/// <summary>
/// Verifies the verify token from the message. If the token matches the one configured, sends back the challenge.
/// </summary>
/// <param name="request">Represents the incoming side of an HTTP request.</param>
/// <param name="response">Represents the outgoing side of an HTTP request.</param>
/// <param name="cancellationToken">A cancellation token that can be used by other objects
/// or threads to receive notice of cancellation.</param>
/// <returns>A task that represents the work queued to execute.</returns>
/// <exception cref="ArgumentNullException"><paramref name="request"/> or <paramref name="response"/> is null.</exception>
public virtual async Task VerifyWebhookAsync(HttpRequest request, HttpResponse response, CancellationToken cancellationToken)
{
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (response == null)
{
throw new ArgumentNullException(nameof(response));
}
var challenge = string.Empty;
HttpStatusCode statusCode;
if (request.Query["hub.verify_token"].Equals(_options.FacebookVerifyToken))
{
challenge = request.Query["hub.challenge"];
statusCode = HttpStatusCode.OK;
}
else
{
statusCode = HttpStatusCode.Unauthorized;
}
await FacebookHelper.WriteAsync(response, statusCode, challenge, Encoding.UTF8, cancellationToken).ConfigureAwait(false);
}
/// <summary>
/// Accepts an incoming webhook request, creates a turn context,
/// and runs the middleware pipeline for an incoming TRUSTED activity.
/// </summary>
/// <param name="httpRequest">Represents the incoming side of an HTTP request.</param>
/// <param name="httpResponse">Represents the outgoing side of an HTTP request.</param>
/// <param name="bot">The code to run at the end of the adapter's middleware pipeline.</param>
/// <param name="cancellationToken">A cancellation token that can be used by other objects
/// or threads to receive notice of cancellation.</param>
/// <returns>A task that represents the work queued to execute.</returns>
/// <exception cref="AuthenticationException">The webhook receives message with invalid signature.</exception>
public async Task ProcessAsync(HttpRequest httpRequest, HttpResponse httpResponse, IBot bot, CancellationToken cancellationToken = default)
{
if (httpRequest.Query["hub.mode"] == HubModeSubscribe && _options.VerifyIncomingRequests)
{
await _facebookClient.VerifyWebhookAsync(httpRequest, httpResponse, cancellationToken).ConfigureAwait(false);
return;
}
string stringifiedBody;
using (var sr = new StreamReader(httpRequest.Body))
{
stringifiedBody = await sr.ReadToEndAsync().ConfigureAwait(false);
}
if (!_facebookClient.VerifySignature(httpRequest, stringifiedBody) && _options.VerifyIncomingRequests)
{
await FacebookHelper.WriteAsync(httpResponse, HttpStatusCode.Unauthorized, string.Empty, Encoding.UTF8, cancellationToken).ConfigureAwait(false);
throw new AuthenticationException("Webhook received message with invalid signature. Potential malicious behavior!");
}
FacebookResponseEvent facebookResponseEvent = null;
facebookResponseEvent = JsonConvert.DeserializeObject <FacebookResponseEvent>(stringifiedBody);
foreach (var entry in facebookResponseEvent.Entry)
{
var payload = entry.Changes.Count > 0 ? entry.Changes : entry.Messaging.Count > 0 ? entry.Messaging : entry.Standby.Count > 0 ? entry.Standby : new List <FacebookMessage>();
foreach (var message in payload)
{
message.IsStandby = entry.Standby.Count > 0;
var activity = FacebookHelper.ProcessSingleMessage(message);
using (var context = new TurnContext(this, activity))
{
await RunPipelineAsync(context, bot.OnTurnAsync, cancellationToken).ConfigureAwait(false);
}
}
}
}
/// <summary>
/// Factory method to create the <see cref="FacebookMessage"/> instance of the <see cref="Activity"/> to be sent to Facebook.
/// </summary>
/// <remarks>
/// This lets an override add a Facebook-supported message tag to an outgoing message.
/// See https://developers.facebook.com/docs/messenger-platform/send-messages/message-tags/.
/// </remarks>
/// <param name="activity">An <see cref="Activity"/> instance to build the message.</param>
/// <returns>A <see cref="FacebookMessage"/> built from the activity instance.</returns>
protected virtual FacebookMessage CreateFacebookMessageFromActivity(Activity activity)
{
return(FacebookHelper.ActivityToFacebook(activity));
}