spring-restdocs/README.md

Goal

The primary goal of the project is to make it easier to produce accurate documentation of a RESTful service using AsciiDoctor and Spring's MVC Test Framework. The documentation is intended to be an easily read user guide, akin to GitHub's API documentation for example, rather than dense API documentation produced by tools like Swagger.

Quickstart

The project requires Java 7 or later. It's built with Gradle:

$ ./gradlew build install

Once the main project's built, take a look at one of the two sample projects. Both projects implement a RESTful service for creating tagged notes but have different implementations: rest-notes-spring-hateoas is implemented using Spring MVC and Spring Hateoas while rest-notes-spring-data-rest is implemented using Spring Data REST.

To see the sample project's documentation move into its directory and use Gradle to build the documentation. For example:

$ cd rest-notes-spring-data-rest
$ ./gradlew restDocumentation

Once the build is complete, open the generated documentation:

open build/asciidoc/main.html

Every example request and response in the documentation is auto-generated using custom Spring MVC Test result handlers. This ensures that the examples match the service that they are documenting.

How does it work

There are three main pieces involved in using this project to document your RESTful service.

Gradle plugin

A Gradle plugin is provided. This plugin builds on top of the AsciiDoctor plugin and is responsible for producing the documentation during the build. Assuming you've built and installed the project as described in the quick start, the plugin as configured in your project as follows:

buildscript {
	repositories {
		mavenLocal()
		jcenter()
	}
	dependencies {
		classpath 'org.springframework.restdocs:spring-restdocs-gradle-plugin:0.1.0.BUILD-SNAPSHOT'
	}
}

apply plugin: 'org.springframework.restdocs'

Programatically generated snippets

Spring's MVC Test framework is used to make requests to the service that you are documenting. Through the use of a custom JUnit runner and some MockMvc configuration documentation snippets for those request and their responses is automatically generated.

The runner is configured using @RunWith on the documentation class. For example:

@RunWith(RestDocumentationJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = Application.class)
@WebAppConfiguration
public class GettingStartedDocumentation {
	// …
}

RestDocumentationJUnit4ClassRunner is an extension of Spring Framework's SpringJUnit4ClassRunner` so all the standard Spring Test Framework functionality is available.

The MockMvc configuration is applied during its creation. This is typically done in an @Before method, for example:

@Before
public void setUp() {
	this.mockMvc = MockMvcBuilders.webAppContextSetup(this.context)
			.apply(new RestDocumentationConfiguration()).build();
}

With this configuration in place any requests made to the REST service using MockMvc will have their requests and responses documented. For example:

public void getIndex() {
	this.mockMvc.perform(get("/").accept(MediaType.APPLICATION_JSON));
}

The code above will perform a GET request against the index (/) of the service with an accept header indicating that a JSON response is required. It will automatically write the cURL command for the request and the resulting response to files beneath the project's build/generated-documentation directory. This location is automatically configured by the Gradle plugin. The names of the files are determined by the name of the class and method from which the call was made. In this example, the files will be called:

• GettingStartedDocumentation/getIndexRequest.asciidoc
• GettingStartedDocumentation/getIndexResponse.asciidoc

Documentation written in Asciidoc

Producing high-quality, easily readable documentation is difficult and the process is only made harder by trying to write the documentation in an ill-suited format such as Java annotations. This project addresses this by allowing you to write the bulk of your documentation's text as an Asciidoc document. These files should be placed in src/documentation/asciidoc.

To include the programmatically generated snippets in your documentation, you use Asciidoc's include macro. The Gradle plugin provides an attribute, generated, that you can use to reference the directory to which the snippets are written. For example, to include both the request and response snippets described above:

include::{generated}/GettingStartedDocumentation/getIndexRequest.asciidoc[]
include::{generated}/GettingStartedDocumentation/getIndexResponse.asciidoc[]

Learning more

To learn more, take a look at the accompanying sample projects:

• rest-notes-spring-data-rest
• rest-notes-spring-hateoas