For me, 'webClient.UseDefaultCredentials = true;' solves it only on local, not in the web app on the server connecting to another server. I couldn't add the needed credential into Windows as a user, but I found later some programming way - I won't test it as I already made own solution. And also I don't want to mangle with the web server's registry, even if I have the needed admin rights. All these problems are because of the Windows internal handling of the NTLM authentication ("Windows Domain") and all of libraries and frameworks built over that (e.g. .NET).
So the solution for me was quite simple in idea - create a proxy app in a multiplatform technology with a multiplatform NTLM library where the NTLM communication is created by hand according to the public specs, not by running the built-in code in Windows. I myself chose Node.js and the httpntlm library, because it's about only one single source file with few lines and calling it from .NET as a program returning the downloaded file (also I prefer transferring it through the standard output instead of creating a temporary file).
Node.js program as a proxy to download a file behind the NTLM authentication:
var httpntlm = require('httpntlm'); // https://github.com/SamDecrock/node-http-ntlm
//var fs = require('fs');
var login = 'User';
var password = 'Password';
var domain = 'Domain';
var file = process.argv.slice(2); // file to download as a parameter
httpntlm.get({
url: 'https://server/folder/proxypage.aspx?filename=' + file,
username: login,
password: password,
workstation: '',
domain: domain,
binary: true // don't forget for binary files
}, function (err, res/*ponse*/) {
if (err) {
console.log(err);
} else {
if (res.headers.location) { // in my case, the server redirects to a similar URL,
httpntlm.get({ // now containing the session ID
url: 'https://server' + res.headers.location,
username: login,
password: password,
workstation: '',
domain: domain,
binary: true // don't forget for binary files
}, function (err, res) {
if (err) {
console.log(err);
} else {
//console.log(res.headers);
/*fs.writeFile("434980.png", res.body, function (err) { // test write
if (err) // to binary file
return console.log("Error writing file");
console.log("434980.png saved");
});*/
console.log(res.body.toString('base64')); // didn't find a way to output
} // binary file, toString('binary')
}); // is not enough (docs say it's
// just 'latin1')...
} else { // if there's no redirect
//console.log(res.headers); // ...so I output base64 and
console.log(res.body.toString('base64')); // convert it back in the caller
} // code
}
});
.NET caller code (the web app downloading files from a web app on another server)
public static string ReadAllText(string path)
{
if (path.StartsWith("http"))
return System.Text.Encoding.Default.GetString(ReadAllBytes(path));
else
return System.IO.File.ReadAllText(path);
}
public static byte[] ReadAllBytes(string path)
{
if (path.StartsWith("http"))
{
ProcessStartInfo psi = new ProcessStartInfo();
psi.FileName = "node.exe"; // Node.js installs into the PATH
psi.Arguments = "MyProxyDownladProgram.js " +
path.Replace("the base URL before the file name", "");
psi.WorkingDirectory = "C:\\Folder\\With My\\Proxy Download Program";
psi.UseShellExecute = false;
psi.CreateNoWindow = true;
psi.RedirectStandardInput = true;
psi.RedirectStandardOutput = true;
psi.RedirectStandardError = true;
Process p = Process.Start(psi);
byte[] output;
try
{
byte[] buffer = new byte[65536];
using (var ms = new MemoryStream())
{
while (true)
{
int read = p.StandardOutput.BaseStream.Read(buffer, 0, buffer.Length);
if (read <= 0)
break;
ms.Write(buffer, 0, read);
}
output = ms.ToArray();
}
p.StandardOutput.Close();
p.WaitForExit(60 * 60 * 1000); // wait up to 60 minutes
if (p.ExitCode != 0)
throw new Exception("Exit code: " + p.ExitCode);
}
finally
{
p.Close();
p.Dispose();
}
// convert the outputted base64-encoded string to binary data
return System.Convert.FromBase64String(System.Text.Encoding.Default.GetString(output));
}
else
{
return System.IO.File.ReadAllBytes(path);
}
}
