[WIP]Update Client.Class.liquid - issue 2736. AllowEmptyInputInBodyMo…

…delBinding (RicoSuter#3195)

* Update Client.Class.liquid - issue 2736. Fix for AllowEmptyInputInBodyModelBinding

* Update Client.Class.liquid

Co-authored-by: Vitaly Melnik <[email protected]>
Co-authored-by: Rico Suter <[email protected]>

src/NSwag.CodeGeneration.CSharp.Tests/AllowNullableBodyParametersTests.cs

@@ -0,0 +1,77 @@
+using System.ComponentModel.DataAnnotations;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using NSwag.Generation.WebApi;
+using Xunit;
+
+namespace NSwag.CodeGeneration.CSharp.Tests
+{
+    public class AllowNullableBodyParametersTests
+    {
+        [Fact]
+        public async Task TestNullableBodyWithAllowNullableBodyParameters()
+        {
+            //// Arrange
+            var generator = await GenerateCode(true);
+
+            //// Act
+            var code = generator.GenerateFile();
+
+            //// Assert
+            Assert.False(HasGuardForBodyIsNull(code));
+        }
+
+        [Fact]
+        public async Task TestNullableBodyWithoutAllowNullableBodyParameters()
+        {
+            //// Arrange
+            var generator = await GenerateCode(false);
+
+            //// Act
+            var code = generator.GenerateFile();
+
+            //// Assert
+            Assert.True(HasGuardForBodyIsNull(code));
+        }
+
+        private static async Task<CSharpClientGenerator> GenerateCode(bool allowNullableBodyParameters)
+        {
+            var swaggerGenerator = new WebApiOpenApiDocumentGenerator(new WebApiOpenApiDocumentGeneratorSettings
+            {
+                AllowNullableBodyParameters = allowNullableBodyParameters
+            });
+            var document = await swaggerGenerator.GenerateForControllerAsync<TestController>();
+
+            var generator = new CSharpClientGenerator(document, new CSharpClientGeneratorSettings
+            {
+                InjectHttpClient = false,
+                ConfigurationClass = "MyConfig",
+                ClientBaseClass = "MyBaseClass"
+            });
+            return generator;
+        }
+
+        private static bool HasGuardForBodyIsNull(string code)
+        {
+            return code.Contains("throw new System.ArgumentNullException");
+        }
+
+        public class TestController : Controller
+        {
+            [Route("Foo")]
+            public string Foo([FromBody] [Required] T requiredBody)
+            {
+                return string.Empty;
+            }
+
+            [Route("Bar")]
+            public void Bar([FromBody] T notRequiredBody)
+            {
+            }
+
+            public class T
+            {
+            }
+        }
+    }
+}

src/NSwag.CodeGeneration.CSharp/Templates/Client.Class.liquid

@@ -124,7 +124,7 @@
 
 {%         endif -%}
 {%     endfor -%}
-{%     if operation.HasContent and operation.ContentParameter.IsRequired -%}
+{%     if operation.HasContent and operation.ContentParameter.IsNullable != true -%}
         if ({{ operation.ContentParameter.VariableName }} == null)
             throw new System.ArgumentNullException("{{ operation.ContentParameter.VariableName }}");