[Bug][java-spring] Use Flux only for multipart-form-data file parameters with multiple file uploads (#21561)

* Use Flux only for multipart-form-data file parameters with multiple files * Update samples --------- Co-authored-by: Chris Gual <cgual@omnidian.com>
2025-12-08 14:36:12 +00:00 · 2025-07-28 03:28:53 -07:00
parent d69714f197
commit a60d3d4f81
16 changed files with 81 additions and 21 deletions
--- a/modules/openapi-generator/src/main/resources/JavaSpring/api.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/api.mustache
@@ -275,7 +275,7 @@ public interface {{classname}} {
    }

    // Override this method
-    {{#jdk8-default-interface}}default {{/jdk8-default-interface}} {{>responseType}} {{operationId}}({{#allParams}}{{^isFile}}{{^isBodyParam}}{{>optionalDataType}}{{/isBodyParam}}{{#isBodyParam}}{{^reactive}}{{>optionalDataType}}{{/reactive}}{{#reactive}}{{^isArray}}Mono<{{{dataType}}}>{{/isArray}}{{#isArray}}Flux<{{{baseType}}}>{{/isArray}}{{/reactive}}{{/isBodyParam}}{{/isFile}}{{#isFile}}{{#reactive}}Flux<Part>{{/reactive}}{{^reactive}}{{#isArray}}List<MultipartFile>{{/isArray}}{{^isArray}}MultipartFile{{/isArray}}{{/reactive}}{{/isFile}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}{{#reactive}}{{#hasParams}}, {{/hasParams}}{{#springFoxDocumentationProvider}}@ApiIgnore{{/springFoxDocumentationProvider}} final ServerWebExchange exchange{{/reactive}}{{#vendorExtensions.x-spring-paginated}}{{#hasParams}}, {{/hasParams}}{{^hasParams}}{{#reactive}}, {{/reactive}}{{/hasParams}}{{#springFoxDocumentationProvider}}@ApiIgnore{{/springFoxDocumentationProvider}}final Pageable pageable{{/vendorExtensions.x-spring-paginated}}){{#unhandledException}} throws Exception{{/unhandledException}} {
+    {{#jdk8-default-interface}}default {{/jdk8-default-interface}} {{>responseType}} {{operationId}}({{#allParams}}{{^isFile}}{{^isBodyParam}}{{>optionalDataType}}{{/isBodyParam}}{{#isBodyParam}}{{^reactive}}{{>optionalDataType}}{{/reactive}}{{#reactive}}{{^isArray}}Mono<{{{dataType}}}>{{/isArray}}{{#isArray}}Flux<{{{baseType}}}>{{/isArray}}{{/reactive}}{{/isBodyParam}}{{/isFile}}{{#isFile}}{{#reactive}}{{#isArray}}Flux<{{/isArray}}Part{{#isArray}}>{{/isArray}}{{/reactive}}{{^reactive}}{{#isArray}}List<{{/isArray}}MultipartFile{{#isArray}}>{{/isArray}}{{/reactive}}{{/isFile}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}{{#reactive}}{{#hasParams}}, {{/hasParams}}{{#springFoxDocumentationProvider}}@ApiIgnore{{/springFoxDocumentationProvider}} final ServerWebExchange exchange{{/reactive}}{{#vendorExtensions.x-spring-paginated}}{{#hasParams}}, {{/hasParams}}{{^hasParams}}{{#reactive}}, {{/reactive}}{{/hasParams}}{{#springFoxDocumentationProvider}}@ApiIgnore{{/springFoxDocumentationProvider}}final Pageable pageable{{/vendorExtensions.x-spring-paginated}}){{#unhandledException}} throws Exception{{/unhandledException}} {
        {{/delegate-method}}
        {{^isDelegate}}
