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Fix issues in RPC extension.

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This commit is contained in:
Christian
2018-04-11 22:19:38 +02:00
parent ec41efd860
commit 1df6798934
8 changed files with 70 additions and 58 deletions
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Extensions/MQTTnet.Extensions.Rpc/MqttRpcClient.cs
+10 -20
View File
@@ -1,5 +1,6 @@
using System;
using System.Collections.Concurrent;
using System.Text;
using System.Threading.Tasks;
using MQTTnet.Client;
using MQTTnet.Internal;
@@ -9,11 +10,9 @@ namespace MQTTnet.Extensions.Rpc
{
public sealed class MqttRpcClient : IDisposable
{
private const string ResponseTopic = "$MQTTnet.RPC/+/+/response";
private readonly ConcurrentDictionary<string, TaskCompletionSource<byte[]>> _waitingCalls = new ConcurrentDictionary<string, TaskCompletionSource<byte[]>>();
private readonly IMqttClient _mqttClient;
private bool _isEnabled;
public MqttRpcClient(IMqttClient mqttClient)
{
_mqttClient = mqttClient ?? throw new ArgumentNullException(nameof(mqttClient));
@@ -21,16 +20,9 @@ namespace MQTTnet.Extensions.Rpc
_mqttClient.ApplicationMessageReceived += OnApplicationMessageReceived;
}
public async Task EnableAsync()
public Task<byte[]> ExecuteAsync(TimeSpan timeout, string methodName, string payload, MqttQualityOfServiceLevel qualityOfServiceLevel)
{
await _mqttClient.SubscribeAsync(new TopicFilterBuilder().WithTopic(ResponseTopic).WithAtLeastOnceQoS().Build());
_isEnabled = true;
}
public async Task DisableAsync()
{
await _mqttClient.UnsubscribeAsync(ResponseTopic);
_isEnabled = false;
return ExecuteAsync(timeout, methodName, Encoding.UTF8.GetBytes(payload), qualityOfServiceLevel);
}
public async Task<byte[]> ExecuteAsync(TimeSpan timeout, string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel)
@@ -42,12 +34,7 @@ namespace MQTTnet.Extensions.Rpc
throw new ArgumentException("The method name cannot contain /, + or #.");
}
if (!_isEnabled)
{
throw new InvalidOperationException("The RPC client is not enabled.");
}
var requestTopic = $"$MQTTnet.RPC/{Guid.NewGuid():N}/{methodName}";
var requestTopic = $"MQTTnet.RPC/{Guid.NewGuid():N}/{methodName}";
var responseTopic = requestTopic + "/response";
var requestMessage = new MqttApplicationMessageBuilder()
@@ -64,18 +51,21 @@ namespace MQTTnet.Extensions.Rpc
throw new InvalidOperationException();
}
await _mqttClient.PublishAsync(requestMessage);
await _mqttClient.SubscribeAsync(responseTopic, qualityOfServiceLevel).ConfigureAwait(false);
await _mqttClient.PublishAsync(requestMessage).ConfigureAwait(false);
return await tcs.Task.TimeoutAfter(timeout);
}
finally
{
_waitingCalls.TryRemove(responseTopic, out _);
await _mqttClient.UnsubscribeAsync(responseTopic).ConfigureAwait(false);
}
}
private void OnApplicationMessageReceived(object sender, MqttApplicationMessageReceivedEventArgs eventArgs)
{
if (!_waitingCalls.TryRemove(eventArgs.ApplicationMessage.Topic, out TaskCompletionSource<byte[]> tcs))
if (!_waitingCalls.TryRemove(eventArgs.ApplicationMessage.Topic, out var tcs))
{
return;
}
Extensions/MQTTnet.Extensions.Rpc/SampleCCode.c
+28 -1
View File
@@ -1 +1,28 @@

// If using the MQTT client PubSubClient it must be ensured that the request topic for each method is subscribed like the following.
_mqttClient.subscribe("MQTTnet.RPC/+/ping");
_mqttClient.subscribe("MQTTnet.RPC/+/do_something");
// It is not allowed to change the structure of the topic. Otherwise RPC will not work. So method names can be separated using
// an _ or . but no +, # or /.. If it is required to distinguish between devices own rules can be defined like the following.
_mqttClient.subscribe("MQTTnet.RPC/+/deviceA.ping");
_mqttClient.subscribe("MQTTnet.RPC/+/deviceB.ping");
_mqttClient.subscribe("MQTTnet.RPC/+/deviceC.getTemperature");
// Within the callback of the mqtt client the topic must be checked if it belongs to MQTTnet RPC. The following code shows one
// possible way.
void mqtt_Callback(char *topic, byte *payload, unsigned int payloadLength)
{
String topicString = String(topic);
if (topicString.startsWith("MQTTnet.RPC/")) {
String responseTopic = topicString + String("/response");
if (topicString.endsWith("/deviceA.ping")) {
mqtt_publish(responseTopic, "pong", false);
return;
}
}
}
// Do not send response message with the _retain_ flag set to true.
// All required data for a RPC call and the result must be placed into the payload.