fix(response): write response header specifications using the correct format

Author: Fresa

src/OpenAPI.WebApiGenerator/ApiGenerator.cs

@@ -88,7 +88,7 @@ private static void GenerateCode(SourceProductionContext context, (
             rootNamespace);
         httpRequestExtensionsGenerator.GenerateHttpRequestExtensionsClass().AddTo(context);
 
-        var httpResponseExtensionsGenerator = new HttpResponseExtensionsGenerator(rootNamespace);
+        var httpResponseExtensionsGenerator = new HttpResponseExtensionsGenerator(openApiVersion, rootNamespace);
         httpResponseExtensionsGenerator.GenerateHttpResponseExtensionsClass().AddTo(context);
 
         var apiConfigurationGenerator = new ApiConfigurationGenerator(rootNamespace);

src/OpenAPI.WebApiGenerator/CodeGeneration/HttpResponseExtensionsGenerator.cs

@@ -1,30 +1,45 @@
-using OpenAPI.WebApiGenerator.Extensions;
+using System;
+using System.IO;
+using Microsoft.OpenApi;
+using OpenAPI.WebApiGenerator.Extensions;
 
 namespace OpenAPI.WebApiGenerator.CodeGeneration;
 
 internal sealed class HttpResponseExtensionsGenerator(
+    OpenApiSpecVersion openApiVersion,
     string @namespace)
 {
     private const string HttpResponseExtensionsClassName = "HttpResponseExtensions";
     public string Namespace => @namespace;
 
-    internal string CreateWriteHeaderInvocation(
-        string responseVariableName, 
-        string headerSpecificationAsJson,
-        string headerName,
-        string headerValueVariableName,
-        bool isRequired)
+    internal string GetResponseHeaderSpecificationAsJson(
+        IOpenApiHeader header, 
+        string name)
     {
-        return
-            $""""
-            {responseVariableName}.WriteResponseHeader(
-                """
-                {headerSpecificationAsJson.Indent(4)}
-                """,
-                "{headerName}",
-                {headerValueVariableName},
-                {isRequired.ToString().ToLowerInvariant()})
-            """";
+        using var textWriter = new StringWriter();
+        var jsonWriter = new OpenApiJsonWriter(textWriter, new OpenApiJsonWriterSettings
+        {
+            InlineLocalReferences = true
+        });
+        Action<IOpenApiWriter> serialize = openApiVersion switch
+        {
+            OpenApiSpecVersion.OpenApi3_1 => header.SerializeAsV31,
+            OpenApiSpecVersion.OpenApi3_0 => header.SerializeAsV3,
+            OpenApiSpecVersion.OpenApi2_0 => header.SerializeAsV2,
+            _ => throw new NotSupportedException(
+                $"OpenAPI version {Enum.GetName(typeof(OpenApiSpecVersion), openApiVersion)} not supported")
+        };
+        serialize(jsonWriter);
+        textWriter.Flush();
+
+        // Response header specification is a subset of the parameter specification, so we add the missing properties to be able to use the parameter value parser 
+        return 
+            $$"""
+              {
+                "name": "{{name}}",
+                "in": "header",
+                {{textWriter.GetStringBuilder().ToString().TrimStart('{').TrimStart()}} 
+              """;
     }
 
     internal string CreateWriteBodyInvocation(

src/OpenAPI.WebApiGenerator/CodeGeneration/ResponseHeaderGenerator.cs

@@ -1,6 +1,4 @@
-using System.IO;
-using System.Linq;
-using Corvus.Json.CodeGeneration;
+using Corvus.Json.CodeGeneration;
 using Corvus.Json.CodeGeneration.CSharp;
 using Microsoft.OpenApi;
 using OpenAPI.WebApiGenerator.Extensions;
@@ -29,28 +27,16 @@ internal string GenerateProperty() =>
 
     internal string GenerateWriteDirective(string responseVariableName)
     {
-        using var textWriter = new StringWriter();
-        var jsonWriter = new OpenApiJsonWriter(textWriter, new OpenApiJsonWriterSettings
-        {
-            InlineLocalReferences = true
-        });
-        header.SerializeAsV2(jsonWriter);
-        textWriter.Flush();
-
-        // Response header specification is a subset of the parameter specification, so we add the missing properties to be able to use the parameter value parser 
-        var headerSpecificationAsJson = 
-            $$"""
-              {
-                "name": "{{name}}",
-                "in": "header",
-                {{textWriter.GetStringBuilder().ToString().TrimStart('{').TrimStart()}} 
-              """;
-        
-        return $"{httpResponseExtensionsGenerator.CreateWriteHeaderInvocation(
-            responseVariableName,
-            headerSpecificationAsJson,
-            name,
-            $"Headers.{_propertyName}",
-            header.Required)};";
+        var headerSpecificationAsJson = httpResponseExtensionsGenerator.GetResponseHeaderSpecificationAsJson(header, name);
+        return
+            $""""
+             {responseVariableName}.WriteResponseHeader(
+                 """
+                 {headerSpecificationAsJson.Indent(4).TrimStart()}
+                 """,
+                 "{name}",
+                 Headers.{_propertyName},
+                 {header.Required.ToString().ToLowerInvariant()});
+             """";
     }
 }