Menyiapkan Swagger 2 dengan Spring REST API

Keamanan Top

Saya baru saja mengumumkan kursus Learn Spring Security baru, termasuk materi lengkap yang berfokus pada tumpukan OAuth2 baru di Spring Security 5:

>> LIHAT SISA KURSUS Atas

Saya baru saja mengumumkan kursus Learn Spring baru , yang berfokus pada dasar-dasar Spring 5 dan Spring Boot 2:

>> LIHAT KURSUSnya

1. Ikhtisar

Saat ini, komponen front-end dan back-end sering memisahkan aplikasi web. Biasanya, kami mengekspos API sebagai komponen back-end untuk komponen front-end atau integrasi aplikasi pihak ketiga.

Dalam skenario seperti itu, penting untuk memiliki spesifikasi yang tepat untuk API back-end. Pada saat yang sama, dokumentasi API harus informatif, dapat dibaca, dan mudah diikuti.

Selain itu, dokumentasi referensi harus menjelaskan secara bersamaan setiap perubahan dalam API. Menyelesaikan ini secara manual adalah latihan yang membosankan, jadi otomatisasi proses tidak terhindarkan.

Dalam tutorial ini, kita akan melihat Swagger 2 untuk layanan web Spring REST , menggunakan implementasi Springfox dari spesifikasi Swagger 2.

Jika Anda tidak terbiasa dengan Swagger, kunjungi halaman webnya untuk mempelajari lebih lanjut sebelum melanjutkan tutorial ini.

2. Proyek Sasaran

Pembuatan layanan REST yang akan kami gunakan tidak termasuk dalam cakupan artikel ini. Jika Anda sudah memiliki proyek yang sesuai, gunakanlah. Jika tidak, tautan berikut adalah tempat yang baik untuk memulai:

  • Buat artikel REST API dengan Spring 4 dan Java Config
  • Membangun Layanan Web yang RESTful

3. Menambahkan Dependensi Maven

Seperti disebutkan di atas, kami akan menggunakan implementasi Springfox dari spesifikasi Swagger. Versi terbaru dapat ditemukan di Maven Central.

Untuk menambahkannya ke proyek Maven kami, kami membutuhkan ketergantungan di file pom.xml :

 io.springfox springfox-swagger2 2.9.2 

3.1. Ketergantungan Boot Musim Semi

Untuk proyek berbasis Spring Boot, cukup menambahkan satu dependensi springfox-boot-starter :

 io.springfox springfox-boot-starter 3.0.0 

4. Mengintegrasikan Swagger 2 ke dalam Proyek

4.1. Konfigurasi Java

Konfigurasi Swagger terutama berpusat di sekitar kacang Docket :

@Configuration public class SpringFoxConfig { @Bean public Docket api() { return new Docket(DocumentationType.SWAGGER_2) .select() .apis(RequestHandlerSelectors.any()) .paths(PathSelectors.any()) .build(); } }

Setelah mendefinisikan kacang Docket , metode select () akan mengembalikan instance ApiSelectorBuilder , yang menyediakan cara untuk mengontrol titik akhir yang diekspos oleh Swagger.

Kita dapat mengkonfigurasi predikat untuk memilih RequestHandler dengan bantuan RequestHandlerSelectors dan PathSelectors . Menggunakan any () untuk keduanya akan membuat dokumentasi untuk seluruh API kami tersedia melalui Swagger.

4.2. Konfigurasi Tanpa Spring Boot

Dalam proyek Spring biasa, kita perlu mengaktifkan Swagger 2 secara eksplisit. Untuk melakukannya, kita harus menggunakan @ EnableSwagger2WebMvc di kelas konfigurasi kita :

@Configuration @EnableSwagger2WebMvc public class SpringFoxConfig { }

Selain itu, tanpa Spring Boot, kami tidak memiliki kemewahan konfigurasi otomatis penangan resource kami.

Swagger UI menambahkan sekumpulan resource yang harus kita konfigurasi sebagai bagian dari kelas yang memperluas WebMvcConfigurerAdapter dan dianotasi dengan @EnableWebMvc:

@Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("swagger-ui.html") .addResourceLocations("classpath:/META-INF/resources/"); registry.addResourceHandler("/webjars/**") .addResourceLocations("classpath:/META-INF/resources/webjars/"); }

4.3. Verifikasi

Untuk memverifikasi bahwa Springfox berfungsi, kami dapat mengunjungi URL ini di browser kami:

// localhost: 8080 / spring-security-rest / api / v2 / api-docs

Hasilnya adalah respons JSON dengan sejumlah besar key-value pair, yang sangat tidak bisa dibaca manusia. Untungnya, Swagger menyediakan UI Swagger untuk tujuan ini.

