[JAVA-SPRING] Convert byte[] to String for operation params [QueryParam; PathParam; HeaderParam; CookieParam; FormParam]

.github/workflows/samples-spring.yaml

@@ -44,6 +44,8 @@ jobs:
           - samples/server/petstore/spring-boot-nullable-set
           - samples/server/petstore/spring-boot-defaultInterface-unhandledExcp
           - samples/server/petstore/springboot
+          - samples/server/petstore/springboot-byte-format-edge-cases
+          - samples/server/petstore/springboot-byte-format-edge-cases-reactive
           - samples/server/petstore/springboot-beanvalidation
           - samples/server/petstore/springboot-builtin-validation
           - samples/server/petstore/springboot-delegate

bin/configs/spring-boot-byte-format-edge-cases-reactive.yaml

@@ -0,0 +1,11 @@
+generatorName: spring
+outputDir: samples/server/petstore/springboot-byte-format-edge-cases-reactive
+inputSpec: modules/openapi-generator/src/test/resources/3_0/spring/byte-format-edge-cases.yaml
+templateDir: modules/openapi-generator/src/main/resources/JavaSpring
+additionalProperties:
+  artifactId: springboot
+  snapshotVersion: "true"
+  hideGenerationTimestamp: "true"
+  reactive: true
+  interfaceOnly: "true"
+  requestMappingMode: "none"

bin/configs/spring-boot-byte-format-edge-cases.yaml

@@ -0,0 +1,10 @@
+generatorName: spring
+outputDir: samples/server/petstore/springboot-byte-format-edge-cases
+inputSpec: modules/openapi-generator/src/test/resources/3_0/spring/byte-format-edge-cases.yaml
+templateDir: modules/openapi-generator/src/main/resources/JavaSpring
+additionalProperties:
+  artifactId: springboot
+  snapshotVersion: "true"
+  hideGenerationTimestamp: "true"
+  interfaceOnly: "true"
+  requestMappingMode: "none"

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

@@ -647,6 +647,27 @@ public void processOpts() {
 
         additionalProperties.put("lambdaSplitString", new SplitStringLambda());
 
+        // Lambda to add type comment only if actual type differs from implemented type
+        // Format: "implementedType|actualType" -> " /* actualType */" or ""
+        additionalProperties.put("lambdaTypeComment", (Mustache.Lambda) (fragment, writer) -> {
+            String input = fragment.execute().trim();
+            String[] parts = input.split("\\|", 2);
+            if (parts.length == 2) {
+                String implementedType = parts[0].trim();
+                String actualType = parts[1].trim();
+
+                // Only add comment if types differ
+                if (!implementedType.equals(actualType)) {
+                    // Also check if implementedType is a collection of actualType (e.g., List<String> vs String)
+                    String expectedCollection = "List<" + actualType + ">";
+                    String expectedFlux = "Flux<" + actualType + ">";
+                    if (!implementedType.equals(expectedCollection) && !implementedType.equals(expectedFlux)) {
+                        writer.write(" /* " + actualType + " */");
+                    }
+                }
+            }
+        });
+
         // apiController: hide implementation behind undocumented flag to temporarily preserve code
         additionalProperties.put("_api_controller_impl_", false);
         // HEADS-UP: Do not add more template file after this block
@@ -798,6 +819,8 @@ public void setIsVoid(boolean isVoid) {
 
                 prepareVersioningParameters(ops);
                 handleImplicitHeaders(operation);
+                convertByteArrayParamsToStringType(operation);
+                markMultipartFormDataParameters(operation);
             }
             // The tag for the controller is the first tag of the first operation
             final CodegenOperation firstOperation = ops.get(0);
@@ -813,6 +836,64 @@ public void setIsVoid(boolean isVoid) {
         return objs;
     }
 
