Generating RestClient stubs from Swagger OpenAPI in Spring Boot with Gradle

Question

Opposite of: Generate Spring MVC controller from Swagger/OpenAPI

I need to integrate my Spring Boot project with a remote server exposing Swagger OpenApis. I can successfully download the swagger.json descriptor from the service, but I would like some automated help in generating REST stubs for a number of Java methods. I am using Gradle. I prefer to commit the swagger.json into my project to both be able to build offline (the remote services aren't exposed) and leverage Gradle's input caching.

So far I could leverage Swagger generator for Gradle to do the biggest part of work.

I could try

apply plugin: 'org.hidetake.swagger.generator'

dependencies {
    swaggerCodegen 'io.swagger.codegen.v3:swagger-codegen-cli:3.0.5'  // or Swagger Codegen V3
    swaggerCodegen 'org.openapitools:openapi-generator-cli:3.3.4'     // or OpenAPI Generator
}

swaggerSources {
    remoteservice{
        inputFile = file("${project.rootDir}/gradle/swagger-remoteservice.json")
        code {
            language = 'spring'
        }
    }
}

The output was a fully fledged Gradle Spring Boot project in build/swagger-code-remoteservice also containing a Spring Boot executable.

I had to copy the parts I was interested to:

• DTOs. All of them generated automagically That is the biggest part I mentioned
• The *Api interface

Then I had to implement a Spring service leveraging RestTemplate to perform the Swagger operations. Since there are a number of operations to perform, it will take time.

Additional code I had to write

public class ApiRestImpl implements Api, InitializingBean {


    private RestOperations restTemplate;


    @Override
    public void afterPropertiesSet() throws Exception {
        restTemplate = new RestTemplateBuilder()
             ... //authorization
                .build();
    }


    @Override
    public ResponseEntity<Item> getById(Integer id, Boolean bool) {
        UriComponentsBuilder uriBuilder = UriComponentsBuilder.fromHttpUrl(properties.getUrl() + "/api/v1/Items/{id}")
                .queryParam("bool", bool
        return restTemplate.getForEntity(
                uriBuilder.toUriString(),
                Item.class,
                id
        );
    }

}

What I'd like to do

I would like to be generated a fully (or almost fully) working client, possibly based on RestTemplate. Something I can integrate in my own calling code to perform the REST operation.

I could see that Spring Boot projects use a build/generated directory that gets included into the classpath

In this case, I don't like controllers to be generated and eventually scanned at runtime, so I had to copy the output to the source directory.

Answer 1

You could try to use the OpenAPI gradle plugin. The java client generator has a library option "resttemplate".