public async Task <CoapMessage> ObserveAsync(CoapMessage message)
{
if (!message.Observe.HasValue)
{
//RST because GET needs to be observe/unobserve
Trace.TraceWarning("{0} - CoAP observe received without Observe flag set on channel '{1}', returning RST", DateTime.UtcNow.ToString("yyyy-MM-ddTHH-MM-ss.fffff"), channel.Id);
return(new CoapResponse(message.MessageId, ResponseMessageType.Reset, ResponseCodeType.EmptyMessage));
}
CoapUri uri = new CoapUri(message.ResourceUri.ToString());
ResponseMessageType rmt = message.MessageType == CoapMessageType.Confirmable ? ResponseMessageType.Acknowledgement : ResponseMessageType.NonConfirmable;
if (!await adapter.CanSubscribeAsync(uri.Resource, channel.IsEncrypted))
{
//not authorized
Trace.TraceWarning("{0} - CoAP observe not authorized on channel '{1}'", DateTime.UtcNow.ToString("yyyy-MM-ddTHH-MM-ss.fffff"), channel.Id);
return(new CoapResponse(message.MessageId, rmt, ResponseCodeType.Unauthorized, message.Token));
}
if (!message.Observe.Value)
{
//unsubscribe
Trace.TraceWarning("{0} - CoAP observe with value on channel '{1}', unsubscribing.", DateTime.UtcNow.ToString("yyyy-MM-ddTHH-MM-ss.fffff"), channel.Id);
await adapter.UnsubscribeAsync(uri.Resource);
coapObserved.Remove(uri.Resource);
}
else
{
//subscribe
SubscriptionMetadata metadata = new SubscriptionMetadata()
{
IsEphemeral = true,
Identity = session.Identity,
Indexes = session.Indexes
};
string subscriptionUriString = await adapter.SubscribeAsync(uri.Resource, metadata);
if (!coapObserved.ContainsKey(uri.Resource)) //add resource to observed list
{
coapObserved.Add(uri.Resource, message.Token);
}
}
return(new CoapResponse(message.MessageId, rmt, ResponseCodeType.Valid, message.Token));
}
private void Session_OnUnsubscribe(object sender, MqttMessageEventArgs args)
{
try
{
UnsubscribeMessage msg = (UnsubscribeMessage)args.Message;
foreach (var item in msg.Topics)
{
MqttUri uri = new MqttUri(item.ToLowerInvariant());
if (adapter.CanSubscribeAsync(uri.Resource, Channel.IsEncrypted).GetAwaiter().GetResult())
{
adapter.UnsubscribeAsync(uri.Resource).GetAwaiter();
}
}
}
catch (Exception ex)
{
logger.LogError(ex, $"MQTT adapter Session_OnUnsubscribe error on channel '{Channel.Id}'.");
OnError?.Invoke(this, new ProtocolAdapterErrorEventArgs(Channel.Id, ex));
}
}
private async Task SubscribeAsync(string resourceUriString, string identity, List <KeyValuePair <string, string> > indexes)
{
if (await adapter.CanSubscribeAsync(resourceUriString, Channel.IsEncrypted))
{
SubscriptionMetadata metadata = new SubscriptionMetadata()
{
Identity = identity,
Indexes = indexes,
IsEphemeral = true
};
string subscriptionUriString = await adapter.SubscribeAsync(resourceUriString, metadata);
//await Log.LogInfoAsync("Identity {0} subscribed to resource {1} with subscription URI {2}", identity, resourceUriString, subscriptionUriString);
}
else
{
//await Log.LogErrorAsync("REST protocol cannot subscribe identity {0} to resource {1}", identity, resourceUriString);
}
}