        {{>methodBody}}{{! prevent indent}}
--- a/modules/openapi-generator/src/main/resources/JavaSpring/apiDelegate.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/apiDelegate.mustache
@@ -71,7 +71,7 @@ public interface {{classname}}Delegate {
    {{#isDeprecated}}
    @Deprecated
    {{/isDeprecated}}
-    {{#jdk8-default-interface}}default {{/jdk8-default-interface}}{{>responseType}} {{operationId}}({{#allParams}}{{^isFile}}{{^isBodyParam}}{{>optionalDataType}}{{/isBodyParam}}{{#isBodyParam}}{{^reactive}}{{>optionalDataType}}{{/reactive}}{{#reactive}}{{^isArray}}Mono<{{{dataType}}}>{{/isArray}}{{#isArray}}Flux<{{{baseType}}}>{{/isArray}}{{/reactive}}{{/isBodyParam}}{{/isFile}}{{#isFile}}{{#isArray}}List<{{/isArray}}{{#reactive}}Flux<Part>{{/reactive}}{{^reactive}}{{#isFormParam}}MultipartFile{{/isFormParam}}{{^isFormParam}}{{>optionalDataType}}{{/isFormParam}}{{/reactive}}{{#isArray}}>{{/isArray}}{{/isFile}} {{paramName}}{{^-last}},
+    {{#jdk8-default-interface}}default {{/jdk8-default-interface}}{{>responseType}} {{operationId}}({{#allParams}}{{^isFile}}{{^isBodyParam}}{{>optionalDataType}}{{/isBodyParam}}{{#isBodyParam}}{{^reactive}}{{>optionalDataType}}{{/reactive}}{{#reactive}}{{^isArray}}Mono<{{{dataType}}}>{{/isArray}}{{#isArray}}Flux<{{{baseType}}}>{{/isArray}}{{/reactive}}{{/isBodyParam}}{{/isFile}}{{#isFile}}{{#reactive}}{{#isArray}}Flux<{{/isArray}}Part{{#isArray}}>{{/isArray}}{{/reactive}}{{^reactive}}{{#isArray}}List<{{/isArray}}{{#isFormParam}}MultipartFile{{/isFormParam}}{{^isFormParam}}{{>optionalDataType}}{{/isFormParam}}{{#isArray}}>{{/isArray}}{{/reactive}}{{/isFile}} {{paramName}}{{^-last}},
        {{/-last}}{{/allParams}}{{#reactive}}{{#hasParams}},
        {{/hasParams}}ServerWebExchange exchange{{/reactive}}{{#vendorExtensions.x-spring-paginated}}{{#hasParams}}, {{/hasParams}}{{^hasParams}}{{#reactive}}, {{/reactive}}{{/hasParams}}final Pageable pageable{{/vendorExtensions.x-spring-paginated}}){{#unhandledException}} throws Exception{{/unhandledException}}{{^jdk8-default-interface}};{{/jdk8-default-interface}}{{#jdk8-default-interface}} {
        {{>methodBody}}{{! prevent indent}}
--- a/modules/openapi-generator/src/main/resources/JavaSpring/formParams.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/formParams.mustache
@@ -1 +1 @@
-{{#isFormParam}}{{^isFile}}{{>paramDoc}}{{#useBeanValidation}} @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}}) {{#isArray}}List<{{/isArray}}{{#reactive}}Flux<Part>{{/reactive}}{{^reactive}}MultipartFile{{/reactive}}{{#isArray}}>{{/isArray}} {{paramName}}{{/isFile}}{{/isFormParam}}
+{{#isFormParam}}{{^isFile}}{{>paramDoc}}{{#useBeanValidation}} @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}}
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java
@@ -733,6 +733,66 @@ public class SpringCodegenTest {
                .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"statusArray\"", "required", "false"));
    }

