CODEWITHSUNDEEP
c#postutf-8httpwebrequest
Broam
Broam

Reputation: 4648

Why am I running out of bytes for the stream while performing an HTTP POST?

This is driving me nuts:

    WebRequest request = WebRequest.Create(url);
    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";
    request.ContentLength = Encoding.UTF8.GetByteCount(data);
    Stream reqs = request.GetRequestStream();
    StreamWriter stOut = new StreamWriter(reqs, Encoding.UTF8);
    stOut.Write(data);
    stOut.Flush();

I get an exception that I've run out of bytes in the stream...but I've used the same encoding to get the byte count!

Using ASCII this doesn't fail. Is this because of the UTF-8 BOM that Windows likes to add in?

Upvotes: 1

Views: 476

Answers (3)

Hans Passant
Hans Passant

Reputation: 941515

Don't forget to actually URL-encode the data, like you promised in the ContentType. It's a one-liner:

byte[] bytes = System.Web.HttpUtility.UrlEncodeToBytes(data, Encoding.UTF8);

Upvotes: 1

João Angelo
João Angelo

Reputation: 57688

You can also try something like this:

byte[] bytes = Encoding.UTF8.GetBytes(data);

request.ContentLength = bytes.Length;
request.GetRequestStream().Write(bytes, 0, bytes.Length);

Upvotes: 1

Marc Gravell
Marc Gravell

Reputation: 1062820

This is probably the BOM; try using an explicit encoding without a BOM:

Encoding enc = new UTF8Encoding(false);
...
request.ContentLength = enc.GetByteCount(data);
...
StreamWriter stOut = new StreamWriter(reqs, enc);

Even easier; switch to WebClient instead and of trying to handle it all yourself; it is very easy to post a form with this:

    using (var client = new WebClient())
    {
        var data = new NameValueCollection();
        data["foo"] = "123";
        data["bar"] = "456";
        byte[] resp = client.UploadValues(address, data);
    }

Or with the code from here:

  byte[] resp = client.Post(address, new {foo = 123, bar = 546});

Upvotes: 3

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