private string GetDisplayName(WebHookEvents webHookEvent)
{
var displayAttribute = typeof(WebHookEvents).GetMember(webHookEvent.ToString())[0].GetCustomAttribute <DisplayAttribute>();
if (displayAttribute != null && !string.IsNullOrEmpty(displayAttribute.Name))
{
return(displayAttribute.Name);
}
return(null);
}
public async Task Publish <T>(WebHookEvents webhookEvent, T data)
{
var webhookEventName = GetDisplayName(webhookEvent);
var dataJson = JsonSerializer.Serialize(data);
var maxRetryAttempts = 3;
var pauseBetweenFailures = TimeSpan.FromSeconds(2);
var circuitBreakerPolicy = Policy.Handle <Exception>().CircuitBreakerAsync(5, TimeSpan.FromSeconds(30));
System.Diagnostics.Debug.WriteLine("STARTING...");
var retryPolicy = Policy
.Handle <Exception>()
.WaitAndRetryAsync(maxRetryAttempts, i => pauseBetweenFailures,
onRetry: (response, delay, retryCount, context) =>
{
System.Diagnostics.Debug.WriteLine("RETRYING... - " + retryCount);
});
var webhookSubscriptions = _applicationDbContext.WebhookSubscriptions.Include(q => q.WebhookSubscriptionContentType).Where(q => q.IsActive == true && q.WebhookSubscriptionType.Name == WebhookSubscriptionTypes.All.ToString() || (q.WebhookSubscriptionAllowedEvents.Where(q => q.WebhookEvent.Name == webhookEventName).Any() == true)).ToList();
foreach (var webhookSubscription in webhookSubscriptions)
{
try
{
var options = new JsonSerializerOptions
{
WriteIndented = true,
Encoder = System.Text.Encodings.Web.JavaScriptEncoder.UnsafeRelaxedJsonEscaping
};
var hashJson = JsonSerializer.Serialize(new { Data = dataJson, Event = webhookEventName }, options);
var webhookEventEntity = _applicationDbContext.WebhookEvents.Where(q => q.Name == webhookEventName).SingleOrDefault();
if (webhookEventEntity != null)
{
var webhookPayloadEntity = new WebhookPayload()
{
WebhookEventId = webhookEventEntity.Id, Data = dataJson, Attempt = 0, Created = DateTime.Now
};
_applicationDbContext.WebhookPayloads.Add(webhookPayloadEntity);
_applicationDbContext.SaveChanges();
HttpContent httpContent = null;
if (webhookSubscription.WebhookSubscriptionContentType.Name == "application/json")
{
httpContent = new StringContent(hashJson, Encoding.UTF8, "application/json");
}
else
{
var formData = new Dictionary <string, string> {
{ "Data", dataJson }, { "Event", webhookEventName }
};
httpContent = new FormUrlEncodedContent(formData);
}
var secretBytes = Encoding.UTF8.GetBytes(webhookSubscription.Secret);
using (var hasher = new HMACSHA256(secretBytes))
{
var hashData = Encoding.UTF8.GetBytes(hashJson);
var sha256 = hasher.ComputeHash(hashData);
var headerValue = string.Format(CultureInfo.InvariantCulture, SignatureHeaderValueTemplate, BitConverter.ToString(sha256));
httpContent.Headers.Add(SignatureHeaderName, headerValue);
}
await retryPolicy.WrapAsync(circuitBreakerPolicy).ExecuteAsync(async() =>
{
var response = await _httpClient.PostAsync(webhookSubscription.PayloadUrl, httpContent);
_applicationDbContext.WebhookResponses.Add(new WebhookResponse()
{
Data = await response.Content.ReadAsStringAsync(), HttpStatusCode = (int)response.StatusCode, WebhookPayloadId = webhookPayloadEntity.Id
});
_applicationDbContext.SaveChanges();
if (!response.IsSuccessStatusCode)
{
var webhookPayload = _applicationDbContext.WebhookPayloads.Where(q => q.Id == webhookPayloadEntity.Id).SingleOrDefault();
if (webhookPayloadEntity != null)
{
webhookPayload.Attempt += 1;
_applicationDbContext.WebhookPayloads.Update(webhookPayload);
_applicationDbContext.SaveChanges();
}
}
response.EnsureSuccessStatusCode();
});
}
}
catch (Exception ex)
{
}
}
}