+    @Test
+    public void testReactiveMultipartBoot() throws IOException {
+        final SpringCodegen codegen = new SpringCodegen();
+        codegen.setLibrary("spring-boot");
+        codegen.setDelegatePattern(true);
+        codegen.additionalProperties().put(DOCUMENTATION_PROVIDER, "springfox");
+        codegen.additionalProperties().put(SpringCodegen.REACTIVE, "true");
+
+        final Map<String, File> files = generateFiles(codegen, "src/test/resources/3_0/form-multipart-binary-array.yaml");
+
+        // Check that the delegate handles the array
+        JavaFileAssert.assertThat(files.get("MultipartArrayApiDelegate.java"))
+            .assertMethod("multipartArray", "Flux<Part>", "ServerWebExchange")
+            .assertParameter("files").hasType("Flux<Part>");
+
+        // Check that the api handles the array
+        JavaFileAssert.assertThat(files.get("MultipartArrayApi.java"))
+            .assertMethod("multipartArray", "Flux<Part>", "ServerWebExchange")
+            .assertParameter("files").hasType("Flux<Part>")
+            .assertParameterAnnotations()
+            .containsWithNameAndAttributes("ApiParam", ImmutableMap.of("value", "\"Many files\""))
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"files\"", "required", "false"));
+
+        // UPDATE: the following test has been ignored due to https://github.com/OpenAPITools/openapi-generator/pull/11081/
+        // We will contact the contributor of the following test to see if the fix will break their use cases and
+        // how we can fix it accordingly.
+        //// Check that the delegate handles the single file
+        // final File multipartSingleApiDelegate = files.get("MultipartSingleApiDelegate.java");
+        // assertFileContains(multipartSingleApiDelegate.toPath(), "MultipartFile file");
+
+        // Check that the api handles the single file
+        JavaFileAssert.assertThat(files.get("MultipartSingleApi.java"))
+            .assertMethod("multipartSingle", "Part", "ServerWebExchange")
+            .assertParameter("file").hasType("Part")
+            .assertParameterAnnotations()
+            .containsWithNameAndAttributes("ApiParam", ImmutableMap.of("value", "\"One file\""))
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"file\"", "required", "false"));
+
+        // Check that api validates mixed multipart request
+        JavaFileAssert.assertThat(files.get("MultipartMixedApi.java"))
+            .assertMethod("multipartMixed", "MultipartMixedStatus", "Part", "MultipartMixedRequestMarker", "List<MultipartMixedStatus>", "ServerWebExchange")
+            .assertParameter("status").hasType("MultipartMixedStatus")
+            .assertParameterAnnotations()
+            .containsWithName("Valid")
+            .containsWithNameAndAttributes("ApiParam", ImmutableMap.of("value", "\"\""))
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"status\"", "required", "true"))
+            .toParameter().toMethod()
+            .assertParameter("file").hasType("Part")
+            .assertParameterAnnotations()
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"file\"", "required", "true"))
+            .toParameter().toMethod()
+            .assertParameter("marker").hasType("MultipartMixedRequestMarker")
+            .assertParameterAnnotations()
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"marker\"", "required", "false"))
+            .toParameter().toMethod()
+            .assertParameter("statusArray").hasType("List<MultipartMixedStatus>")
+            .assertParameterAnnotations()
+            .containsWithNameAndAttributes("RequestPart", ImmutableMap.of("value", "\"statusArray\"", "required", "false"));
+    }
+
    @Test
    public void testAdditionalProperties_issue1466() throws IOException {
        final SpringCodegen codegen = new SpringCodegen();
--- a/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/api/FakeApi.java
@@ -226,7 +226,7 @@ public interface FakeApi {
         @RequestPart(value = "int64", required = false) Long int64,
         @RequestPart(value = "float", required = false) Float _float,
         @RequestPart(value = "string", required = false) String string,
-         @RequestPart(value = "binary", required = false) Flux<Part> binary,
+         @RequestPart(value = "binary", required = false) Part binary,
         @RequestPart(value = "date", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date,
         @RequestPart(value = "dateTime", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) OffsetDateTime dateTime,
         @RequestPart(value = "password", required = false) String password,
--- a/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/api/PetApi.java
+++ b/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/api/PetApi.java
@@ -210,7 +210,7 @@ public interface PetApi {
    Mono<ModelApiResponse> uploadFile(
         @PathVariable("petId") Long petId,
         @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata,
-         @RequestPart(value = "file", required = false) Flux<Part> file
+         @RequestPart(value = "file", required = false) Part file
    );


