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Using the legacy REST Client

This guide is about the REST Client compatible with RESTEasy Classic which used to be the default Jakarta REST (formerly known as JAX-RS) implementation until Quarkus 2.8.

It is now recommended to use RESTEasy Reactive, which supports equally well traditional blocking workloads and reactive workloads. For more information about RESTEasy Reactive, please see the REST Client Reactive guide and, for the server side, the introductory REST JSON guide or the more detailed RESTEasy Reactive guide.

This guide explains how to use the RESTEasy REST Client in order to interact with REST APIs with very little effort.

there is another guide if you need to write server JSON REST APIs.

Pré-requisitos

Para concluir este guia, você precisa:

  • Cerca de 15 minutos

  • Um IDE

  • JDK 17+ installed with JAVA_HOME configured appropriately

  • Apache Maven 3.9.6

  • Opcionalmente, o Quarkus CLI se você quiser usá-lo

  • Opcionalmente, Mandrel ou GraalVM instalado e configurado apropriadamente se você quiser criar um executável nativo (ou Docker se você usar uma compilação de contêiner nativo)

Solução

Recomendamos que siga as instruções nas seções seguintes e crie a aplicação passo a passo. No entanto, você pode ir diretamente para o exemplo completo.

Clone o repositório Git: git clone https://github.com/quarkusio/quarkus-quickstarts.git, ou baixe um arquivo.

The solution is located in the resteasy-client-quickstart directory.

Criar o projeto Maven

Primeiro, precisamos de um novo projeto. Crie um novo projeto com o seguinte comando:

CLI
quarkus create app org.acme:resteasy-client-quickstart \
    --extension='resteasy,resteasy-jackson,resteasy-client,resteasy-client-jackson' \
    --no-code
cd resteasy-client-quickstart

Para criar um projeto Gradle, adicione a opção --gradle ou --gradle-kotlin-dsl.

Para obter mais informações sobre como instalar e usar a CLI do Quarkus, consulte o guia Quarkus CLI.

Maven
mvn io.quarkus.platform:quarkus-maven-plugin:3.7.1:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=resteasy-client-quickstart \
    -Dextensions='resteasy,resteasy-jackson,resteasy-client,resteasy-client-jackson' \
    -DnoCode
cd resteasy-client-quickstart

Para criar um projeto Gradle, adicione a opção '-DbuildTool=gradle' ou '-DbuildTool=gradle-kotlin-dsl'.

Para usuários do Windows:

  • Se estiver usando cmd, (não use barra invertida '\' e coloque tudo na mesma linha)

  • Se estiver usando o Powershell, envolva os parâmetros '-D' entre aspas duplas, por exemplo, '"-DprojectArtifactId=resteasy-client-quickstart"'

Este comando gera o projeto Maven com um endpoint REST e com importações:

  • the resteasy and resteasy-jackson extensions for the REST server support;

  • the resteasy-client and resteasy-client-jackson extensions for the REST client support.

If you already have your Quarkus project configured, you can add the resteasy-client and the resteasy-client-jackson extensions to your project by running the following command in your project base directory:

CLI
quarkus extension add resteasy-client,resteasy-client-jackson
Maven
./mvnw quarkus:add-extension -Dextensions='resteasy-client,resteasy-client-jackson'
Gradle
./gradlew addExtension --extensions='resteasy-client,resteasy-client-jackson'

Isso adicionará o seguinte ao seu arquivo pom.xml:

pom.xml
<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-resteasy-client</artifactId>
</dependency>
<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-resteasy-client-jackson</artifactId>
</dependency>
build.gradle
implementation("io.quarkus:quarkus-resteasy-client")
implementation("io.quarkus:quarkus-resteasy-client-jackson")

Configurando o modelo

In this guide we will be demonstrating how to consume part of the REST API supplied by the stage.code.quarkus.io service. Our first order of business is to set up the model we will be using, in the form of an Extension POJO.

Crie um arquivo src/main/java/org/acme/rest/client/Extension.java e defina o seguinte conteúdo:

package org.acme.rest.client;

import java.util.List;

public class Extension {

    public String id;
    public String name;
    public String shortName;
    public List<String> keywords;

}

O modelo acima é apenas um subconjunto dos campos fornecidos pelo serviço, mas é suficiente para os objetivos deste guia.

