What is Java Spring REST Docs?

Java Spring REST Docs is an open-source library that integrates with Spring MVC and Spring WebFlux to automatically generate documentation for your RESTful APIs. It leverages the popular Asciidoctor markup language to write documentation that is easy to read and understand.

Getting Started

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

dependencies {
    // Other dependencies
    implementation 'org.springframework.restdocs:spring-restdocs'
    testImplementation 'org.springframework.restdocs:spring-restdocs-mockmvc'
}

Or in Maven:

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

Writing Documentation

Once you have added the dependencies, you can start writing documentation for your APIs. Java Spring REST Docs provides a comprehensive set of features to document various aspects of your APIs, such as request and response payloads, status codes, request parameters, headers, etc.

To document an API endpoint, you can create a test class and use the RestDocumentation class provided by Spring REST Docs. Here’s an example:

class UserAPIDocs {

    @Autowired
    private MockMvc mockMvc;

    @BeforeEach
    void setUp(RestDocumentationContextProvider documentationContextProvider) {
        this.mockMvc = MockMvcBuilders
            .webAppContextSetup(context)
            .apply(documentationConfiguration(documentationContextProvider))
            .build();
    }

    @Test
    void getUserById() throws Exception {
        mockMvc.perform(get("/api/users/{id}", 1))
                .andExpect(status().isOk())
                .andDo(document("user/get-by-id",
                        pathParameters(
                            parameterWithName("id").description("The ID of the user")
                        ),
                        responseFields(
                            fieldWithPath("id").description("The ID of the user"),
                            fieldWithPath("name").description("The name of the user")
                        )
                ));
    }

}

In the above example, we are documenting the getUserById endpoint. The document method provides a fluent API to describe the different aspects of the endpoint, such as path parameters and response fields.

Generating Documentation

Once you have written the documentation, you can generate the actual documentation in various formats, such as HTML, PDF, or JSON. Java Spring REST Docs integrates seamlessly with popular documentation generators like Asciidoctor and Swagger.

To generate the documentation, you can use Gradle or Maven tasks. For example, with Gradle, you can run the following command:

./gradlew asciidoctor

This will generate HTML documentation based on your Asciidoctor templates.

Conclusion

Java Spring REST Docs is a fantastic tool for documenting RESTful APIs in Java Spring applications. It simplifies the process of writing and generating API documentation, which is crucial for building scalable and maintainable applications. With its extensive features and easy integration, it is a worthwhile addition to any Java Spring project.

#java #spring #rest #docs