Add extension method for subscriptions

Build/MQTTnet.Extensions.Rpc.nuspec

@@ -0,0 +1,47 @@
+<?xml version="1.0"?>
+<package >
+  <metadata>
+    <id>MQTTnet.Extensions.Rpc</id>
+    <version>2.6.0</version>
+    <authors>Christian Kratky</authors>
+    <owners>Christian Kratky</owners>
+    <licenseUrl>https://github.com/chkr1011/MQTTnet/blob/master/LICENSE</licenseUrl>
+    <projectUrl>https://github.com/chkr1011/MQTTnet</projectUrl>
+    <iconUrl>https://raw.githubusercontent.com/chkr1011/MQTTnet/master/Images/Logo_128x128.png</iconUrl>
+    <requireLicenseAcceptance>false</requireLicenseAcceptance>
+    <description>This is a extension library which allows executing synchronous device calls including a response using MQTTnet.</description>
+    <releaseNotes>* Initial version.
+    </releaseNotes>
+    <copyright>Copyright Christian Kratky 2016-2017</copyright>
+    <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags> 
+    <dependencies>
+      <group targetFramework="netstandard2.0">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+      <group targetFramework="netstandard1.3">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />  
+      </group>
+
+      <group targetFramework="netstandard2.0">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+      
+      <group targetFramework="uap10.0">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+        
+      <group targetFramework="net452">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+
+      <group targetFramework="net461">
+        <dependency id="MQTTnet" version="2.6.0-rc1" />
+      </group>
+    </dependencies>
+  </metadata>
+
+  <files>
+    <!-- .NET Standard 2.0 -->
+    <file src="..\Frameworks\MQTTnet.AspNetCore\bin\Release\netstandard2.0\MQTTnet.AspNetCore.*" target="lib\netstandard2.0\"/>
+  </files>
+</package>

Build/build.ps1

@@ -8,16 +8,26 @@ $path = &$vswhere -latest -products * -requires Microsoft.Component.MSBuild -pro
 if ($path) {
     $msbuild = join-path $path 'MSBuild\15.0\Bin\MSBuild.exe'
 
+	# Build the core library
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net452" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net461" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard1.3" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     &$msbuild ..\Frameworks\MQTTnet.Netstandard\MQTTnet.Netstandard.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
     
+	# Build the ASP.NET Core 2.0 extension
 	&$msbuild ..\Frameworks\MQTTnet.AspNetCore\MQTTnet.AspNetCore.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
 
+	# Build the RPC extension
+	&$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net452" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="net461" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard1.3" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+    &$msbuild ..\Extensions\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m
+
     Remove-Item .\NuGet -Force -Recurse
     New-Item -ItemType Directory -Force -Path .\NuGet
     .\NuGet.exe pack MQTTnet.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion
     .\NuGet.exe pack MQTTnet.AspNetCore.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion
+	.\NuGet.exe pack MQTTnet.Extensions.Rpc.nuspec -Verbosity detailed -Symbols -OutputDir "NuGet" -Version $nugetVersion
 }

Extensions/MQTTnet.Extensions.Rpc/MqttRpcClient.cs

@@ -9,7 +9,7 @@ namespace MQTTnet.Extensions.Rpc
 {
     public sealed class MqttRpcClient : IDisposable
     {
-        private const string ResponseTopic = "$RPC/+/+/response";
+        private const string ResponseTopic = "$MQTTnet.RPC/+/+/response";
         private readonly ConcurrentDictionary<string, TaskCompletionSource<byte[]>> _waitingCalls = new ConcurrentDictionary<string, TaskCompletionSource<byte[]>>();
         private readonly IMqttClient _mqttClient;
         private bool _isEnabled;

Extensions/MQTTnet.Extensions.Rpc/SampleCCode.c

@@ -0,0 +1 @@
+

Frameworks/MQTTnet.NetStandard/Client/MqttClientExtensions.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using MQTTnet.Protocol;
 
 namespace MQTTnet.Client
 {
@@ -15,6 +16,14 @@ namespace MQTTnet.Client
             return client.SubscribeAsync(topicFilters.ToList());
         }
 
+        public static Task<IList<MqttSubscribeResult>> SubscribeAsync(this IMqttClient client, string topic, MqttQualityOfServiceLevel qualityOfServiceLevel)
+        {
+            if (client == null) throw new ArgumentNullException(nameof(client));
+            if (topic == null) throw new ArgumentNullException(nameof(topic));
+
+            return client.SubscribeAsync(new TopicFilterBuilder().WithTopic(topic).WithQualityOfServiceLevel(qualityOfServiceLevel).Build());
+        }
+
         public static Task UnsubscribeAsync(this IMqttClient client, params string[] topicFilters)
         {
             if (client == null) throw new ArgumentNullException(nameof(client));

Tests/MQTTnet.TestApp.UniversalWindows/MainPage.xaml

@@ -19,6 +19,8 @@
                 <StackPanel Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
                     <TextBlock>Server:</TextBlock>
                     <TextBox x:Name="Server"></TextBox>
+                    <TextBlock>Port:</TextBlock>
+                    <TextBox x:Name="Port" Text="1883"></TextBox>
                     <TextBlock>User:</TextBlock>
                     <TextBox x:Name="User"></TextBox>
                     <TextBlock>Password:</TextBlock>

Tests/MQTTnet.TestApp.UniversalWindows/MainPage.xaml.cs

@@ -78,6 +78,7 @@ namespace MQTTnet.TestApp.UniversalWindows
                 options.ChannelOptions = new MqttClientTcpOptions
                 {
                     Server = Server.Text,
+                    Port = int.Parse(Port.Text),
                     TlsOptions = tlsOptions
                 };
             }