+    /**
+     * Converts parameters of type {@code byte[]} (i.e., OpenAPI {@code type: string, format: byte}) to {@code String}.
+     * <p>
+     * In OpenAPI, {@code type: string, format: byte} is a base64-encoded string. However, Spring does not automatically
+     * decode base64-encoded request parameters into {@code byte[]} for query, path, header, cookie, or form parameters.
+     * Therefore, these parameters are mapped to {@code String} to avoid incorrect type handling and to ensure the
+     * application receives the raw base64 string as provided by the client.
+     * </p>
+     *
+     * @param operation the codegen operation whose parameters will be checked and converted if necessary
+     **/
+    private void convertByteArrayParamsToStringType(CodegenOperation operation) {
+        var convertedParams = operation.allParams.stream()
+                .filter(CodegenParameter::getIsByteArray)
+                .filter(param -> param.isQueryParam || param.isPathParam || param.isHeaderParam || param.isCookieParam || param.isFormParam)
+                .peek(param -> param.dataType = "String")
+                .collect(Collectors.toList());
+        LOGGER.info("Converted parameters [{}] from byte[] to String in operation [{}]", convertedParams.stream().map(param -> param.paramName).collect(Collectors.toList()), operation.operationId);
+    }
+
+    /**
+     * Marks form parameters that are in multipart/form-data operations for special handling in reactive mode.
+     * <p>
+     * In reactive Spring WebFlux, multipart/form-data parameters must use @RequestPart instead of @RequestParam,
+     * and non-model parameters (primitives, enums, strings) must be received as String or Flux&lt;String&gt; and
+     * converted manually in the implementation.
+     * </p>
+     *
+     * @param operation the codegen operation whose parameters will be marked if necessary
+     **/
+    private void markMultipartFormDataParameters(CodegenOperation operation) {
+        if (!reactive) {
+            return; // Only applies to reactive mode
+        }
+
+        // Check if this operation consumes multipart/form-data
+        boolean isMultipartFormData = false;
+        if (operation.hasConsumes) {
+            for (Map<String, String> consume : operation.consumes) {
+                if ("multipart/form-data".equals(consume.get("mediaType"))) {
+                    isMultipartFormData = true;
+                    break;
+                }
+            }
+        }
+
+        if (!isMultipartFormData) {
+            return;
+        }
+
+        // Mark all form parameters as multipart form data
+        for (CodegenParameter param : operation.allParams) {
+            if (param.isFormParam) {
+                param.vendorExtensions.put("x-isMultipartFormData", true);
+            }
+        }
+    }
+
     private interface DataTypeAssigner {
         void setReturnType(String returnType);
 

modules/openapi-generator/src/main/resources/JavaSpring/cookieParams.mustache

@@ -1 +1 @@
-{{#isCookieParam}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{>paramDoc}} @CookieValue(name = "{{baseName}}"{{^required}}, required = false{{/required}}{{#defaultValue}}, defaultValue = "{{{.}}}"{{/defaultValue}}){{>dateTimeParam}} {{>nullableAnnotation}}{{>optionalDataType}} {{paramName}}{{/isCookieParam}}
+{{#isCookieParam}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{>paramDoc}} @CookieValue(name = "{{baseName}}"{{^required}}, required = false{{/required}}{{#defaultValue}}, defaultValue = "{{{.}}}"{{/defaultValue}}){{>dateTimeParam}} {{>nullableAnnotation}}{{>optionalDataType}} {{paramName}}{{#isByteArray}} /* base64 encoded binary */{{/isByteArray}}{{/isCookieParam}}