5. Kesombongan UI

Swagger UI adalah solusi bawaan yang membuat interaksi pengguna dengan dokumentasi API yang dibuat oleh Swagger lebih mudah.

5.1. Mengaktifkan UI Swagger Springfox

Untuk menggunakan Swagger UI, kita perlu menambahkan dependensi Maven tambahan:

 io.springfox springfox-swagger-ui 2.9.2 

Sekarang kita bisa mengujinya di browser kita dengan mengunjungi:

// localhost: 8080 / aplikasi-root / swagger-ui /

Dalam kasus kami, omong-omong, URL persisnya adalah:

// localhost: 8080 / spring-security-rest / api / swagger-ui /

Hasilnya akan terlihat seperti ini:

5.2. Menjelajahi Dokumentasi Kesombongan

Within Swagger’s response is a list of all controllers defined in our application. Clicking on any of them will list the valid HTTP methods (DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT).

Expanding each method provides additional useful data, such as response status, content-type, and a list of parameters. It is also possible to try each method using the UI.

Swagger’s ability to be synchronized with our code base is crucial. To demonstrate this, we can add a new controller to our application:

@RestController public class CustomController { @RequestMapping(value = "/custom", method = RequestMethod.POST) public String custom() { return "custom"; } }

Now if we refresh the Swagger documentation, we see custom-controller in the list of controllers. As we know, there is only one method (POST) shown in Swagger’s response.

6. Spring Data REST

Springfox provides support for Spring Data REST through its springfox-data-rest library.

Spring Boot will take care of the auto-configuration if it discovers the spring-boot-starter-data-rest on the classpath.

Now let's create an entity named User:

@Entity public class User { @Id private Long id; private String firstName; private int age; private String email; // getters and setters }

Then we'll create the UserRepository to add CRUD operations on the User entity:

@Repository public interface UserRepository extends CrudRepository { }

Last, we'll import the SpringDataRestConfiguration class to the SpringFoxConfig class:

@EnableSwagger2WebMvc @Import(SpringDataRestConfiguration.class) public class SpringFoxConfig { //... }

Note: We've used the @EnableSwagger2WebMvc annotation to enable Swagger, as it has replaced the @EnableSwagger2 annotation in version 3 of the libraries.

Let's restart the application to generate the specifications for the Spring Data REST APIs:

We can see that Springfox has generated the specifications for the User entity with HTTP methods like GET, POST, PUT, PATCH, and DELETE.

7. Bean Validations

Springfox also supports the bean validation annotations through its springfox-bean-validators library.

First, we'll add the Maven dependency to our pom.xml:

 io.springfox springfox-bean-validators 2.9.2 

Again, if we use Spring Boot, we don't have to provide the above dependency explicitly.

Next, let's add a few validation annotations like @NotNull and @Min to the User entity:

@Entity public class User { //... @NotNull(message = "First Name cannot be null") private String firstName; @Min(value = 15, message = "Age should not be less than 15") @Max(value = 65, message = "Age should not be greater than 65") private int age; }

Finally, we'll import the BeanValidatorPluginsConfiguration class to the SpringFoxConfig class:

@EnableSwagger2 @Import(BeanValidatorPluginsConfiguration.class) public class SpringFoxConfig { //... }

Let's take a look at the changes in the API specifications:

Here, we can observe that the User model has * required on the firstName. Also, the minimum and maximum values are defined for the age.

8. Plugin

In order to add specific features to the API specifications, we can create a Springfox plugin. A plugin can offer various features, from enriching the models and properties to the custom API listings and defaults.

Springfox supports the plugin creation through its spi module. The spi module provides a few interfaces like the ModelBuilderPlugin, ModelPropertyBuilderPlugin, and ApiListingBuilderPlugin that act as an extensibility hook to implement a custom plugin.

To demonstrate the capabilities, let's create a plugin to enrich the email property of the User model. We'll use the ModelPropertyBuilderPlugin interface and set the values of the pattern and example.

