In this blog post, we will discuss how to document API endpoints and their descriptions using Java Spring REST Docs. Proper documentation of API endpoints is crucial for developers who want to understand how to consume the API and for API consumers who want to integrate it into their applications.

What is Java Spring REST Docs?

Java Spring REST Docs is a library that provides support for documenting RESTful APIs in Spring applications. It allows you to generate documentation that describes the different API endpoints, their request and response formats, and any additional information you want to include.

Getting Started

To get started with Java Spring REST Docs, you need to add the necessary dependencies to your project. Add the following dependencies to your pom.xml or build.gradle file:

// Maven
<dependency>
    <groupId>org.springframework.restdocs</groupId>
    <artifactId>spring-restdocs-mockmvc</artifactId>
    <version>2.0.3.RELEASE</version>
    <scope>test</scope>
</dependency>

// Gradle
testImplementation 'org.springframework.restdocs:spring-restdocs-mockmvc:2.0.3.RELEASE'

Once you have added the dependencies, you can start documenting your API endpoints.

Documenting API Endpoints

To document an API endpoint, you need to create a test method that performs a request to the endpoint and generates the documentation using Spring REST Docs. Here’s an example of how to document a GET request to the /users endpoint:

@Test
public void getUsers() throws Exception {
    mockMvc.perform(get("/users"))
            .andExpect(status().isOk())
            .andDo(document("users/get",
                    responseFields(
                            fieldWithPath("id").description("User ID"),
                            fieldWithPath("name").description("User name"),
                            fieldWithPath("email").description("User email")
                    )
            ));
}

In the example above, we use the mockMvc object to perform a GET request to /users. We then specify the expected response status code using andExpect(status().isOk()). Finally, we use the andDo(document(...)) method to generate the documentation. Inside the document(...) method, we use responseFields(...) to describe the response fields of the endpoint.

The generated documentation will include the endpoint’s request and response formats, along with the descriptions provided.

Generating Documentation

To generate the documentation, you need to run the test methods that perform requests to the API endpoints. After running the tests, the documentation will be generated as HTML or Asciidoctor files.

You can configure the output format by adding the following properties to your application.properties or application.yml file:

# HTML output
spring.restdocs.outputdir=docs/html

# Asciidoctor output
spring.restdocs.outputdir=docs/asciidoc
spring.restdocs.snippets.snippet-encoding=UTF-8

This configuration will generate the documentation in either HTML or Asciidoctor format, depending on your preference. The generated files will be stored in the docs/html or docs/asciidoc directory.

Conclusion

Documenting API endpoints using Java Spring REST Docs is essential for clarity and understanding. By following the steps outlined in this blog post, you can easily generate comprehensive API documentation that will help both developers and API consumers.

Remember to provide clear descriptions for your API endpoints and their request and response formats. This will ensure that anyone who interacts with your API has the necessary information to use it effectively.

#hashtags: #Java #Spring #RESTDocs