Crie a interface

Using the RESTEasy REST Client is as simple as creating an interface using the proper Jakarta REST and MicroProfile annotations. In our case the interface should be created at src/main/java/org/acme/rest/client/ExtensionsService.java and have the following content:

package org.acme.rest.client;

import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import org.jboss.resteasy.annotations.jaxrs.QueryParam;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.QueryParam;
import java.util.Set;

@Path("/extensions")
@RegisterRestClient
public interface ExtensionsService {

    @GET
    Set<Extension> getById(@QueryParam String id);
}

O método getById dá ao nosso código a capacidade de obter uma extensão por id a partir da API do Code Quarkus. O cliente tratará de toda a ligação em rede e da organização, deixando o nosso código livre desses pormenores técnicos.

O objetivo das anotações no código acima é o seguinte:

  • @RegisterRestClient permite que o Quarkus saiba que essa interface deve estar disponível para injeção de CDI como um Cliente REST

  • @Path, @GET e @QueryParam são as anotações Jakarta REST padrão utilizadas para definir o modo de acesso ao serviço

When a JSON extension is installed such as quarkus-resteasy-client-jackson or quarkus-resteasy-client-jsonb, Quarkus will use the application/json media type by default for most return values, unless the media type is explicitly set via @Produces or @Consumes annotations (there are some exceptions for well known types, such as String and File, which default to text/plain and application/octet-stream respectively).

If you don’t want JSON by default you can set quarkus.resteasy-json.default-json=false and the default will change back to being auto-negotiated. If you set this you will need to add @Produces(MediaType.APPLICATION_JSON) and @Consumes(MediaType.APPLICATION_JSON) to your endpoints in order to use JSON.

Se você não conta com JSON padrão, é altamente recomendável anotar seus endpoints com as anotações @Produces e @Consumes para definir com precisão os tipos de conteúdo esperados. Isso permitirá reduzir o número de provedores Jakarta REST (que podem ser vistos como conversores) incluídos no executável nativo.

Parâmetros do Caminho

If the GET request requires path parameters you can leverage the @PathParam("parameter-name") annotation instead of (or in addition to) the @QueryParam. Path and query parameters can be combined, as required, as illustrated in a mock example below.

package org.acme.rest.client;

import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import org.jboss.resteasy.annotations.jaxrs.PathParam;
import org.jboss.resteasy.annotations.jaxrs.QueryParam;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import java.util.Set;

@Path("/extensions")
@RegisterRestClient
public interface ExtensionsService {

    @GET
    @Path("/stream/{stream}")
    Set<Extension> getByStream(@PathParam String stream, @QueryParam("id") String id);
}

Crie a configuração

Para determinar o URL de base para o qual as chamadas REST serão feitas, o Cliente REST usa a configuração de application.properties. O nome da propriedade precisa seguir uma determinada convenção que é melhor exibida no código a seguir:

# Your configuration properties
quarkus.rest-client."org.acme.rest.client.ExtensionsService".url=https://stage.code.quarkus.io/api # (1)
quarkus.rest-client."org.acme.rest.client.ExtensionsService".scope=jakarta.inject.Singleton # (2)
1 Having this configuration means that all requests performed using ExtensionsService will use https://stage.code.quarkus.io as the base URL. Using the configuration above, calling the getById method of ExtensionsService with a value of io.quarkus:quarkus-resteasy-client would result in an HTTP GET request being made to https://stage.code.quarkus.io/api/extensions?id=io.quarkus:quarkus-rest-client.
2 Having this configuration means that the default scope of ExtensionsService will be @Singleton. Supported scope values are @Singleton, @Dependent, @ApplicationScoped and @RequestScoped. The default scope is @Dependent. The default scope can also be defined on the interface.

Note que org.acme.rest.client.ExtensionsService deve corresponder ao nome totalmente qualificado da interface ExtensionsService que criamos na seção anterior.

The standard MicroProfile Rest Client properties notation can also be used to configure the client:

org.acme.rest.client.ExtensionsService/mp-rest/url=https://stage.code.quarkus.io/api
org.acme.rest.client.ExtensionsService/mp-rest/scope=jakarta.inject.Singleton

If a property is specified via both the Quarkus notation and the MicroProfile notation, the Quarkus notation takes a precedence.