modules/openapi-generator/src/main/resources/JavaSpring/formParams.mustache

@@ -1 +1 @@
-{{#isFormParam}}{{^isFile}}{{>paramDoc}}{{#useBeanValidation}} {{>beanValidationBodyParams}}@Valid{{/useBeanValidation}} {{#isModel}}@RequestPart{{/isModel}}{{^isModel}}{{#isArray}}@RequestPart{{/isArray}}{{^isArray}}{{#reactive}}@RequestPart{{/reactive}}{{^reactive}}@RequestParam{{/reactive}}{{/isArray}}{{/isModel}}(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}){{>dateTimeParam}} {{^required}}{{#useOptional}}Optional<{{/useOptional}}{{/required}}{{{dataType}}}{{^required}}{{#useOptional}}>{{/useOptional}}{{/required}} {{paramName}}{{/isFile}}{{#isFile}}{{>paramDoc}} @RequestPart(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}) {{#reactive}}{{#isArray}}Flux<{{/isArray}}Part{{#isArray}}>{{/isArray}}{{/reactive}}{{^reactive}}{{#isArray}}List<{{/isArray}}MultipartFile{{#isArray}}>{{/isArray}}{{/reactive}} {{paramName}}{{/isFile}}{{/isFormParam}}
+{{#isFormParam}}{{^isFile}}{{>paramDoc}}{{#useBeanValidation}} {{>beanValidationBodyParams}}@Valid{{/useBeanValidation}} {{#isModel}}@RequestPart{{/isModel}}{{^isModel}}{{#isArray}}{{#items.isModel}}@RequestPart{{/items.isModel}}{{^items.isModel}}{{#reactive}}{{#vendorExtensions.x-isMultipartFormData}}@RequestPart{{/vendorExtensions.x-isMultipartFormData}}{{^vendorExtensions.x-isMultipartFormData}}@RequestParam{{/vendorExtensions.x-isMultipartFormData}}{{/reactive}}{{^reactive}}@RequestParam{{/reactive}}{{/items.isModel}}{{/isArray}}{{^isArray}}{{#reactive}}{{#vendorExtensions.x-isMultipartFormData}}@RequestPart{{/vendorExtensions.x-isMultipartFormData}}{{^vendorExtensions.x-isMultipartFormData}}@RequestParam{{/vendorExtensions.x-isMultipartFormData}}{{/reactive}}{{^reactive}}@RequestParam{{/reactive}}{{/isArray}}{{/isModel}}(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}){{>dateTimeParam}} {{^required}}{{#useOptional}}Optional<{{/useOptional}}{{/required}}{{#reactive}}{{#vendorExtensions.x-isMultipartFormData}}{{#isModel}}{{{dataType}}}{{/isModel}}{{^isModel}}{{#isArray}}{{#items.isModel}}{{{dataType}}}{{/items.isModel}}{{^items.isModel}}Flux<String>{{#lambdaTypeComment}}Flux<String>|{{{dataType}}}{{/lambdaTypeComment}}{{/items.isModel}}{{/isArray}}{{^isArray}}String{{#lambdaTypeComment}}String|{{{dataType}}}{{/lambdaTypeComment}}{{/isArray}}{{/isModel}}{{/vendorExtensions.x-isMultipartFormData}}{{^vendorExtensions.x-isMultipartFormData}}{{{dataType}}}{{/vendorExtensions.x-isMultipartFormData}}{{/reactive}}{{^reactive}}{{{dataType}}}{{/reactive}}{{^required}}{{#useOptional}}>{{/useOptional}}{{/required}} {{paramName}}{{/isFile}}{{#isByteArray}} /* base64 encoded binary */{{/isByteArray}}{{#isFile}}{{>paramDoc}} @RequestPart(value = "{{baseName}}"{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}) {{#reactive}}{{#isArray}}Flux<{{/isArray}}Part{{#isArray}}>{{/isArray}}{{/reactive}}{{^reactive}}{{#isArray}}List<{{/isArray}}MultipartFile{{#isArray}}>{{/isArray}}{{/reactive}} {{paramName}}{{/isFile}}{{/isFormParam}}

modules/openapi-generator/src/main/resources/JavaSpring/headerParams.mustache

@@ -1 +1 @@
-{{#isHeaderParam}}{{#vendorExtensions.x-field-extra-annotation}}{{{.}}} {{/vendorExtensions.x-field-extra-annotation}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{>paramDoc}} @RequestHeader(value = "{{baseName}}", required = {{#required}}true{{/required}}{{^required}}false{{/required}}{{#defaultValue}}, defaultValue = "{{{.}}}"{{/defaultValue}}){{>dateTimeParam}} {{>nullableAnnotation}}{{>optionalDataType}} {{paramName}}{{/isHeaderParam}}
+{{#isHeaderParam}}{{#vendorExtensions.x-field-extra-annotation}}{{{.}}} {{/vendorExtensions.x-field-extra-annotation}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{>paramDoc}} @RequestHeader(value = "{{baseName}}", required = {{#required}}true{{/required}}{{^required}}false{{/required}}{{#defaultValue}}, defaultValue = "{{{.}}}"{{/defaultValue}}){{>dateTimeParam}} {{>nullableAnnotation}}{{>optionalDataType}} {{paramName}}{{#isByteArray}} /* base64 encoded binary */{{/isByteArray}}{{/isHeaderParam}}

modules/openapi-generator/src/main/resources/JavaSpring/pathParams.mustache

@@ -1 +1 @@
-{{#isPathParam}}{{#vendorExtensions.x-field-extra-annotation}}{{{.}}} {{/vendorExtensions.x-field-extra-annotation}}{{#useBeanValidation}}{{>beanValidationPathParams}}{{/useBeanValidation}}{{>paramDoc}} @PathVariable("{{baseName}}"){{>dateTimeParam}}{{#isDeprecated}} @Deprecated{{/isDeprecated}} {{>optionalDataType}} {{paramName}}{{/isPathParam}}
+{{#isPathParam}}{{#vendorExtensions.x-field-extra-annotation}}{{{.}}} {{/vendorExtensions.x-field-extra-annotation}}{{#useBeanValidation}}{{>beanValidationPathParams}}{{/useBeanValidation}}{{>paramDoc}} @PathVariable("{{baseName}}"){{>dateTimeParam}}{{#isDeprecated}} @Deprecated{{/isDeprecated}} {{>optionalDataType}} {{paramName}}{{#isByteArray}} /* base64 encoded binary */{{/isByteArray}}{{/isPathParam}}