First, let's create the EmailAnnotationPlugin class and override the supports method to allow any documentation type, such as Swagger 1.2 and Swagger 2:

@Component @Order(Validators.BEAN_VALIDATOR_PLUGIN_ORDER) public class EmailAnnotationPlugin implements ModelPropertyBuilderPlugin { @Override public boolean supports(DocumentationType delimiter) { return true; } }

Then we'll override the apply method of the ModelPropertyBuilderPlugin to set the values of the builder properties:

@Override public void apply(ModelPropertyContext context) { Optional email = annotationFromBean(context, Email.class); if (email.isPresent()) { context.getSpecificationBuilder().facetBuilder(StringElementFacetBuilder.class) .pattern(email.get().regexp()); context.getSpecificationBuilder().example("[email protected]"); } }

So, the API specifications will show the pattern and example values of the property annotated with the @Email annotation.

Next, we'll add the @Email annotation to the User entity:

@Entity public class User { //... @Email(regexp=".*@.*\\..*", message = "Email should be valid") private String email; }

Last, we'll enable the EmailAnnotationPlugin in the SpringFoxConfig class by registering as a bean:

@Import({BeanValidatorPluginsConfiguration.class}) public class SpringFoxConfig { //... @Bean public EmailAnnotationPlugin emailPlugin() { return new EmailAnnotationPlugin(); } }

Let's check out the EmailAnnotationPlugin in action:

We can see the value of the pattern is the same regex (.*@.*\\..*) from the email property of the User entity.

Similarly, the value of the example ([email protected]) is the same, as defined in the apply method of the EmailAnnotationPlugin.

9. Advanced Configuration

The Docket bean of our application can be configured to give us more control over the API documentation generation process.

9.1. Filtering API for Swagger’s Response

It is not always desirable to expose the documentation for the entire API. We can restrict Swagger’s response by passing parameters to the apis() and paths() methods of the Docket class.

As seen above, RequestHandlerSelectors allows using the any or none predicates but can also be used to filter the API according to the base package, class annotation, and method annotations.

PathSelectors provides additional filtering with predicates, which scan the request paths of our application. We can use any(), none(), regex(), or ant().

In the example below, we will instruct Swagger to include only controllers from a particular package, with specific paths, using the ant() predicate:

@Bean public Docket api() { return new Docket(DocumentationType.SWAGGER_2) .select() .apis(RequestHandlerSelectors.basePackage("com.baeldung.web.controller")) .paths(PathSelectors.ant("/foos/*")) .build(); }

9.2. Custom Information

Swagger also provides some default values in its response, which we can customize, such as “Api Documentation”, “Created by Contact Email”, and “Apache 2.0”.

To change these values, we can use the apiInfo(ApiInfo apiInfo) method — the ApiInfo class that contains custom information about the API:

@Bean public Docket api() { return new Docket(DocumentationType.SWAGGER_2) .select() .apis(RequestHandlerSelectors.basePackage("com.example.controller")) .paths(PathSelectors.ant("/foos/*")) .build() .apiInfo(apiInfo()); } private ApiInfo apiInfo() { return new ApiInfo( "My REST API", "Some custom description of API.", "API TOS", "Terms of service", new Contact("John Doe", "www.example.com", "[email protected]"), "License of API", "API license URL", Collections.emptyList()); }

9.3. Custom Methods Response Messages

Swagger allows globally overriding response messages of HTTP methods through Docket’s globalResponseMessage()method.

First, we need to instruct Swagger not to use default response messages. Suppose we want to override 500 and 403 response messages for all GET methods.

To achieve this, some code must be added to the Docket’s initialization block (original code is excluded for clarity):

.useDefaultResponseMessages(false) .globalResponseMessage(RequestMethod.GET, newArrayList(new ResponseMessageBuilder() .code(500) .message("500 message") .responseModel(new ModelRef("Error")) .build(), new ResponseMessageBuilder() .code(403) .message("Forbidden!") .build()));

10. Swagger UI With an OAuth-Secured API

The Swagger UI provides a number of very useful features that we've covered well so far here. But we can't really use most of these if our API is secured and not accessible.

Let's see how we can allow Swagger to access an OAuth-secured API using the Authorization Code grant type in this example.

