/// <inheritdoc cref="ICaptcha.Create" />
public void Create(HttpContext context)
{
var feature = GetCaptchaFeature(context);
if (feature.HasCaptchaToken)
{
store.InvalidateCaptcha(context, feature.CaptchaToken);
}
var text = textGenerator.Generate();
var blob = new BinaryBlob(256);
var token = new CaptchaToken(blob);
var cookie = options.Cookie.Build(context);
var captcha = new GeneratedCaptcha(token, text, DateTime.UtcNow);
store.SetCaptcha(context, captcha);
context.Response.Cookies.Append(
options.Cookie.Name,
WebEncoders.Base64UrlEncode(token.Value.GetData()),
cookie
);
logger.LogDebug($"New CAPTCHA was generated: {options.Cookie.Name}={blob.DebugString}");
}
private async Task ImageContentAsync(HttpContext context, GeneratedCaptcha info)
{
var routeData = context.GetRouteData() ?? new RouteData();
var actionContext = new ActionContext(context, routeData, emptyActionDescriptor);
var headers = new RequestHeaders(context.Request.Headers);
using (var stream = new MemoryStream())
{
var codec = GetImageCodec(options.Image.Format);
if (false == CanClientAccept(headers.Accept, codec.MimeType))
{
return;
}
using (var image = await generator.GenerateImageAsync(info.Captcha))
{
var encoderContext = new GeneratedCaptchaImageContext(codec);
var args = options.Image.EncoderParameters.Invoke(encoderContext);
image.Save(stream, codec, args);
}
var contentType = new MediaTypeHeaderValue(codec.MimeType, 1.0d);
var result = new FileContentResult(stream.ToArray(), contentType);
await result.ExecuteResultAsync(actionContext);
}
}
public void SetCaptcha(HttpContext context, GeneratedCaptcha captcha)
{
if (null == context)
{
throw new ArgumentNullException(nameof(context));
}
if (null == captcha)
{
throw new ArgumentNullException(nameof(captcha));
}
var token = captcha.Token;
cache[token.Value] = captcha;
}
internal static bool NotExpired(GeneratedCaptcha captcha, TimeSpan timeout)
{
var duration = DateTime.UtcNow - captcha.CreatedAt;
return(duration <= timeout);
}