modules/openapi-generator/src/main/resources/JavaSpring/queryParams.mustache

@@ -1 +1 @@
-{{#isQueryParam}}{{#vendorExtensions.x-field-extra-annotation}}{{{.}}} {{/vendorExtensions.x-field-extra-annotation}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{>paramDoc}}{{#useBeanValidation}} @Valid{{/useBeanValidation}}{{^isModel}} @RequestParam(value = {{#isMap}}""{{/isMap}}{{^isMap}}"{{baseName}}"{{/isMap}}{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}{{#defaultValue}}, defaultValue = "{{{.}}}"{{/defaultValue}}){{/isModel}}{{>dateTimeParam}}{{#isDeprecated}} @Deprecated{{/isDeprecated}} {{>nullableAnnotation}}{{>optionalDataType}} {{paramName}}{{/isQueryParam}}
+{{#isQueryParam}}{{#vendorExtensions.x-field-extra-annotation}}{{{.}}} {{/vendorExtensions.x-field-extra-annotation}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{>paramDoc}}{{#useBeanValidation}} @Valid{{/useBeanValidation}}{{^isModel}} @RequestParam(value = {{#isMap}}""{{/isMap}}{{^isMap}}"{{baseName}}"{{/isMap}}{{#required}}, required = true{{/required}}{{^required}}, required = false{{/required}}{{#defaultValue}}, defaultValue = "{{{.}}}"{{/defaultValue}}){{/isModel}}{{>dateTimeParam}}{{#isDeprecated}} @Deprecated{{/isDeprecated}} {{>nullableAnnotation}}{{>optionalDataType}} {{paramName}}{{#isByteArray}} /* base64 encoded binary */{{/isByteArray}}{{/isQueryParam}}

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java

@@ -2690,7 +2690,7 @@ public void testRestClientFormMultipart() {
                         + " files.stream().map(FileSystemResource::new).collect(Collectors.toList()));",
 
                 // mixed
-                "multipartMixed(@jakarta.annotation.Nonnull MultipartMixedStatus status, @jakarta.annotation.Nonnull File _file, @jakarta.annotation.Nullable MultipartMixedRequestMarker marker, @jakarta.annotation.Nullable List<MultipartMixedStatus> statusArray)",
+                "multipartMixed(@jakarta.annotation.Nonnull MultipartMixedStatus status, @jakarta.annotation.Nonnull File _file, @jakarta.annotation.Nullable MultipartMixedRequestMarker marker, @jakarta.annotation.Nullable List<MultipartMixedRequestMarker> markerArray, @jakarta.annotation.Nullable List<MultipartMixedStatus> statusArray)",
                 "formParams.add(\"file\", new FileSystemResource(_file));",
 
                 // single file
@@ -2720,7 +2720,7 @@ public void testRestClientWithUseAbstractionForFiles() {
                 "formParams.addAll(\"files\", files.stream().collect(Collectors.toList()));",
 
                 // mixed
-                "multipartMixed(@jakarta.annotation.Nonnull MultipartMixedStatus status, org.springframework.core.io.AbstractResource _file, @jakarta.annotation.Nullable MultipartMixedRequestMarker marker, @jakarta.annotation.Nullable List<MultipartMixedStatus> statusArray)",
+                "multipartMixed(@jakarta.annotation.Nonnull MultipartMixedStatus status, org.springframework.core.io.AbstractResource _file, @jakarta.annotation.Nullable MultipartMixedRequestMarker marker, @jakarta.annotation.Nullable List<MultipartMixedRequestMarker> markerArray, @jakarta.annotation.Nullable List<MultipartMixedStatus> statusArray)",
                 "formParams.add(\"file\", _file);",
 
                 // single file

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/assertions/PropertyAssert.java

@@ -26,6 +26,20 @@ public PropertyAssert withType(final String expectedType) {
         return this;
     }
 
+    public PropertyAssert isArray() {
+        Assertions.assertThat(actual.getCommonType().isArrayType())
+                .withFailMessage("Expected property %s to be array, but it was NOT", actual.getVariable(0).getNameAsString())
+                .isEqualTo(true);
+        return this;
+    }
+
+    public PropertyAssert isNotArray() {
+        Assertions.assertThat(actual.getCommonType().isArrayType())
+                .withFailMessage("Expected property %s NOT to be array, but it was", actual.getVariable(0).getNameAsString())
+                .isEqualTo(false);
+        return this;
+    }
+
     public PropertyAnnotationsAssert assertPropertyAnnotations() {
         return new PropertyAnnotationsAssert(this, actual.getAnnotations());
     }