/// <summary>
/// Helper method to POST binary image data to an API endpoint that expects the data to be accompanied by a parameter
/// </summary>
/// <param name="client">HttpClient instance</param>
/// <param name="imageFile">Valie StorageFile of the image</param>
/// <param name="url">The API's http or https endpoint</param>
/// <param name="progessReporter">Progress reporter to track progress of the download operation</param>
/// <param name="parameterName">The name of the parameter the API expects the image data in</param>
/// <returns></returns>
public static async Task<string> SendImageDataWithDownloadProgressAsync(this HttpClient client, StorageFile imageFile, string url, string parameterName, IProgress<DownloadProgressArgs> progessReporter)
{
if (client == null)
throw new ArgumentNullException(nameof(client), "HttpClient was null");
if (string.IsNullOrEmpty(url))
throw new ArgumentNullException(nameof(url), "You must set a URL for the the HttpClient");
if (imageFile == null)
throw new ArgumentNullException(nameof(imageFile), "You must have a valid StorageFile for this method to work");
if (string.IsNullOrEmpty(parameterName))
throw new ArgumentNullException(nameof(parameterName), "You must set a parameter name for the image data");
if (progessReporter == null)
throw new ArgumentNullException(nameof(progessReporter), "ProgressReporter was null");
try
{
client.DefaultRequestHeaders.ExpectContinue = false;
byte[] fileBytes;
using (var fileStream = await imageFile.OpenStreamForReadAsync())
{
var binaryReader = new BinaryReader(fileStream);
fileBytes = binaryReader.ReadBytes((int) fileStream.Length);
}
var multipartContent = new MultipartFormDataContent();
multipartContent.Add(new ByteArrayContent(fileBytes), parameterName);
using (var response = await client.PostAsync(new Uri(url), multipartContent))
using (var stream = await response.Content.ReadAsStreamAsync())
using (var memStream = new MemoryStream())
{
int receivedBytes = 0;
var totalBytes = Convert.ToInt32(response.Content.Headers.ContentLength);
while (true)
{
var buffer = new byte[4096];
int bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);
//write the current loop's bytes into the MemoryStream that will be returned
await memStream.WriteAsync(buffer, 0, bytesRead);
if (bytesRead == 0)
{
break;
}
receivedBytes += bytesRead;
var args = new DownloadProgressArgs(receivedBytes, receivedBytes);
progessReporter.Report(args);
Debug.WriteLine($"Progress: {receivedBytes} of {totalBytes} bytes read");
}
memStream.Position = 0;
var stringContent = new StreamReader(memStream);
return stringContent.ReadToEnd();
}
}
finally
{
client.Dispose();
}
}
//This is the event handler to update your UI of progress (there is no need to use UI Dispatcher)
private void Reporter_ProgressChanged(object sender, DownloadProgressArgs e)
{
DownloadProgress = e.PercentComplete;
IsBusyMessage = $"downloading {e.PercentComplete.ToString("N2")}%";
}
/// <summary>
/// Stand-in replacement for HttpClient.GetStringAsync that can report download progress.
/// </summary>
/// <param name="client">HttpClient instance</param>
/// <param name="url">Url of where to download the stream from</param>
/// <param name="progessReporter">Progress reporter to track progress of the download operation</param>
/// <returns>String result of the GET request</returns>
public static async Task<string> DownloadStringWithProgressAsync(this HttpClient client, string url, IProgress<DownloadProgressArgs> progessReporter)
{
if (client == null)
throw new ArgumentNullException(nameof(client), "HttpClient was null");
if (string.IsNullOrEmpty(url))
throw new ArgumentNullException(nameof(url), "You must set a URL for the API endpoint");
if (progessReporter == null)
throw new ArgumentNullException(nameof(progessReporter), "ProgressReporter was null");
try
{
client.DefaultRequestHeaders.ExpectContinue = false;
using (var response = await client.GetAsync(url, HttpCompletionOption.ResponseHeadersRead))
using (var stream = await response.Content.ReadAsStreamAsync())
using (var memStream = new MemoryStream())
{
int receivedBytes = 0;
var totalBytes = Convert.ToInt32(response.Content.Headers.ContentLength);
while (true)
{
var buffer = new byte[4096];
int bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);
//write the current loop's bytes into the MemoryStream that will be returned
await memStream.WriteAsync(buffer, 0, bytesRead);
if (bytesRead == 0)
{
break;
}
receivedBytes += bytesRead;
var args = new DownloadProgressArgs(receivedBytes, totalBytes);
progessReporter.Report(args);
}
memStream.Position = 0;
var stringContent = new StreamReader(memStream);
return stringContent.ReadToEnd();
}
}
finally
{
client.Dispose();
}
}