Merge pull request #5 from seikosantana/from-payload_parameter

[FromPayload] Support

Author: maikebing

ExampleServer/MqttControllers/ViewModelController.cs

@@ -0,0 +1,29 @@
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using MQTTnet.AspNetCore.Routing;
+using MQTTnet.AspNetCore.Routing.Attributes;
+
+namespace ExampleServer.MqttControllers;
+
+[MqttController]
+public class ViewModelController: MqttBaseController
+{
+    private ILogger<ViewModelController> Logger { get; }
+    
+    public ViewModelController(ILogger<ViewModelController> logger)
+    {
+        Logger = logger;
+    }
+
+    [MqttRoute("viewmodel/{sender}")]
+    public Task DeserializeViewModel(string sender, [FromPayload] SamplePayload payload)
+    {
+        Logger.LogInformation("{Sender} says {Message}", sender, payload.Message);
+        return Accepted();
+    }
+}
+
+public class SamplePayload
+{
+    public string Message { get; set; }
+}

ExampleServer/Startup.cs

@@ -1,4 +1,5 @@
 using System.Linq;
+using System.Text.Json;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
@@ -29,6 +30,10 @@ public void ConfigureServices(IServiceCollection services)
 
             // Identify and build routes for the current assembly
             services.AddMqttControllers();
+            
+            // Use specific deserialization option for MQTT payload deserialization
+            services.AddMqttDefaultJsonOptions(new JsonSerializerOptions(JsonSerializerDefaults.Web));
+            
             services
                 .AddHostedMqttServerWithServices(s =>
                 {

Source/Attributes/FromPayloadAttribute.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Text.Json;
+
+namespace MQTTnet.AspNetCore.Routing.Attributes;
+
+[AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = true)]
+public class FromPayloadAttribute : Attribute
+{
+    public FromPayloadAttribute()
+    {
+        
+    }
+}

Source/Extensions/ServiceCollectionExtensions.cs

@@ -6,6 +6,7 @@
 using System;
 using System.Reflection;
 using System.Runtime.CompilerServices;
+using System.Text.Json;
 
 // This is needed to make internal classes visible to UnitTesting projects
 [assembly: InternalsVisibleTo("MQTTnet.AspNetCore.Routing.Tests, PublicKey=00240000048000009" +
@@ -38,6 +39,13 @@ public static IServiceCollection AddMqttControllers(this IServiceCollection serv
             return services;
         }
 
+        public static IServiceCollection AddMqttDefaultJsonOptions(this IServiceCollection services,
+            JsonSerializerOptions options)
+        {
+            services.AddSingleton(new MqttDefaultJsonOptions(options));
+            return services;
+        }
+
         public static void WithAttributeRouting(this MqttServer server, IServiceProvider svcProvider, bool allowUnmatchedRoutes = false)
         {
             var router = svcProvider.GetRequiredService<MqttRouter>();

Source/Routing/MqttDefaultJsonOptions.cs

@@ -0,0 +1,13 @@
+using System.Text.Json;
+
+namespace MQTTnet.AspNetCore.Routing;
+
+public class MqttDefaultJsonOptions
+{
+    public JsonSerializerOptions SerializerOptions { get; }
+
+    public MqttDefaultJsonOptions(JsonSerializerOptions options)
+    {
+        SerializerOptions = options;
+    }
+}

Source/Routing/MqttRouter.cs

@@ -8,6 +8,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
+using System.Text.Json;
 using System.Threading.Tasks;
 
 #nullable enable
@@ -122,7 +123,10 @@ internal async Task OnIncomingApplicationMessage(IServiceProvider svcProvider, I
 
                         try
                         {
-                            paramArray = parameters.Select(p => MatchParameterOrThrow(p, routeContext.Parameters)).ToArray();
+                            paramArray = parameters.Select(p =>
+                                    MatchParameterOrThrow(p, routeContext.Parameters, controllerContext, svcProvider)
+                                )
+                                .ToArray();
 
                             await HandlerInvoker(routeContext.Handler, classInstance, paramArray).ConfigureAwait(false);
                         }
@@ -174,8 +178,20 @@ private static Task HandlerInvoker(MethodInfo method, object instance, object?[]
             throw new InvalidOperationException($"Unsupported Action return type \"{method.ReturnType}\" on method {method.DeclaringType.FullName}.{method.Name}. Only void and {nameof(Task)} are allowed.");
         }
 
-        private static object? MatchParameterOrThrow(ParameterInfo param, IReadOnlyDictionary<string, object> availableParmeters)
+        private static object? MatchParameterOrThrow(ParameterInfo param,
+            IReadOnlyDictionary<string, object> availableParmeters, MqttControllerContext controllerContext,
+            IServiceProvider serviceProvider)
         {
+            if (param.IsDefined(typeof(FromPayloadAttribute), false))
+            {
+                JsonSerializerOptions? defaultOptions =
+                    serviceProvider.GetService<MqttDefaultJsonOptions>()?.SerializerOptions;
+                return JsonSerializer.Deserialize(controllerContext.MqttContext.ApplicationMessage.Payload,
+                    param.ParameterType,
+                    defaultOptions
+                );
+            }
+
             if (!availableParmeters.TryGetValue(param.Name, out object? value))
             {
                 if (param.IsOptional)