/// <summary>
/// Shows the icon image based on the hash. The hash matches either the
/// correct or incorrect id and will fetch and show the right image.
/// </summary>
/// <param name="captchaId">The captcha identifier.</param>
/// <param name="hash">The icon hash.</param>
/// <returns>The icon as a FileStreamResult, or NULL.</returns>
public FileStream GetIconFromHash(int captchaId, string hash)
{
// Check if the hash and captcha id are set
if ((!String.IsNullOrEmpty(hash) && hash.Length == 48) && captchaId > -1)
{
_sessionData = SessionHolder;
// Check the amount of times an icon has been requested
if (_sessionData.IconRequests >= 5)
{
throw new IconCaptchaException("You are not allowed to view this page.");
}
// Update the request counter
_sessionData.IconRequests += 1;
SessionHolder = _sessionData;
// Check if the hash is present in the session data
if (_sessionData.Hashes.Contains(hash))
{
var imagePath = GetIconFilePath(captchaId, hash);
FileStream iconFile = GetFileStream(imagePath);
// Check if the icon exists
if (iconFile != null)
{
return(iconFile);
}
}
}
return(null);
}
/// <summary>
/// Validates the user form submission. If the captcha is incorrect, it
/// will set the error variable and return false, else true.
/// </summary>
/// <param name="form">The submitted form data.</param>
/// <returns>NULL if the captcha was correct, an IconCaptchaException with an error message if it's not valid.</returns>
public bool ValidateSubmission(HttpRequest request)
{
if (request.Form != null)
{
// Set the captcha id property
int captchaId = Utils.ConvertToInt(request["captcha-idhf"]);
// Check if the captcha ID is set.
if (captchaId < 0)
{
throw new IconCaptchaException(GetErrorMessage(3, "The captcha ID was invalid."));
}
// If the session is not loaded yet, load it.
if (_sessionData == null)
{
_sessionData = SessionHolder;
}
// Check if the hidden captcha field is set.
if (!String.IsNullOrEmpty(request["captcha-hf"]))
{
// If the hashes match, the form can be submitted. Return true.
string hash = GetCorrectIconHash(captchaId);
if (_sessionData.Completed == true && hash == request["captcha-hf"])
{
return(true);
}
else
{
throw new IconCaptchaException(GetErrorMessage(0, "You've selected the wrong image."));
}
}
else
{
throw new IconCaptchaException(GetErrorMessage(1, "No image has been selected."));
}
}
else
{
throw new IconCaptchaException(GetErrorMessage(2, "You've not submitted any form."));
}
}
/// <summary>
/// Checks and sets the captcha session. If the user selected the
/// correct image, the value will be true, else false.
/// </summary>
/// <param name="captchaId">The captcha identifier.</param>
/// <param name="pickedHash">The selected icon's hash.</param>
/// <returns>TRUE if the correct image was selected, FALSE if not.</returns>
public bool SetSelectedAnswer(int captchaId, string pickedHash)
{
// Check if the captcha ID is valid
if (captchaId < 0)
{
return(false);
}
// If the session is not loaded yet, load it.
if (_sessionData == null)
{
_sessionData = SessionHolder;
}
// Check if the hash is set and matches the correct hash.
if (!String.IsNullOrEmpty(pickedHash) && (GetCorrectIconHash(captchaId) == pickedHash))
{
_sessionData.Completed = true;
// Unset the data to at least save some space in the session.
_sessionData.Clear();
SessionHolder = _sessionData;
return(true);
}
else
{
_sessionData.Completed = false;
SessionHolder = _sessionData;
// Set the clicked icon ID
if (_sessionData.Hashes.Contains(pickedHash))
{
int index = _sessionData.Hashes.IndexOf(pickedHash);
_sessionData.LastClicked = index + 1;
}
}
return(false);
}
/// <summary>
/// Return a correct icon hash + multiple incorrect hashes.
/// </summary>
/// <param name="captchaId">The captcha identifier.</param>
/// <param name="theme">The theme of the captcha.</param>
/// <returns>List containing the icon hashes.</returns>
public string[] GetCaptchaData(int captchaId, string theme)
{
int a = Utils.Random.Next(1, 91); // Get a random number (correct image)
int b = 0; // Get another random number (incorrect image)
// Load the session data, if there is any present.
// Default data will be used in case no data exists.
_sessionData = SessionHolder;
// If the session data doesn't exist, create a new instance.
if (_sessionData == null)
{
theme = (String.IsNullOrEmpty(theme)) ? Utils.SanitizeString(theme) : "light";
_sessionData = new IconCaptchaSession(theme);
}
// Pick a random number for the incorrect icon.
// Loop until a number is found which doesn"t match the correct icon ID.
int c = -1;
while (b == 0)
{
c = Utils.Random.Next(1, 91);
if (c != a)
{
b = c;
}
}
int d = -1; // At which position the correct hash will be stored in the array.
List <string> e = new List <string>(); // Array containing the hashes
// Pick a random number for the correct icon.
// Loop until a number is found which doesn"t match the previously clicked icon ID.
while (d == -1)
{
int f = Utils.Random.Next(1, 5);
int g = (_sessionData.LastClicked > -1) ? _sessionData.LastClicked : 0;
if (f != g)
{
d = f;
}
}
for (int i = 1; i < 6; i++)
{
if (i == d)
{
e.Add(GetImageHash("icon-" + a + "-" + i, captchaId));
}
else
{
e.Add(GetImageHash("icon-" + b + "-" + i, captchaId));
}
}
// Unset the previous session data
_sessionData.Clear();
// Set (or override) the hashes and reset the icon request count.
_sessionData.CorrectId = a;
_sessionData.IncorrectId = b;
_sessionData.Hashes = e;
_sessionData.CorrectHash = e[d - 1];
_sessionData.IconRequests = 0;
// Save the session data
SessionHolder = _sessionData;
// Return the JSON encoded array
return(e.ToArray());
}
