Documenting API rate limiting and throttling mechanisms with Java Spring REST Docs

24 Sep 2023

JavaSpringRESTDocs

In today’s digital world, it’s crucial to implement rate limiting and throttling mechanisms in your APIs to ensure optimal performance and prevent abuse. Java Spring REST Docs provides a powerful way to document these mechanisms, making it easier for developers and consumers to understand and work with your APIs. In this blog post, we will explore how to document rate limiting and throttling mechanisms using Java Spring REST Docs.

What is Rate Limiting and Throttling?

Rate limiting is a technique used to control the number of requests a user or client can make within a specific timeframe. It helps to prevent abuse, protect server resources, and maintain a good user experience. Throttling, on the other hand, limits the number of requests processed per unit of time to ensure overall system stability.

Implementation with Java Spring REST Docs

To implement rate limiting and throttling mechanisms in your Java Spring API, you can use libraries and frameworks such as Guava or Spring Cloud Gateway. Once implemented, you can leverage Java Spring REST Docs to document these mechanisms. Here’s how:

Step 1: Configuring API Rate Limiting and Throttling

First, set up the rate limiting and throttling mechanisms in your API. This can be done by incorporating libraries such as Guava RateLimiter or implementing custom request filters.

// Configuration using Guava RateLimiter
@Configuration
public class RateLimitingConfig {
    @Bean
    public RateLimiter rateLimiter() {
        return RateLimiter.create(10); // 10 requests per second
    }
}

// Custom request filter implementation
@Component
public class ThrottlingFilter implements Filter {
    // Implement throttling logic

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // Implement throttling logic

        chain.doFilter(request, response);
    }
}

Step 2: Documenting Rate Limiting and Throttling

Next, we need to document the rate limiting and throttling mechanisms in our API documentation. Java Spring REST Docs provides a convenient way to add documentation snippets to our tests. Let’s look at an example:

@RunWith(SpringRunner.class)
@SpringBootTest
public class ApiDocumentation {

    @Autowired
    private WebApplicationContext context;

    private MockMvc mockMvc;

    @Before
    public void setUp() {
        this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
            .apply(documentationConfiguration(this.restDocumentation))
            .alwaysDo(document("{method-name}", preprocessRequest(prettyPrint()), preprocessResponse(prettyPrint())))
            .build();
    }

    @Test
    public void shouldDocumentRateLimitingAndThrottling() throws Exception {
        // Perform API request and assert rate limit and throttling behavior
        
        this.mockMvc.perform(get("/api/resource"))
            .andExpect(status().isOk())
            .andExpect(jsonPath("$.message").value("Success"))
            .andDo(document("api-resource",
                preprocessRequest(prettyPrint()),
                preprocessResponse(prettyPrint()),
                snippets(
                    requestParameters(
                        parameterWithName("pageSize").description("The page size"),
                        parameterWithName("pageNumber").description("The page number")
                    ),
                    responseFields(
                        fieldWithPath("message").description("The API response message"),
                        fieldWithPath("data").description("The data returned")
                    ),
                    rateLimitingSnippet(),
                    throttlingSnippet()
                )
            ));
    }
}

@Component
public class DocumentationHelper {

    public static RestDocumentationResultHandler rateLimitingSnippet() {
        return document(RestdocsConstants.RATE_LIMITING_SNIPPET);
    }

    public static RestDocumentationResultHandler throttlingSnippet() {
        return document(RestdocsConstants.THROTTLING_SNIPPET);
    }
}

Step 3: Generating API Documentation

Finally, we need to generate the API documentation using Java Spring REST Docs. This can be done by running the tests and utilizing the provided AsciiDoc or Markdown templates. Here’s an example of generating the AsciiDoc documentation:

./gradlew test asciidoctor

Once generated, the documentation can be published and shared with developers and API consumers.

Conclusion

Documenting API rate limiting and throttling mechanisms plays a crucial role in maintaining a reliable and performant API. With Java Spring REST Docs, you can easily document these mechanisms and provide comprehensive API documentation to developers. By following the steps outlined in this blog post, you can improve the usability and clarity of your APIs, enhancing the developer experience and facilitating API adoption.

#API #JavaSpringRESTDocs