To facilitate the configuration, you can use the @RegisterRestClient configKey property that allows to use another configuration root than the fully qualified name of your interface.

@RegisterRestClient(configKey="extensions-api")
public interface ExtensionsService {
    [...]
}
# Your configuration properties
quarkus.rest-client.extensions-api.url=https://stage.code.quarkus.io/api
quarkus.rest-client.extensions-api.scope=jakarta.inject.Singleton

Desabilitando a Verificação do Nome do Host

Para desabilitar a verificação do nome do host SSL para um cliente REST específico, adicione a seguinte propriedade à sua configuração:

quarkus.rest-client.extensions-api.verify-host=false

Esta definição não deve ser utilizada em produção, uma vez que irá desativar a verificação do nome do host SSL.

Moreover, you can configure a REST client to use your custom hostname verify strategy. All you need to do is to provide a class that implements the interface javax.net.ssl.HostnameVerifier and add the following property to your configuration:

quarkus.rest-client.extensions-api.hostname-verifier=<full qualified custom hostname verifier class name>

Quarkus REST client provides an embedded hostname verifier strategy to disable the hostname verification called io.quarkus.restclient.NoopHostnameVerifier.

Disabling SSL verifications

To disable all SSL verifications, add the following property to your configuration:

quarkus.tls.trust-all=true

This setting should not be used in production as it will disable any kind of SSL verification.

Crie o recurso Jakarta REST

Crie o arquivo src/main/java/org/acme/rest/client/ExtensionsResource.java com o seguinte conteúdo:

package org.acme.rest.client;

import org.eclipse.microprofile.rest.client.inject.RestClient;
import org.jboss.resteasy.annotations.jaxrs.PathParam;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import java.util.Set;

@Path("/extension")
public class ExtensionsResource {

    @Inject
    @RestClient
    ExtensionsService extensionsService;

    @GET
    @Path("/id/{id}")
    public Set<Extension> id(@PathParam String id) {
        return extensionsService.getById(id);
    }
}

Note that in addition to the standard CDI @Inject annotation, we also need to use the MicroProfile @RestClient annotation to inject ExtensionsService.

Atualize o teste

We also need to update the functional test to reflect the changes made to the endpoint. Edit the src/test/java/org/acme/rest/client/ExtensionsResourceTest.java file and change the content of the testExtensionIdEndpoint method to:

package org.acme.rest.client;

import static io.restassured.RestAssured.given;
import static org.hamcrest.CoreMatchers.hasItem;
import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.Matchers.greaterThan;

import org.acme.rest.client.resources.WireMockExtensionsResource;
import org.junit.jupiter.api.Test;

import io.quarkus.test.common.QuarkusTestResource;
import io.quarkus.test.junit.QuarkusTest;

@QuarkusTest
@QuarkusTestResource(WireMockExtensionsResource.class)
public class ExtensionsResourceTest {

    @Test
    public void testExtensionsIdEndpoint() {
        given()
            .when().get("/extension/id/io.quarkus:quarkus-rest-client")
            .then()
            .statusCode(200)
            .body("$.size()", is(1),
                "[0].id", is("io.quarkus:quarkus-rest-client"),
                "[0].name", is("REST Client Classic"),
                "[0].keywords.size()", greaterThan(1),
                "[0].keywords", hasItem("rest-client"));
    }
}

O código acima utiliza as capacidades json-path do REST Assured.

Redirecionamento

A HTTP server can redirect a response to another location by sending a response with a status code that starts with "3" and a HTTP header "Location" holding the URL to be redirected to. When the REST Client receives a redirection response from a HTTP server, it won’t automatically perform another request to the new location. However, you can enable the automatic redirection by enabling the "follow-redirects" property:

  • quarkus.rest-client.follow-redirects para ativar o redirecionamento para todos os clientes REST.

  • quarkus.rest-client.<client-prefix>.follow-redirects para ativar o redirecionamento para um cliente REST específico.

Se esta propriedade for verdadeira, então o Cliente REST efetuará uma nova requisição quando receber uma resposta de redirecionamento do servidor HTTP.

Além disso, podemos limitar o número de redirecionamentos utilizando a propriedade "max-redirects".

