使用打开的 api 代码生成器为 spring-webflux 生成 API 接口时，如何防止 Mono 请求正文生成？

Question

I'm creating a spring boot application using spring-webflux and generating the api's using open api code generator. the generated interfaces wrappes the request body with Mono. How to prevent that wrapping? for example instead of generating

public Mono<ResponseEntity<PostApiDto>> createPost(Mono<PostApiDto> body, ServerWebExchange exchange) {

}

i want the generated interface to look like:

public Mono<ResponseEntity<PostApiDto>> createPost(PostApiDto body) {

}

Here is the api spec file and the pom.xml file:-

openapi.yml

openapi: 3.0.3
info:
  title: "instagram-post-service"
  description: ""
  termsOfService: ""
  version: 1.0.0
externalDocs:
  description: ""
  url: ""
servers:
  - url: http://localhost:8080
    description: Generated server url
tags:
  - name: Post
    description: Operations about posts
    externalDocs:
      description: ""
      url: ""
  - name: Comment
    description: Operations about comments
    externalDocs:
      description: ""
      url: ""
    
paths:
  /posts/me/:
    get:
      tags:
      - Post
      summary: find current user posts
      operationId: getMyPosts
      responses:
        200:
          description: successful operation
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/Post'
  /posts/:                  
    post:
      tags:
        - Post
      summary: Create a new Post
      description: ''
      operationId: createPost
      requestBody:
        description: ''
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Post'
        required: true
      responses:
        '200':
          description: Successful operation
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Post'          


components:
  schemas:
    Post:
      type: object
      properties:
        id:
          type: integer
          format: int32
        title:
          type: string
        serviceAddress:
          type: string      

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.2</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <groupId>com.javaworld.instagram</groupId>
    <artifactId>post-service</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>post-service</name>
    <description>instagram posts micro service</description>

    <properties>
        <java.version>1.8</java.version>
        <swagger-annotations-version>1.6.6</swagger-annotations-version>
        <jackson-databind-nullable>0.2.1</jackson-databind-nullable>
        <org.mapstruct.version>1.3.1.Final</org.mapstruct.version>
    </properties>

    <dependencies>
        
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
                
        <!-- ################### Testing dependencies ################################ -->  
    
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-test</artifactId>
        </dependency>       
        
        <!-- ########################### DB & persistence layer dependencies ################################ -->

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
                
    
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>6.1.2.Final</version>
        </dependency>
    

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb-reactive</artifactId>
        </dependency>
        
        <!-- ################### dependencies needed for open-API code generator ################################ -->
        
        <dependency>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-annotations</artifactId>
            <version>${swagger-annotations-version}</version>
        </dependency>

        <dependency>
            <groupId>org.openapitools</groupId>
            <artifactId>jackson-databind-nullable</artifactId>
            <version>${jackson-databind-nullable}</version>
        </dependency>

        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-boot-starter</artifactId>
            <version>3.0.0</version>
        </dependency>


        <!-- ################################ MapStruct ################################################ -->

        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>${org.mapstruct.version}</version>
        </dependency>

        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>${org.mapstruct.version}</version>
        </dependency>

        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>1.1.0.Final</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>

            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <layers>
                        <enabled>true</enabled>
                        <!-- <configuration>${project.basedir}/src/layers.xml</configuration> -->
                    </layers>
                </configuration>
            </plugin>


            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source> 
                    <target>1.8</target> 
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.mapstruct</groupId>
                            <artifactId>mapstruct-processor</artifactId>
                            <version>${org.mapstruct.version}</version>
                        </path>
                        <!-- other annotation processors -->
                    </annotationProcessorPaths>
                </configuration>
            </plugin>

            <!-- open API plug-in for API code generator -->
            <plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <version>6.0.1</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>
                                ${project.basedir}/src/main/resources/openapi.yml
                            </inputSpec>
                            <generatorName>spring</generatorName>
                            <apiPackage>com.javaworld.instagram.postservice.server.api</apiPackage>
                            <modelPackage>com.javaworld.instagram.postservice.server.dto</modelPackage>
                            <modelNameSuffix>ApiDto</modelNameSuffix>
                            <configOptions>
                                <interfaceOnly>true</interfaceOnly>
                                <skipDefaultInterface>true</skipDefaultInterface>
                                <reactive>true</reactive>
                            </configOptions>

                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

Answer 1

You need to customize your own swagger-codegen template files ( api.mustache and bodyParams.mustache ) and add them to your project.

Your pom.xml config

            <plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <version>6.0.1</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>
                                ${project.basedir}/src/main/resources/openapi.yml
                            </inputSpec>
                            <templateDirectory>src/main/resources/openapi-templates</templateDirectory>
                            <generatorName>spring</generatorName>
                            <apiPackage>com.javaworld.instagram.postservice.server.api</apiPackage>
                            <modelPackage>com.javaworld.instagram.postservice.server.dto</modelPackage>
                            <modelNameSuffix>ApiDto</modelNameSuffix>
                            <configOptions>
                                <interfaceOnly>true</interfaceOnly>
                                <skipDefaultInterface>true</skipDefaultInterface>
                                <reactive>true</reactive>
                            </configOptions>

                        </configuration>
                    </execution>
                </executions>
            </plugin>

templateDirectory - directory with mustache templates api.mustache and bodyParams.mustache

Here you can find modified mustache template files for your case.

Output

default Mono<ResponseEntity<PostApiDto>> createPost(@Parameter(name = "",required = true) @RequestBody @Valid PostApiDto postApiDto, @Parameter(hidden = true) ServerWebExchange exchange) {}