C# StreamContent.CopyToAsync方法代码示例

		public void CopyToAsync ()
		{
			var ms = new MemoryStream ();
			ms.WriteByte (4);
			ms.WriteByte (2);
			ms.Seek (0, SeekOrigin.Begin);

			var sc = new StreamContent (ms);

			var dest = new MemoryStream ();
			var task = sc.CopyToAsync (dest);
			task.Wait ();
			Assert.AreEqual (2, dest.Length, "#1");

			bool hit = false;
			dest = new MemoryStream ();
			var scm = new StreamContentMock (new ExceptionStream ());
			scm.OnSerializeToStreamAsync = () => { hit = true; };
			task = scm.CopyToAsync (dest);
			try {
				task.Wait ();
				Assert.Fail ("#9");
			} catch (AggregateException) {
			}

			Assert.IsTrue (hit, "#10");
		}

		public void CopyToAsync_ClosedInput ()
		{
			var stream = new MemoryStream (new byte[] { 1 });
			var content = new StreamContent (stream);
			Assert.IsTrue (content.LoadIntoBufferAsync ().Wait (3000), "#1");
			stream.Close ();

			var stream_out = new MemoryStream (10);
			Assert.IsTrue (content.CopyToAsync (stream_out).Wait (3000), "#2");
		}

		public void CopyToAsync_Invalid ()
		{
			var m = new MemoryStream ();

			var sc = new StreamContent (new MemoryStream ());
			try {
				sc.CopyToAsync (null);
				Assert.Fail ("#1");
			} catch (ArgumentNullException) {
			}

			//
			// For some reason does not work on .net
			//
			/*
			sc = new StreamContent (new ExceptionStream ());
			try {
			    sc.CopyToAsync (m).Wait ();
			    Assert.Fail ("#2");
			} catch (AggregateException) {
			}
			*/ 
		}

        private static async Task<HttpContent> CreateBufferedRequestContentAsync(IOwinRequest owinRequest,
            CancellationToken cancellationToken)
        {
            // We need to replace the request body with a buffered stream so that other components can read the stream.
            // For this stream to be useful, it must NOT be diposed along with the request. Streams created by
            // StreamContent do get disposed along with the request, so use MemoryStream to buffer separately.
            MemoryStream buffer;
            int? contentLength = owinRequest.GetContentLength();

            if (!contentLength.HasValue)
            {
                buffer = new MemoryStream();
            }
            else
            {
                buffer = new MemoryStream(contentLength.Value);
            }

            cancellationToken.ThrowIfCancellationRequested();

            using (StreamContent copier = new StreamContent(owinRequest.Body))
            {
                await copier.CopyToAsync(buffer);
            }

            // Provide the non-disposing, buffered stream to later OWIN components (set to the stream's beginning).
            buffer.Position = 0;
            owinRequest.Body = buffer;

            // For MemoryStream, Length is guaranteed to be an int.
            return new ByteArrayContent(buffer.GetBuffer(), 0, (int)buffer.Length);
        }