JSON truncated when compressing HTTP responses

Question

When I apply gzip or deflate compression to my HTTP responses, I seem to be losing the last bracket in my JSON structures. For example:

Result without compression:

{"alist":{"P_1":0,"P_2":0,"P_3":0}}

Result with compression as received by the browser:

{"alist":{"P_1":0,"P_2":0,"P_3":0}

When writing the response without compression I am doing the following:

byte[] buffer = Encoding.UTF8.GetBytes(responseContent);

context.Response.ContentLength64 = buffer.Length;
context.Response.ContentType = ContentTypeJson;

Stream outputStream = context.Response.OutputStream;
outputStream.Write(buffer, 0, buffer.Length);
outputStream.Close();

Alternatively, when the caller provides an Accept-Encoding request header, I try and write the response with compression as follows;

byte[] buffer = Encoding.UTF8.GetBytes(responseContent);
byte[] compressedBuffer;

using (var memoryStream = new MemoryStream())
{
    using (Stream compressionStream = new DeflateStream(memoryStream, CompressionMode.Compress, false))
    {
        compressionStream.Write(buffer, 0, buffer.Length);

        compressedBuffer = memoryStream.ToArray();

        compressionStream.Close();
    }

    memoryStream.Close();
}

context.Response.ContentLength64 = compressedBuffer.Length;
context.Response.ContentType = ContentTypeJson;

Stream outputStream = context.Response.OutputStream;
outputStream.Write(compressedBuffer, 0, compressedBuffer.Length);
outputStream.Close();

If it helps, I am using an System.Net.HttpListener which is why I have to do this myself. Does anyone have any idea why this truncation may be occuring?

Answer 1

DeflateStream doesn't write to its output stream everything immediately after you write into it, but you can be sure it has done so after you close it. So the following will work:

compressionStream.Write(buffer, 0, buffer.Length);

compressionStream.Close();

compressedBuffer = memoryStream.ToArray();