Log.Warning("Image Loading", $"Image failed to load: {exceptionRoutedEventArgs.ErrorMessage}" );
+			((IImageController)Element)?.SetIsLoading(false);
 		}
 
 		void RefreshImage()
@@ -109,7 +120,7 @@ namespace Xamarin.Forms.Platform.WinRT
 			}
 		}
 
-		async void UpdateSource()
+		async Task UpdateSource()
 		{
 			((IImageController)Element).SetIsLoading(true);
 
@@ -117,7 +128,8 @@ namespace Xamarin.Forms.Platform.WinRT
 			IImageSourceHandler handler;
 			if (source != null && (handler = Registrar.Registered.GetHandler<IImageSourceHandler>(source.GetType())) != null)
 			{
-				Windows.UI.Xaml.Media.ImageSource imagesource;
+				Windows.UI.Xaml.Media.ImageSource imagesource = null;
+
 				try
 				{
 					imagesource = await handler.LoadImageAsync(source);
@@ -126,18 +138,25 @@ namespace Xamarin.Forms.Platform.WinRT
 				{
 					imagesource = null;
 				}
+				catch (Exception ex)
+				{
+					Log.Warning("Image Loading", $"Error updating image source: {ex}");
+				}
 
 				// In the time it takes to await the imagesource, some zippy little app
 				// might have disposed of this Image already.
 				if (Control != null)
+				{
 					Control.Source = imagesource;
+				}
 
 				RefreshImage();
 			}
 			else
+			{
 				Control.Source = null;
-
-			((IImageController)Element)?.SetIsLoading(false);
+				((IImageController)Element)?.SetIsLoading(false);
+			}
 		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.WinRT/Properties/AssemblyInfo.cs b/Xamarin.Forms.Platform.WinRT/Properties/AssemblyInfo.cs
index d1975076..83023289 100644
--- a/Xamarin.Forms.Platform.WinRT/Properties/AssemblyInfo.cs
+++ b/Xamarin.Forms.Platform.WinRT/Properties/AssemblyInfo.cs
@@ -37,8 +37,8 @@ using Xamarin.Forms.Platform.WinRT;
 //ImageSources
 
 [assembly: ExportImageSourceHandler(typeof(FileImageSource), typeof(FileImageSourceHandler))]
-[assembly: ExportImageSourceHandler(typeof(StreamImageSource), typeof(StreamImagesourceHandler))]
-[assembly: ExportImageSourceHandler(typeof(UriImageSource), typeof(ImageLoaderSourceHandler))]
+[assembly: ExportImageSourceHandler(typeof(StreamImageSource), typeof(StreamImageSourceHandler))]
+[assembly: ExportImageSourceHandler(typeof(UriImageSource), typeof(UriImageSourceHandler))]
 
 // Pages
 
diff --git a/Xamarin.Forms.Platform.WinRT/StreamImagesourceHandler.cs b/Xamarin.Forms.Platform.WinRT/StreamImagesourceHandler.cs
index 20d2c504..da2b1ff0 100644
--- a/Xamarin.Forms.Platform.WinRT/StreamImagesourceHandler.cs
+++ b/Xamarin.Forms.Platform.WinRT/StreamImagesourceHandler.cs
@@ -12,7 +12,7 @@ namespace Xamarin.Forms.Platform.UWP
 namespace Xamarin.Forms.Platform.WinRT
 #endif 
 {
-	public sealed class StreamImagesourceHandler : IImageSourceHandler
+	public sealed class StreamImageSourceHandler : IImageSourceHandler
 	{
 		public async Task<Windows.UI.Xaml.Media.ImageSource> LoadImageAsync(ImageSource imagesource, CancellationToken cancellationToken = new CancellationToken())
 		{
diff --git a/Xamarin.Forms.Platform.WinRT/ImageLoaderSourceHandler.cs b/Xamarin.Forms.Platform.WinRT/UriImageSourceHandler.cs
index d2b223b5..1263c355 100644
--- a/Xamarin.Forms.Platform.WinRT/ImageLoaderSourceHandler.cs
+++ b/Xamarin.Forms.Platform.WinRT/UriImageSourceHandler.cs
@@ -14,11 +14,11 @@ namespace Xamarin.Forms.Platform.UWP
 namespace Xamarin.Forms.Platform.WinRT
 #endif
 {
-	public sealed class ImageLoaderSourceHandler : IImageSourceHandler
+	public sealed class UriImageSourceHandler : IImageSourceHandler
 	{
-		public async Task<Windows.UI.Xaml.Media.ImageSource> LoadImageAsync(ImageSource imagesoure, CancellationToken cancellationToken = new CancellationToken())
+		public async Task<Windows.UI.Xaml.Media.ImageSource> LoadImageAsync(ImageSource imagesource, CancellationToken cancellationToken = new CancellationToken())
 		{
-			var imageLoader = imagesoure as UriImageSource;
+			var imageLoader = imagesource as UriImageSource;
 			if (imageLoader?.Uri == null)
 				return null;
 
@@ -36,11 +36,10 @@ namespace Xamarin.Forms.Platform.WinRT
 					await image.SetSourceAsync(stream);
 					return image;
 				}
-				catch (Exception ex)
+				catch (Exception ex) 
 				{
-					Debug.WriteLine(ex);
+					Log.Warning("Image Loading", $"{nameof(UriImageSourceHandler)} could not load {imageLoader.Uri}: {ex}");
 
-					// Because this literally throws System.Exception
 					// According to https://msdn.microsoft.com/library/windows/apps/jj191522
 					// this can happen if the image data is bad or the app is close to its 
 					// memory limit
diff --git a/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs b/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs
index 603ec401..49589a8a 100644
--- a/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs
+++ b/Xamarin.Forms.Platform.WinRT/WindowsBasePlatformServices.cs
@@ -99,7 +99,14 @@ namespace Xamarin.Forms.Platform.WinRT
 			using (var client = new HttpClient())
 			{
 				HttpResponseMessage streamResponse = await client.GetAsync(uri.AbsoluteUri).ConfigureAwait(false);
-				return streamResponse.IsSuccessStatusCode ? await streamResponse.Content.ReadAsStreamAsync().ConfigureAwait(false) : null;
+
+				if (!streamResponse.IsSuccessStatusCode)
+				{
+					Log.Warning("HTTP Request", $"Could not retrieve {uri}, status code {streamResponse.StatusCode}");
+					return null;
+				}
+
+				return await streamResponse.Content.ReadAsStreamAsync().ConfigureAwait(false);
 			}
 		}
 
diff --git a/Xamarin.Forms.Platform.WinRT/Xamarin.Forms.Platform.WinRT.csproj b/Xamarin.Forms.Platform.WinRT/Xamarin.Forms.Platform.WinRT.csproj
index 6d28b900..f6b3566a 100644
--- a/Xamarin.Forms.Platform.WinRT/Xamarin.Forms.Platform.WinRT.csproj
+++ b/Xamarin.Forms.Platform.WinRT/Xamarin.Forms.Platform.WinRT.csproj
@@ -125,7 +125,7 @@
     <Compile Include="HeightConverter.cs" />
     <Compile Include="ICellRenderer.cs" />
     <Compile Include="IImageSourceHandler.cs" />
-    <Compile Include="ImageLoaderSourceHandler.cs" />
+    <Compile Include="UriImageSourceHandler.cs" />
     <Compile Include="ImageRenderer.cs" />
     <Compile Include="IVisualElementRenderer.cs" />
     <Compile Include="LabelRenderer.cs" />