Validation response for CloudEvents in ASP.NET Core Web API

cloudevents-options-webapi.cs

[HttpOptions]
public async Task<IActionResult> Options()
{
    using (var reader = new StreamReader(Request.Body, Encoding.UTF8))
    {
        // Retrieve the validation header fields
        var webhookRequestOrigin = HttpContext.Request.Headers["WebHook-Request-Origin"].FirstOrDefault();
        var webhookRequestCallback = HttpContext.Request.Headers["WebHook-Request-Callback"];
        var webhookRequestRate = HttpContext.Request.Headers["WebHook-Request-Rate"];
        
        // Respond with the appropriate origin and allowed rate to
        // confirm acceptance of incoming notications
        HttpContext.Response.Headers.Add("WebHook-Allowed-Rate", "*");
        HttpContext.Response.Headers.Add("WebHook-Allowed-Origin", webhookRequestOrigin);
    }

    return Ok();
}