@@ -232,7 +232,7 @@ public interface PetApi {
    )
    Mono<ModelApiResponse> uploadFileWithRequiredFile(
         @PathVariable("petId") Long petId,
-         @RequestPart(value = "requiredFile", required = true) Flux<Part> requiredFile,
+         @RequestPart(value = "requiredFile", required = true) Part requiredFile,
         @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata
    );

--- a/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/api/FakeApi.java
@@ -217,7 +217,7 @@ public interface FakeApi {
         @RequestPart(value = "int64", required = false) Long int64,
         @RequestPart(value = "float", required = false) Float _float,
         @RequestPart(value = "string", required = false) String string,
-         @RequestPart(value = "binary", required = false) Flux<Part> binary,
+         @RequestPart(value = "binary", required = false) Part binary,
         @RequestPart(value = "date", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date,
         @RequestPart(value = "dateTime", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) OffsetDateTime dateTime,
         @RequestPart(value = "password", required = false) String password,
--- a/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/api/PetApi.java
+++ b/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/api/PetApi.java
@@ -201,7 +201,7 @@ public interface PetApi {
    Mono<ResponseEntity<ModelApiResponse>> uploadFile(
         @PathVariable("petId") Long petId,
         @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata,
-         @RequestPart(value = "file", required = false) Flux<Part> file
+         @RequestPart(value = "file", required = false) Part file
    );


@@ -222,7 +222,7 @@ public interface PetApi {
    )
    Mono<ResponseEntity<ModelApiResponse>> uploadFileWithRequiredFile(
         @PathVariable("petId") Long petId,
-         @RequestPart(value = "requiredFile", required = true) Flux<Part> requiredFile,
+         @RequestPart(value = "requiredFile", required = true) Part requiredFile,
         @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata
    );

--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/FakeApi.java
@@ -396,7 +396,7 @@ public interface FakeApi {
        @ApiParam(value = "None") @Valid @RequestPart(value = "int64", required = false) Long int64,
        @ApiParam(value = "None") @Valid @RequestPart(value = "float", required = false) Float _float,
        @ApiParam(value = "None") @Valid @RequestPart(value = "string", required = false) String string,
-        @ApiParam(value = "None") @RequestPart(value = "binary", required = false) Flux<Part> binary,
+        @ApiParam(value = "None") @RequestPart(value = "binary", required = false) Part binary,
        @ApiParam(value = "None") @Valid @RequestPart(value = "date", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date,
        @ApiParam(value = "None") @Valid @RequestPart(value = "dateTime", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) OffsetDateTime dateTime,
        @ApiParam(value = "None") @Valid @RequestPart(value = "password", required = false) String password,
@@ -698,7 +698,7 @@ public interface FakeApi {
    
    default Mono<ModelApiResponse> uploadFileWithRequiredFile(
        @ApiParam(value = "ID of pet to update", required = true) @PathVariable("petId") Long petId,
-        @ApiParam(value = "file to upload", required = true) @RequestPart(value = "requiredFile", required = true) Flux<Part> requiredFile,
+        @ApiParam(value = "file to upload", required = true) @RequestPart(value = "requiredFile", required = true) Part requiredFile,
        @ApiParam(value = "Additional data to pass to server") @Valid @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata,
        @ApiIgnore final ServerWebExchange exchange
    ) {
--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/FakeApiDelegate.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/FakeApiDelegate.java
@@ -238,7 +238,7 @@ public interface FakeApiDelegate {
        Long int64,
        Float _float,
        String string,
-        Flux<Part> binary,
+        Part binary,
        LocalDate date,
        OffsetDateTime dateTime,
        String password,
@@ -411,7 +411,7 @@ public interface FakeApiDelegate {
     * @see FakeApi#uploadFileWithRequiredFile
     */
    default Mono<ModelApiResponse> uploadFileWithRequiredFile(Long petId,
-        Flux<Part> requiredFile,
+        Part requiredFile,
        String additionalMetadata,
        ServerWebExchange exchange) {
        Mono<Void> result = Mono.empty();
--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/PetApi.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/PetApi.java
@@ -365,7 +365,7 @@ public interface PetApi {
    default Mono<ModelApiResponse> uploadFile(
        @ApiParam(value = "ID of pet to update", required = true) @PathVariable("petId") Long petId,
        @ApiParam(value = "Additional data to pass to server") @Valid @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata,
-        @ApiParam(value = "file to upload") @RequestPart(value = "file", required = false) Flux<Part> file,
+        @ApiParam(value = "file to upload") @RequestPart(value = "file", required = false) Part file,
        @ApiIgnore final ServerWebExchange exchange
    ) {
        return getDelegate().uploadFile(petId, additionalMetadata, file, exchange);
--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/PetApiDelegate.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/api/PetApiDelegate.java
@@ -209,7 +209,7 @@ public interface PetApiDelegate {
     */
    default Mono<ModelApiResponse> uploadFile(Long petId,
        String additionalMetadata,
-        Flux<Part> file,
+        Part file,
        ServerWebExchange exchange) {
        Mono<Void> result = Mono.empty();
        exchange.getResponse().setStatusCode(HttpStatus.NOT_IMPLEMENTED);
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApi.java
@@ -386,7 +386,7 @@ public interface FakeApi {
        @ApiParam(value = "None") @Valid @RequestPart(value = "int64", required = false) Long int64,
        @ApiParam(value = "None") @Valid @RequestPart(value = "float", required = false) Float _float,
        @ApiParam(value = "None") @Valid @RequestPart(value = "string", required = false) String string,
-        @ApiParam(value = "None") @RequestPart(value = "binary", required = false) Flux<Part> binary,
+        @ApiParam(value = "None") @RequestPart(value = "binary", required = false) Part binary,
        @ApiParam(value = "None") @Valid @RequestPart(value = "date", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date,
        @ApiParam(value = "None") @Valid @RequestPart(value = "dateTime", required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) OffsetDateTime dateTime,
        @ApiParam(value = "None") @Valid @RequestPart(value = "password", required = false) String password,
@@ -680,7 +680,7 @@ public interface FakeApi {
    