We'll configure Swagger to access our secured API using the SecurityScheme and SecurityContext support:

@Bean public Docket api() { return new Docket(DocumentationType.SWAGGER_2).select() .apis(RequestHandlerSelectors.any()) .paths(PathSelectors.any()) .build() .securitySchemes(Arrays.asList(securityScheme())) .securityContexts(Arrays.asList(securityContext())); }

10.1. The Security Configuration

We'll define a SecurityConfiguration bean in our Swagger configuration and set some defaults:

@Bean public SecurityConfiguration security() { return SecurityConfigurationBuilder.builder() .clientId(CLIENT_ID) .clientSecret(CLIENT_SECRET) .scopeSeparator(" ") .useBasicAuthenticationWithAccessCodeGrant(true) .build(); }

10.2. SecurityScheme

Next, we'll define our SecurityScheme; this is used to describe how our API is secured (Basic Authentication, OAuth2, …).

In our case here, we'll define an OAuth scheme used to secure our Resource Server:

private SecurityScheme securityScheme() { GrantType grantType = new AuthorizationCodeGrantBuilder() .tokenEndpoint(new TokenEndpoint(AUTH_SERVER + "/token", "oauthtoken")) .tokenRequestEndpoint( new TokenRequestEndpoint(AUTH_SERVER + "/authorize", CLIENT_ID, CLIENT_SECRET)) .build(); SecurityScheme oauth = new OAuthBuilder().name("spring_oauth") .grantTypes(Arrays.asList(grantType)) .scopes(Arrays.asList(scopes())) .build(); return oauth; }

Note that we used the Authorization Code grant type, for which we need to provide a token endpoint and the authorization URL of our OAuth2 Authorization Server.

And here are the scopes we need to have defined:

private AuthorizationScope[] scopes() { AuthorizationScope[] scopes = { new AuthorizationScope("read", "for read operations"), new AuthorizationScope("write", "for write operations"), new AuthorizationScope("foo", "Access foo API") }; return scopes; }

These sync up with the scopes we actually have defined in our application, for the /foos API.

10.3. SecurityContext

Finally, we need to define a SecurityContext for our example API:

private SecurityContext securityContext() { return SecurityContext.builder() .securityReferences( Arrays.asList(new SecurityReference("spring_oauth", scopes()))) .forPaths(PathSelectors.regex("/foos.*")) .build(); }

Note how the name we used here in the reference — spring_oauth — syncs up with the name we used previously in the SecurityScheme.

10.4. Test

Now that we have everything set up and ready to go, let's take a look at our Swagger UI and try access the Foo API.

We can access the Swagger UI locally:

//localhost:8082/spring-security-oauth-resource/swagger-ui.html

As we can see, a new Authorize button now exists due to our security configurations:

When we click the Authorize button, we can see the following pop-up to authorize our Swagger UI to access the secured API:

Note that:

  • We can already see the CLIENT_ID and CLIENT_SECRET, as we've pre-configured them earlier (but we can still change them).
  • We can now select the scopes we need.

Here's how the secured API is marked:

And now, finally, we can hit our API!

Tentu saja, hampir tidak perlu dikatakan bahwa kita perlu berhati-hati dalam mengekspos UI Swagger secara eksternal, karena sekarang konfigurasi keamanan ini aktif.

11. Kesimpulan

Di artikel ini, kami menyiapkan Swagger 2 untuk menghasilkan dokumentasi untuk Spring REST API. Kami juga mempelajari cara untuk memvisualisasikan dan menyesuaikan keluaran Swagger. Dan terakhir, kami melihat konfigurasi OAuth sederhana untuk Swagger.

The implementasi penuh dari tutorial ini dapat ditemukan dalam proyek GitHub. Untuk melihat penyiapan dalam proyek Boot, lihat modul GitHub ini.

Untuk bagian OAuth, kode tersedia di repositori spring-security-oauth kami.

Dan jika Anda adalah siswa REST With Spring, buka Pelajaran 1 dari Modul 7 untuk mendalami cara menyiapkan Swagger dengan Spring dan Spring Boot.

Keamanan bawah

Saya baru saja mengumumkan kursus Learn Spring Security baru, termasuk materi lengkap yang berfokus pada tumpukan OAuth2 baru di Spring Security 5:

>> LIHAT SISA KURSUS bawah

Saya baru saja mengumumkan kursus Learn Spring baru , yang berfokus pada dasar-dasar Spring 5 dan Spring Boot 2:

>> LIHAT KURSUSnya