One important note is that according to the RFC2616 specs, by default the redirection will only happen for GET or HEAD methods.

Suporte Assíncrono

The rest client supports asynchronous rest calls. Async support comes in 2 flavors: you can return a CompletionStage or a Uni (requires the quarkus-rest-client-mutiny extension). Let’s see it in action by adding a getByIdAsync method in our ExtensionsService REST interface. The code should look like:

package org.acme.rest.client;

import java.util.Set;
import java.util.concurrent.CompletionStage;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import org.jboss.resteasy.annotations.jaxrs.QueryParam;

@Path("/extensions")
@RegisterRestClient
public interface ExtensionsService {

    @GET
    Set<Extension> getById(@QueryParam String id);

    @GET
    CompletionStage<Set<Extension>> getByIdAsync(@QueryParam String id);

}

Abra o arquivo src/main/java/org/acme/rest/client/ExtensionsResource.java e atualize-o com o seguinte conteúdo:

package org.acme.rest.client;

import java.util.Set;
import java.util.concurrent.CompletionStage;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.rest.client.inject.RestClient;
import org.jboss.resteasy.annotations.jaxrs.PathParam;

@Path("/extension")
public class ExtensionsResource {

    @Inject
    @RestClient
    ExtensionsService extensionsService;

    @GET
    @Path("/id/{id}")
    public Set<Extension> id(@PathParam String id) {
        return extensionsService.getById(id);
    }

    @GET
    @Path("/id-async/{id}")
    public CompletionStage<Set<Extension>> idAsync(@PathParam String id) {
        return extensionsService.getByIdAsync(id);
    }

}

Para testar métodos assíncronos, adicione o método de teste abaixo em ExtensionsResourceTest:

@Test
public void testExtensionIdAsyncEndpoint() {
    given()
        .when().get("/extension/id-async/io.quarkus:quarkus-rest-client")
        .then()
        .statusCode(200)
        .body("$.size()", is(1),
            "[0].id", is("io.quarkus:quarkus-rest-client"),
            "[0].name", is("REST Client Classic"),
            "[0].keywords.size()", greaterThan(1),
            "[0].keywords", hasItem("rest-client"));
}

A versão Uni é muito semelhante:

package org.acme.rest.client;

import java.util.Set;
import java.util.concurrent.CompletionStage;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import org.jboss.resteasy.annotations.jaxrs.QueryParam;

import io.smallrye.mutiny.Uni;

@Path("/extensions")
@RegisterRestClient
public interface ExtensionsService {

    // ...

    @GET
    Uni<Set<Extension>> getByIdAsUni(@QueryParam String id);
}

O ExtensionsResource torna-se:

package org.acme.rest.client;

import java.util.Set;
import java.util.concurrent.CompletionStage;

import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.rest.client.inject.RestClient;
import org.jboss.resteasy.annotations.jaxrs.PathParam;

import io.smallrye.mutiny.Uni;

@Path("/extension")
public class ExtensionsResource {

    @Inject
    @RestClient
    ExtensionsService extensionsService;


    // ...

    @GET
    @Path("/id-uni/{id}")
    public Uni<Set<Extension>> idMutiny(@PathParam String id) {
        return extensionsService.getByIdAsUni(id);
    }
}
Mutiny

O código anterior usa tipos reativos do Mutiny. Se você não estiver familiarizado com o Mutiny, consulte Mutiny - uma biblioteca de programação reativa intuitiva .

Ao retornar um Uni , cada assinatura invoca o serviço remoto. Isso significa que você pode reenviar a requisição assinando novamente o Uni , ou usar um retry da seguinte forma:

@Inject @RestClient ExtensionsService extensionsService;

// ...

extensionsService.getByIdAsUni(id)
    .onFailure().retry().atMost(10);

Se você usar um CompletionStage , precisará chamar o método do serviço para tentar novamente. Essa diferença vem do aspecto preguiçoso do Mutiny e de seu protocolo de assinatura. Mais detalhes sobre isso podem ser encontrados na documentação do Mutiny .

Suporte para cabeçalhos personalizados

The MicroProfile REST client allows amending request headers by registering a ClientHeadersFactory with the @RegisterClientHeaders annotation.