    default Mono<ResponseEntity<ModelApiResponse>> uploadFileWithRequiredFile(
        @ApiParam(value = "ID of pet to update", required = true) @PathVariable("petId") Long petId,
-        @ApiParam(value = "file to upload", required = true) @RequestPart(value = "requiredFile", required = true) Flux<Part> requiredFile,
+        @ApiParam(value = "file to upload", required = true) @RequestPart(value = "requiredFile", required = true) Part requiredFile,
        @ApiParam(value = "Additional data to pass to server") @Valid @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata,
        @ApiIgnore final ServerWebExchange exchange
    ) {
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApiDelegate.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApiDelegate.java
@@ -239,7 +239,7 @@ public interface FakeApiDelegate {
        Long int64,
        Float _float,
        String string,
-        Flux<Part> binary,
+        Part binary,
        LocalDate date,
        OffsetDateTime dateTime,
        String password,
@@ -412,7 +412,7 @@ public interface FakeApiDelegate {
     * @see FakeApi#uploadFileWithRequiredFile
     */
    default Mono<ResponseEntity<ModelApiResponse>> uploadFileWithRequiredFile(Long petId,
-        Flux<Part> requiredFile,
+        Part requiredFile,
        String additionalMetadata,
        ServerWebExchange exchange) {
        Mono<Void> result = Mono.empty();
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/PetApi.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/PetApi.java
@@ -357,7 +357,7 @@ public interface PetApi {
    default Mono<ResponseEntity<ModelApiResponse>> uploadFile(
        @ApiParam(value = "ID of pet to update", required = true) @PathVariable("petId") Long petId,
        @ApiParam(value = "Additional data to pass to server") @Valid @RequestPart(value = "additionalMetadata", required = false) String additionalMetadata,
-        @ApiParam(value = "file to upload") @RequestPart(value = "file", required = false) Flux<Part> file,
+        @ApiParam(value = "file to upload") @RequestPart(value = "file", required = false) Part file,
        @ApiIgnore final ServerWebExchange exchange
    ) {
        return getDelegate().uploadFile(petId, additionalMetadata, file, exchange);
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/PetApiDelegate.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/PetApiDelegate.java
@@ -210,7 +210,7 @@ public interface PetApiDelegate {
     */
    default Mono<ResponseEntity<ModelApiResponse>> uploadFile(Long petId,
        String additionalMetadata,
-        Flux<Part> file,
+        Part file,
        ServerWebExchange exchange) {
        Mono<Void> result = Mono.empty();
        exchange.getResponse().setStatusCode(HttpStatus.NOT_IMPLEMENTED);