Code showing how to set up your Azure Function to authorize bot framework requests

AzureFunctionBotFrameworkAuthorization.cs

using (BotService.Initialize())
{
	// authenticate incoming request and add activity.ServiceUrl to MicrosoftAppCredentials.TrustedHostNames
	// if request is authenticated
	if (!await BotService.Authenticator.TryAuthenticateAsync(req, new[]
	{
		activity
	},CancellationToken.None))
	{
		return BotAuthenticator.GenerateUnauthorizedResponse(req);
	}
	return new HttpResponseMessage(HttpStatusCode.OK);
}