Let’s see it in action by adding a @RegisterClientHeaders annotation pointing to a RequestUUIDHeaderFactory class in our ExtensionsService REST interface:

package org.acme.rest.client;

import java.util.Set;
import java.util.concurrent.CompletionStage;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;

import org.eclipse.microprofile.rest.client.annotation.RegisterClientHeaders;
import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import org.jboss.resteasy.annotations.jaxrs.QueryParam;

import io.smallrye.mutiny.Uni;

@Path("/extensions")
@RegisterRestClient
@RegisterClientHeaders(RequestUUIDHeaderFactory.class)
public interface ExtensionsService {

    @GET
    Set<Extension> getById(@QueryParam String id);

    @GET
    CompletionStage<Set<Extension>> getByIdAsync(@QueryParam String id);

    @GET
    Uni<Set<Extension>> getByIdAsUni(@QueryParam String id);
}

And the RequestUUIDHeaderFactory would look like:

package org.acme.rest.client;

import org.eclipse.microprofile.rest.client.ext.ClientHeadersFactory;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.ws.rs.core.MultivaluedHashMap;
import jakarta.ws.rs.core.MultivaluedMap;
import java.util.UUID;

@ApplicationScoped
public class RequestUUIDHeaderFactory implements ClientHeadersFactory {

    @Override
    public MultivaluedMap<String, String> update(MultivaluedMap<String, String> incomingHeaders, MultivaluedMap<String, String> clientOutgoingHeaders) {
        MultivaluedMap<String, String> result = new MultivaluedHashMap<>();
        result.add("X-request-uuid", UUID.randomUUID().toString());
        return result;
    }
}

Como você vê no exemplo acima, é possível tornar a implementação do ClientHeadersFactory um bean CDI anotando-o com uma anotação de definição de escopo, como @Singleton , @ApplicationScoped , etc.

Fábrica de cabeçalhos padrão

You can also use @RegisterClientHeaders annotation without any custom factory specified. In that case the DefaultClientHeadersFactoryImpl factory will be used and all headers listed in org.eclipse.microprofile.rest.client.propagateHeaders configuration property will be amended. Individual header names are comma-separated.

@Path("/extensions")
@RegisterRestClient
@RegisterClientHeaders
public interface ExtensionsService {

    @GET
    Set<Extension> getById(@QueryParam String id);

    @GET
    CompletionStage<Set<Extension>> getByIdAsync(@QueryParam String id);

    @GET
    Uni<Set<Extension>> getByIdAsUni(@QueryParam String id);
}
org.eclipse.microprofile.rest.client.propagateHeaders=Authorization,Proxy-Authorization

Empacote e execute a aplicação

Execute a aplicação com:

CLI
quarkus dev
Maven
./mvnw quarkus:dev
Gradle
./gradlew --console=plain quarkusDev

You should see a JSON object containing some basic information about the REST Client extension.

Como de costume, a aplicação pode ser empacotada utilizando:

CLI
quarkus build
Maven
./mvnw install
Gradle
./gradlew build

E executado com java -jar target/quarkus-app/quarkus-run.jar.

Também é possível gerar o executável nativo com:

CLI
quarkus build --native
Maven
./mvnw install -Dnative
Gradle
./gradlew build -Dquarkus.package.type=native

REST Client and RESTEasy interactions

In Quarkus, the REST Client extension and the RESTEasy extension share the same infrastructure. One important consequence of this consideration is that they share the same list of providers (in the Jakarta REST meaning of the word).

For instance, if you declare a WriterInterceptor, it will by default intercept both the servers calls and the client calls, which might not be the desired behavior.

However, you can change this default behavior and constrain a provider to:

  • only consider client calls by adding the @ConstrainedTo(RuntimeType.CLIENT) annotation to your provider;

  • only consider server calls by adding the @ConstrainedTo(RuntimeType.SERVER) annotation to your provider.

Usando um Servidor HTTP Simulado para testes

Em alguns casos, você pode querer simular o endpoint remoto - o servidor HTTP - em vez de simular o próprio cliente. Isso pode ser especialmente útil para testes nativos ou para clientes criados programaticamente.

You can easily mock an HTTP Server with Wiremock. The Wiremock section of the Quarkus - Using the REST Client describes how to set it up in detail.

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