added support for basic async APIs (Azure#46974)

* added support for basic async APIs

* PR feedback

* removed dependency on deprecated package

Author: KrzysztofCwalina

sdk/provisioning/Azure.Provisioning.CloudMachine/src/Tsp/TypeSpecWriter.cs

@@ -5,6 +5,7 @@
 using System.IO;
 using System.Net;
 using System.Reflection;
+using System.Threading.Tasks;
 
 namespace System.ClientModel.TypeSpec;
 public static class TypeSpecWriter
@@ -104,7 +105,9 @@ private static void WriteOperation(StreamWriter writer, MethodInfo method, HashS
     {
         string httpVerb = ReadHttpVerb(method);
 
-        writer.Write($"{httpVerb} @route(\"{ToCamel(method.Name)}\") {method.Name}(");
+        var methodName = method.Name;
+        if (methodName.EndsWith("Async")) methodName = methodName.Substring(0, methodName.Length - "Async".Length);
+        writer.Write($"{httpVerb} @route(\"{ToCamel(methodName)}\") {methodName}(");
 
         bool first = true;
         foreach (var parameter in method.GetParameters())
@@ -136,11 +139,16 @@ private static void WriteOperation(StreamWriter writer, MethodInfo method, HashS
         }
         writer.WriteLine(") : {");
         writer.WriteLine($"    @statusCode statusCode: 200;");
-        if (method.ReflectedType != typeof(void))
-            writer.WriteLine($"    @body response : {method.ReturnType.ToTspType()};");
+
+        var returnType = method.ReturnType;
+        if (returnType == typeof(Task)) returnType = typeof(void);
+        else if (returnType.IsGenericType && returnType.GetGenericTypeDefinition() == typeof(Task<>))
+            returnType = returnType.GetGenericArguments()[0];
+
+        writer.WriteLine($"    @body response : {returnType.ToTspType()};");
         writer.WriteLine("  };");
-        if (method.ReturnType.IsModel())
-            models.Add(method.ReturnType);
+        if (returnType.IsModel())
+            models.Add(returnType);
     }
 
     private static string ReadParameterLocation(ParameterInfo parameter)

sdk/provisioning/Azure.Provisioning.CloudMachine/tests/Azure.Provisioning.CloudMachine.Tests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <LangVersion>12</LangVersion>
   </PropertyGroup>

sdk/provisioning/Azure.Provisioning.CloudMachine/tests/TdkTests.cs

@@ -0,0 +1,67 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+#nullable enable
+
+using System;
+using System.ClientModel.TypeSpec;
+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using NUnit.Framework;
+
+namespace Azure.CloudMachine.Tests;
+
+public class TdkTests
+{
+    [Test]
+    public void GenerateIAssistantService()
+    {
+        MemoryStream stream = new();
+        TypeSpecWriter.WriteServer<IAssistantService>(stream);
+        stream.Position = 0;
+
+        BinaryData data = BinaryData.FromStream(stream);
+        Assert.AreEqual(IAssistantServiceTsp, data.ToString());
+    }
+
+    private static string IAssistantServiceTsp =
+    """
+    import "@typespec/http";
+    import "@typespec/rest";
+    import "@azure-tools/typespec-client-generator-core";
+
+    @service({
+      title: "AssistantService",
+    })
+
+    namespace Azure.CloudMachine.Tests;
+
+    using TypeSpec.Http;
+    using TypeSpec.Rest;
+    using Azure.ClientGenerator.Core;
+
+    @client interface AssistantServiceClient {
+      @put @route("upload") Upload(@header contentType: "application/octet-stream", @body document: bytes) : {
+        @statusCode statusCode: 200;
+        @body response : void;
+      };
+      @get @route("send") Send(@query message: string) : {
+        @statusCode statusCode: 200;
+        @body response : string;
+      };
+    }
+
+
+    """;
+}
+
+internal interface IAssistantService
+{
+    [HttpPut]
+    Task UploadAsync(HttpRequest document);
+    Task<string> SendAsync([FromQuery] string message);
+}
+
+internal class FromQueryAttribute : Attribute { }
+internal class HttpPutAttribute : Attribute { }