SSL WebRequest in Linux

Question

I'm facing some issues while developing a C# application which sends some data to a remote PHP script in a server through a POST method, using WebRequest.

My code is as follows:

string url = "https://myserver.com/myfolder/myscript.php";
string PostDataQuery = "q=this+is+a+demo";

System.Net.HttpWebRequest request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);
System.Net.HttpWebResponse response = null;
Uri aUri = new Uri(url);
string BaseURL_Domain = aUri.GetLeftPart(UriPartial.Authority);
string BaseURL = this.EstandaritzaURL(BaseURL_Domain);
try {
    request.ProtocolVersion = System.Net.HttpVersion.Version10;
    request.KeepAlive = false;
    request.AllowAutoRedirect = true;
    request.AutomaticDecompression = System.Net.DecompressionMethods.GZip | System.Net.DecompressionMethods.Deflate;
    request.Proxy = null;
    request.Timeout = 10000;
    request.ReadWriteTimeout = 4000;
    request.MaximumAutomaticRedirections = 3;
    request.ServicePoint.Expect100Continue = false;
    request.UseDefaultCredentials = true;
    request.Host = BaseURL;
    request.UserAgent = "Mozilla/5.0 (" + Environment.OSVersion.ToString() + ") " + Application.ProductName + " " + Application.ProductVersion;
    request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    //req.Referer = "";
    request.Headers.Add("Accept-Language", "ca,es;q=0.7,en;q=0.3");
    request.Headers.Add("Accept-Encoding", "gzip, deflate");
    request.Headers.Add("DNT", "1");

    if (method.ToLower().Trim() == "post")
    {
        //POST
        request.ContentType = "application/x-www-form-urlencoded";
        request.Method = "POST";

        byte[] PostData = System.Text.Encoding.ASCII.GetBytes(PostDataQuery);
        request.ContentLength = PostData.Length;

        System.IO.Stream postStream = request.GetRequestStream();
        postStream.Write(PostData, 0, PostData.Length);
        postStream.Flush();
        postStream.Close();
    }

} catch (Exception e) {
    MessageBox.Show(this, "HTTP request error: " + e.Message, "HTTP request error", MessageBoxButtons.OK, MessageBoxIcon.Information);
    return false;
}
try {
    response = (System.Net.HttpWebResponse)request.GetResponse();
    if (response == null) return false;
} catch (Exception e) {
    if (e.Message.Contains("404"))
        MessageBox.Show(this, "HTTP request error: " + e.Message + Environment.NewLine + "Page not found: " + url, "Error 404", MessageBoxButtons.OK, MessageBoxIcon.Information);
    return false;
}

And I also have the callback to accept the certificate:

public bool HTTPAcceptCertificate(object sender, System.Security.Cryptography.X509Certificates.X509Certificate certification, System.Security.Cryptography.X509Certificates.X509Chain chain, System.Net.Security.SslPolicyErrors sslPolicyErrors)
{
    return true;
}

That very same code works fine in Windows, but when ported to Linux (Mint) it times out in the line:

postStream.Write(PostData, 0, PostData.Length);

If I use HTTP instead of HTTPS, everything works fine. I'm not sure what is going on here. I thought it was a problem related to permissions, but after executing the application through SUDO, the problem persists.

Does anybody have any idea/clue on what to do next?

Thank you very much.

Answer 1

After two days struggling with this now it's fixed. The way to fix this was to upgrade Mono to version 5.8.0.108 from 5.4.1.7, so I presume that I was experiencing some kind of bug.

Thank you very much to the community for your time and effort, you are great!