Question

I have an iPad app that submits orders to an ASP.NET MVC web site via form post. It is posting JSON which can be fairly large for a mobile device to send (200~300K) under certain conditions. I can GZip the form post but then my asp.net mvc chokes on the gzipped content.

How can I handle a GZipped form post in asp.net mvc?

UPDATE:

Darin’s answer puts me on the right track but I still have no idea how to do what he suggests, so here is where I am at:

Have this code to decompress a string:

http://dotnet-snippets.com/dns/compress-and-decompress-strings-SID612.aspx

And I get the string like so:

StreamReader reader = new StreamReader(Request.InputStream);
string encodedString = reader.ReadToEnd();

but this gives me the error:

The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or a non-white space character among the padding characters.

EDIT – COMPLETED CODE

I am using asp.net MVC and this is working great for me. I also had to deal with some other encoding that happens when my gzipping occurs:

[Authorize]
[HttpPost]
[ValidateInput(false)]
public ActionResult SubmitOrder()
        {

            GZipStream zipStream = new GZipStream(Request.InputStream, CompressionMode.Decompress);
            byte[] streamBytes = ReadAllBytes(zipStream);
            var result = Convert.ToBase64String(streamBytes);
            string sample = System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(result));
            string escaped = Uri.UnescapeDataString(sample);

 // escaped now has my form values as a string like so: var1=value1&var2=value2&ect...

//more boring code

}



 public static byte[] ReadAllBytes(Stream input)
        {
            byte[] buffer = new byte[16 * 1024];
            using (MemoryStream ms = new MemoryStream())
            {
                int read;
                while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
                {
                    ms.Write(buffer, 0, read);
                }
                return ms.ToArray();
            }
        }

Answer 1

You can do this without a custom model binder. Write an Action that accepts HttpPostedFileBase, i.e, treat this as a file upload.

    [HttpPost]
    public ActionResult UploadCompressedJSON(HttpPostedFileBase file)
    {
        if (file != null && file.ContentLength > 0)
        {
            GZipStream zipStream = new GZipStream(file.InputStream, CompressionMode.Decompress);
            byte[] streamBytes = ReadAllBytes(zipStream);
            var result = Convert.ToBase64String(streamBytes);
        }
        return RedirectToAction("Index");
    }

You are going to need to change your client side code to send a file upload request but that should be fairly easy. For example you can look at this code.