private bool IsValidResponse(IRecaptchaModel viewModel)
{
// bool IsValidResponse(string challenge, string response, string clientIP, string privateKey, string validationUrl, Action<string> loggingFunction)
if (viewModel.recaptcha_challenge_field == null || viewModel.recaptcha_response_field == null || viewModel.ClientIP == null)
{
_loggingFunction(string.Format("Problem with Captcha. One or more of the required Captcha parts is null (challenge, response, or clientIP). Asking client to re-try. If this happens repeatedly it may indicate a change to the Captcha API. (did not cause a user visible exception)\r\nchallenge: {0}\r\nresponse: {1}\r\nclientIP: {2}.",
viewModel.recaptcha_challenge_field,
viewModel.recaptcha_response_field,
viewModel.ClientIP));
return(false);
}
var request = (HttpWebRequest)WebRequest.Create(viewModel.ValidationUrl);
request.ProtocolVersion = HttpVersion.Version10;
request.Timeout = 30 * 1000;
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
string formdata = string.Format("privatekey={0}&remoteip={1}&challenge={2}&response={3}"
, new object[]
{
HttpUtility.UrlEncode(viewModel.PrivateKey)
, HttpUtility.UrlEncode(viewModel.ClientIP)
, HttpUtility.UrlEncode(viewModel.recaptcha_challenge_field)
, HttpUtility.UrlEncode(viewModel.recaptcha_response_field)
});
byte[] formbytes = Encoding.ASCII.GetBytes(formdata);
using (var requestStream = request.GetRequestStream())
{
requestStream.Write(formbytes, 0, formbytes.Length);
}
using (var httpResponse = request.GetResponse())
{
Stream stream = httpResponse.GetResponseStream();
if (stream != null)
{
using (var readStream = new StreamReader(stream, Encoding.UTF8))
{
string[] results = readStream.ReadToEnd().Split(new char[0]);
switch (results[0])
{
case "true":
return(true);
case "false":
return(false);
default:
throw new InvalidProgramException(string.Format("Unknown status response \"{0}\" from Recaptcha validation call.", results[0]));
}
}
}
}
return(false);
}
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
IRecaptchaModel viewModel = base.BindModel(controllerContext, bindingContext) as IRecaptchaModel;
if (viewModel == null)
{
throw new ArgumentException("Unable to bind RecaptchaModel");
}
viewModel.ClientIP = controllerContext.HttpContext.Request.UserHostAddress;
viewModel.PrivateKey = _privateKey;
viewModel.ValidationUrl = _validationUrl;
if (_validateOnBind)
{
viewModel.IsValid = IsValidResponse(viewModel);
if (!viewModel.IsValid)
{
bindingContext.ModelState.AddModelError("IRecaptchaModel", "Invalid Recaptcha Response");
}
}
return(viewModel);
}