HttpRequest OutOfMemoryException on Windows CE

0 votes
asked Nov 8, 2017 by rayo (120 points)
edited Nov 9, 2017 by rayo

I am trying to use HttpRequest to stream large files to a web api from a limited memory Windows CE device. The exception is thrown while writing to the request stream. The same problem is not encountered when using HttpWebRequest. I am attempting to use HttpRequest for its TLS support.

Is HttpRequest buffering the content stream? Is there any way to mimic the functionality of HttpWebRequest's AllowWriteStreamBuffering=false or SendChunked=true?

The code is roughly as follows:

string formDataBoundary = String.Format("----------{0:N}", Guid.NewGuid());
var webRequest = DdfWebRequest.Create(postUrl);
webRequest.ContentType = "multipart/form-data; boundary=" + formDataBoundary;
webRequest.Method = "POST";

// Determine the ContentLength before opening the request stream              
webRequest.ContentLength = DetermineStreamSize(reportFiles);

// Write form and file data to request stream
using (Stream requestStream = webRequest.GetRequestStream())
    string fd;
    foreach (string reportFile in reportFiles)
        fd = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\"\r\n\r\n", formDataBoundary,
                                   reportId.ToString(), Path.GetFileName(reportFile));
        requestStream.Write(Encoding.UTF8.GetBytes(fd), 0, Encoding.UTF8.GetByteCount(fd));

        // Get the file content
        FileStream fs = new FileStream(reportFile, FileMode.Open, FileAccess.Read);
        byte[] data = new byte[2048];
        int k = 0;
        for (int i = 0; i < fs.Length; i+=k)
            k = fs.Read(data, 0, data.Length);
            if (k > 0)
                requestStream.Write(data, 0, k);
        requestStream.Write(Encoding.UTF8.GetBytes("\r\n"), 0, 2);
    // Add last boundary
    string footer = "\r\n--" + formDataBoundary + "--\r\n";
    requestStream.Write(Encoding.UTF8.GetBytes(footer), 0, Encoding.UTF8.GetByteCount(footer));

// Get the response from the JetLink
HttpResponse webResponse = (HttpResponse)webRequest.GetResponse();

// Get the response from the JetLink
HttpResponse webResponse = (HttpResponse)webRequest.GetResponse();
Applies to: Rebex HTTPS

2 Answers

0 votes
answered Nov 9, 2017 by Lukas Pokorny (126,910 points)
edited Jan 12, 2018 by Lukas Pokorny

Update: Rebex HTTPS 2017 R6.2 supports AllowWriteStreamBuffering and SendChunked.

Unfortunately, on-the-fly uploads (AllowWriteStreamBuffering=false) and chunked upload mode (SendChunked=true) are not implemented yet. Sorry!

However, these features are currently on top of our list of enhancements and will appear in one of the next releases.

We currently have a partially-finished beta that implements AllowWriteStreamBuffering=false. When we add SendChunked=true as well, I'll send you a link to a beta package to try.

0 votes
answered Dec 5, 2017 by Lukas Pokorny (126,910 points)

We have published a hotfix that adds AllowWriteStreamBuffering and SendChunked properties. I have sent a download link to your e-mail address. This will be included in the next release of Rebex HTTPS as well.

commented Dec 20, 2017 by anonymous
Hi Lukas,
I would like to have this hotfix in order to avoid OutOfMemoryException.
Can you send it to me?
Thank you so much

Best regards

commented Dec 20, 2017 by Lukas Pokorny (126,910 points)
Hi Mauro, I have just sent a link to the hotfix to your e-mail address.
commented Jan 12, 2018 by Lukas Pokorny (126,910 points)
We have released a new version of Rebex HTTPS with support for AllowWriteStreamBuffering and SendChunked properties: