WP8 Some images not downloading using HttpClient - windows-phone-8

Question

I am building a WP8 app that downloads images using HttpClient in a background task. My problem is that some images are not downloaded no matter how much time I wait for them to finish. The image sizes are a few megabytes at maximum.
The code I use to download images:
internal static async Task<bool> Download_Wallpaper(string image_url, string file_name, string destination_folder_name)
{
try
{
using (var client = new HttpClient())
{
// 12MB max images
client.Timeout = TimeSpan.FromSeconds(5);
client.MaxResponseContentBufferSize = DeviceStatus.ApplicationMemoryUsageLimit / 2;
//client.Timeout = TimeSpan.FromSeconds(5);
byte[] image_byte_arr;
try
{
/* var requestMessage = new HttpRequestMessage( HttpMethod.Get, image_url );
var responseMessage = await client.SendAsync((requestMessage));
// byte array of image
image_byte_arr = await responseMessage.Content.ReadAsByteArrayAsync();
*/
// byte array of image
image_byte_arr = await client.GetByteArrayAsync(image_url);
}
// Could not download
catch (OutOfMemoryException X)
{
GC.Collect();
return false;
}
var folder = await StorageFolder.GetFolderFromPathAsync(destination_folder_name);
// Create file
StorageFile file = await folder.CreateFileAsync(file_name, CreationCollisionOption.ReplaceExisting);
using (var write_stream = await file.OpenStreamForWriteAsync())
{
write_stream.Write(image_byte_arr, 0, image_byte_arr.Length);
}
Console.WriteLine(DeviceStatus.ApplicationCurrentMemoryUsage);
return true;
}
}
catch (HttpRequestException X)
{
Console.WriteLine(X);
return false;
}
catch (OutOfMemoryException X)
{
GC.Collect();
return false;
}
catch (Exception X)
{
Console.WriteLine(X);
return false;
}
}
This is an example image that fails to download: https://upload.wikimedia.org/wikipedia/commons/9/95/Tracy_Caldwell_Dyson_in_Cupola_ISS.jpg
In my experience all wikimedia images fail to download for some reason.
I see no way of tracking download progress using HttpClient. Is there a way to do so?
Edit: It seems that setting the timeout does not have any function. The HttpRequestException is not thrown after 5 seconds.
Edit2: I tried a different approach, the one that anonshankar suggested. With that method the code would get stuck at the line:
byte[] img = response.Content.ReadAsByteArrayAsync();
So the HttpResponse arrives, but somehow the bytes could not be read out, no matter how much time I gave it. How could this even happen? The hard part is getting the response, reading out the bytes should be simple.
Again, this only happens with some images, most of them downloads correctly. One example is mentioned above.
I have modified my image downloader code, so that it times out after a few seconds. Here is my final code:
internal static async Task<bool> Download_Wallpaper(string image_url, string file_name, string destination_folder_name)
{
try
{
using (var client = new HttpClient())
{
// prevent running out of memory
client.MaxResponseContentBufferSize = DeviceStatus.ApplicationMemoryUsageLimit / 3;
byte[] image_byte_arr = null;
using (CancellationTokenSource cts = new CancellationTokenSource())
{
var task = Task.Factory.StartNew(() =>
{
try
{
image_byte_arr = client.GetByteArrayAsync(image_url).Result;
}
catch (AggregateException X)// Handling read errors, usually image is too big
{
Console.WriteLine(X.Message);
foreach (var v in X.InnerExceptions)
Console.WriteLine(v.Message);
image_byte_arr = null;
}
}, cts.Token);
bool finished_in_time = task.Wait(TimeSpan.FromSeconds(5));
if (!finished_in_time)// Timeout
{
cts.Cancel();
task.Wait();
return false;
}
else if (image_byte_arr == null)// Read error
{
return false;
}
}
var folder = await StorageFolder.GetFolderFromPathAsync(destination_folder_name);
// Create file
StorageFile file = await folder.CreateFileAsync(file_name, CreationCollisionOption.ReplaceExisting);
using (var write_stream = await file.OpenStreamForWriteAsync())
{
write_stream.Write(image_byte_arr, 0, image_byte_arr.Length);
}
Console.WriteLine(DeviceStatus.ApplicationCurrentMemoryUsage);
return true;
}
}
catch (HttpRequestException X)
{
Console.WriteLine(X);
return false;
}
catch (OutOfMemoryException X)
{
GC.Collect();
return false;
}
catch (Exception X)
{
Console.WriteLine(X);
return false;
}
}
Any improvement suggestions are welcome, and I still don't understand why does the method HttpContent.ReadAsByteArrayAsync() gets stuck.

Answer 1

Just try out this snippet which worked for me.
HttpClient client = new HttpClient();
HttpResponseMessage response = await client.GetAsync("give the url");
byte[] img = response.Content.ReadAsByteArray();
InMemoryRandomAccessStream randomAccessStream = new InMemoryRandomAccessStream();
DataWriter writer = new DataWriter(randomAccessStream.GetOutputStreamAt(0));
writer.WriteBytes(img);
await writer.StoreAsync();
BitmapImage b = new BitmapImage();
b.SetSource(randomAccessStream);
pic.Source = b; //(pic is an `<Image>` defined in the `XAML`
Hope it helps!