[csharp] Add useVirtualForHooks option (#20705)

Author: sbward

modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConstants.java

@@ -286,6 +286,9 @@ public static enum ENUM_PROPERTY_NAMING_TYPE {camelCase, PascalCase, snake_case,
     public static final String SUPPORTS_ASYNC = "supportsAsync";
     public static final String SUPPORTS_ASYNC_DESC = "Generate code that supports async operations.";
 
+    public static final String USE_VIRTUAL_FOR_HOOKS = "useVirtualForHooks";
+    public static final String USE_VIRTUAL_FOR_HOOKS_DESC = "Generate code that exposes public virtual hooks on ApiClient to customize low-level HTTP requests.";
+
     public static final String EXCLUDE_TESTS = "excludeTests";
     public static final String EXCLUDE_TESTS_DESC = "Specifies that no tests are to be generated.";
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java

@@ -108,6 +108,7 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
 
     protected boolean supportsRetry = Boolean.TRUE;
     protected boolean supportsAsync = Boolean.TRUE;
+    protected boolean useVirtualForHooks = Boolean.FALSE;
     protected boolean netStandard = Boolean.FALSE;
     protected boolean supportsFileParameters = Boolean.TRUE;
     protected boolean supportsDateOnly = Boolean.FALSE;
@@ -853,6 +854,7 @@ public void processOpts() {
         syncBooleanProperty(additionalProperties, CodegenConstants.EQUATABLE, this::setEquatable, this.equatable);
         syncBooleanProperty(additionalProperties, CodegenConstants.VALIDATABLE, this::setValidatable, this.validatable);
         syncBooleanProperty(additionalProperties, CodegenConstants.SUPPORTS_ASYNC, this::setSupportsAsync, this.supportsAsync);
+        syncBooleanProperty(additionalProperties, CodegenConstants.USE_VIRTUAL_FOR_HOOKS, this::setUseVirtualForHooks, this.useVirtualForHooks);
         syncBooleanProperty(additionalProperties, SUPPORTS_RETRY, this::setSupportsRetry, this.supportsRetry);
         syncBooleanProperty(additionalProperties, CodegenConstants.OPTIONAL_METHOD_ARGUMENT, this::setOptionalMethodArgumentFlag, optionalMethodArgumentFlag);
         syncBooleanProperty(additionalProperties, CodegenConstants.NON_PUBLIC_API, this::setNonPublicApi, isNonPublicApi());
@@ -1216,6 +1218,10 @@ public void setSupportsAsync(Boolean supportsAsync) {
         this.supportsAsync = supportsAsync;
     }
 
+    public void setUseVirtualForHooks(Boolean useVirtualForHooks) {
+        this.useVirtualForHooks = useVirtualForHooks;
+    }
+
     public void setSupportsFileParameters(Boolean supportsFileParameters) {
         this.supportsFileParameters = supportsFileParameters;
     }

modules/openapi-generator/src/main/resources/csharp/ApiClient.mustache

@@ -191,14 +191,14 @@ namespace {{packageName}}.Client
         /// Allows for extending request processing for <see cref="ApiClient"/> generated code.
         /// </summary>
         /// <param name="request">The RestSharp request object</param>
-        partial void InterceptRequest(RestRequest request);
+        {{#useVirtualForHooks}}public virtual{{/useVirtualForHooks}}{{^useVirtualForHooks}}partial{{/useVirtualForHooks}} void InterceptRequest(RestRequest request){{#useVirtualForHooks}} { }{{/useVirtualForHooks}}{{^useVirtualForHooks}};{{/useVirtualForHooks}}
 
         /// <summary>
         /// Allows for extending response processing for <see cref="ApiClient"/> generated code.
         /// </summary>
         /// <param name="request">The RestSharp request object</param>
         /// <param name="response">The RestSharp response object</param>
-        partial void InterceptResponse(RestRequest request, RestResponse response);
+        {{#useVirtualForHooks}}public virtual{{/useVirtualForHooks}}{{^useVirtualForHooks}}partial{{/useVirtualForHooks}} void InterceptResponse(RestRequest request, RestResponse response){{#useVirtualForHooks}} { }{{/useVirtualForHooks}}{{^useVirtualForHooks}};{{/useVirtualForHooks}}
 
         /// <summary>
         /// Initializes a new instance of the <see cref="ApiClient" />, defaulting to the global configurations' base url.

modules/openapi-generator/src/main/resources/csharp/libraries/httpclient/ApiClient.mustache

@@ -419,8 +419,8 @@ namespace {{packageName}}.Client
             return request;
         }
 
-        partial void InterceptRequest(HttpRequestMessage req);
-        partial void InterceptResponse(HttpRequestMessage req, HttpResponseMessage response);
+        {{#useVirtualForHooks}}public virtual{{/useVirtualForHooks}}{{^useVirtualForHooks}}partial{{/useVirtualForHooks}} void InterceptRequest(HttpRequestMessage req){{#useVirtualForHooks}} { }{{/useVirtualForHooks}}{{^useVirtualForHooks}};{{/useVirtualForHooks}}
+        {{#useVirtualForHooks}}public virtual{{/useVirtualForHooks}}{{^useVirtualForHooks}}partial{{/useVirtualForHooks}} void InterceptResponse(HttpRequestMessage req, HttpResponseMessage response){{#useVirtualForHooks}} { }{{/useVirtualForHooks}}{{^useVirtualForHooks}};{{/useVirtualForHooks}}
 
         private async Task<ApiResponse<T>> ToApiResponse<T>(HttpResponseMessage response, object responseData, Uri uri)
         {