private async Task PostOrDeleteSubscriber(IHttpResourceRequest request, IHttpResourceResponse response,
TopicName topic)
{
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (response == null)
{
throw new ArgumentNullException(nameof(response));
}
var uri = request.QueryString["uri"];
if (uri == null)
{
response.StatusCode = 400;
response.StatusDescription = "Subscriber URI is required";
return;
}
var subscriber = new Uri(uri);
if (!_topics.Contains(topic))
{
response.StatusCode = 404;
response.StatusDescription = "Topic not found";
return;
}
var authorized = _authorizationService == null ||
await _authorizationService.IsAuthorizedToSubscribe(request.Principal, topic);
if (!authorized)
{
response.StatusCode = 401;
response.StatusDescription = "Unauthorized";
return;
}
if ("delete".Equals(request.HttpMethod, StringComparison.OrdinalIgnoreCase))
{
// TODO: Verify that the subscriber is the one deleting the subscription
// Ideas: Issue another HTTP request back to the subscriber to verify?
// Require the subscriber to specify a subscription ID (GUID?)
// when subscribing and then supply the same ID when unsubscribing?
await _subscriptionTrackingService.RemoveSubscription(topic, subscriber);
}
else
{
var ttlStr = request.QueryString["ttl"];
var ttl = string.IsNullOrWhiteSpace(ttlStr)
? default(TimeSpan)
: TimeSpan.FromSeconds(int.Parse(ttlStr));
await _subscriptionTrackingService.AddSubscription(topic, subscriber, ttl);
}
response.StatusCode = 200;
}
private async Task HandleReceiveResult(UdpReceiveResult result)
{
try
{
var datagram = SubscriptionTrackingDatagram.Decode(result.Buffer);
if (datagram.NodeId == _nodeId)
{
return;
}
switch (datagram.Action)
{
case SubscriptionTrackingDatagram.ActionType.Add:
await _inner.AddSubscription(datagram.Topic, datagram.SubscriberUri, datagram.TTL);
return;
case SubscriptionTrackingDatagram.ActionType.Remove:
await _inner.RemoveSubscription(datagram.Topic, datagram.SubscriberUri);
return;
default:
await _diagnosticService.EmitAsync(new MulticastEventBuilder(this, MulticastEventType.MalformedDatagram)
{
Detail = "Unknown or unsupported subscription tracking action: " + datagram.Action,
Node = _nodeId.ToString(),
Host = result.RemoteEndPoint.Address.ToString(),
Port = result.RemoteEndPoint.Port
}.Build());
break;
}
}
catch (Exception e)
{
_diagnosticService.Emit(new MulticastEventBuilder(this, MulticastEventType.MalformedDatagram)
{
Detail = "Error unmarshaling datagram",
Node = _nodeId.ToString(),
Host = result.RemoteEndPoint.Address.ToString(),
Port = result.RemoteEndPoint.Port,
Exception = e
}.Build());
}
}