Using the REST Client Reactive
This guide explains how to use the REST Client Reactive in order to interact with REST APIs. REST Client Reactive is the REST Client implementation compatible with RESTEasy Reactive.
If your application uses a client and exposes REST endpoints, please use RESTEasy Reactive for the server part.
Prerequisites
To complete this guide, you need:
-
Roughly 15 minutes
-
An IDE
-
JDK 11+ installed with
JAVA_HOME
configured appropriately -
Apache Maven 3.8.6
-
Optionally the Quarkus CLI if you want to use it
-
Optionally Mandrel or GraalVM installed and configured appropriately if you want to build a native executable (or Docker if you use a native container build)
Solution
We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.
Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git
, or download an archive.
The solution is located in the rest-client-reactive-quickstart
directory.
Creating the Maven project
First, we need a new project. Create a new project with the following command:
This command generates the Maven project with a REST endpoint and imports:
-
the
resteasy-reactive-jackson
extension for the REST server support. Useresteasy-reactive
instead if you do not wish to use Jackson; -
the
rest-client-reactive-jackson
extension for the REST client support. Userest-client-reactive
instead if you do not wish to use Jackson
If you already have your Quarkus project configured, you can add the rest-client-reactive-jackson
extension
to your project by running the following command in your project base directory:
quarkus extension add 'rest-client-reactive-jackson'
./mvnw quarkus:add-extension -Dextensions='rest-client-reactive-jackson'
./gradlew addExtension --extensions='rest-client-reactive-jackson'
This will add the following to your build file:
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-rest-client-reactive-jackson</artifactId>
</dependency>
implementation("io.quarkus:quarkus-rest-client-reactive-jackson")
Setting up the model
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 a Extension
POJO.
Create a src/main/java/org/acme/rest/client/Extension.java
file and set the following content:
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;
}
The model above is only a subset of the fields provided by the service, but it suffices for the purposes of this guide.
Create the interface
Using the REST Client Reactive is as simple as creating an interface using the proper JAX-RS 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 javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import java.util.Set;
@Path("/extensions")
@RegisterRestClient
public interface ExtensionsService {
@GET
Set<Extension> getById(@QueryParam("id") String id);
}
The getById
method gives our code the ability to get an extension by id from the Code Quarkus API. The client will handle all the networking and marshalling leaving our code clean of such technical details.
The purpose of the annotations in the code above is the following:
-
@RegisterRestClient
allows Quarkus to know that this interface is meant to be available for CDI injection as a REST Client -
@Path
,@GET
and@QueryParam
are the standard JAX-RS annotations used to define how to access the service
When the If you don’t rely on the JSON default, it is heavily recommended to annotate your endpoints with the |
The |
Query Parameters
The easiest way to specify a query parameter is to annotate a client method parameter with the @QueryParam
or the @RestQuery
.
The @RestQuery
is equivalent of the @QueryParam
, but with optional name. Additionally, it can be also used to pass query parameters
as a Map
, which is convenient if parameters are not known in advance.
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import org.jboss.resteasy.reactive.RestQuery;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MultivaluedMap;
import java.util.Map;
import java.util.Set;
@Path("/extensions")
@RegisterRestClient(configKey = "extensions-api")
public interface ExtensionsService {
@GET
Set<Extension> getById(@QueryParam("id") Integer id);
@GET
Set<Extension> getByName(@RestQuery String name); (1)
@GET
Set<Extension> getByFilter(@RestQuery Map<String, String> filter); (2)
@GET
Set<Extension> getByFilters(@RestQuery MultivaluedMap<String, String> filters); (3)
}
1 | Request query will include parameter with key name |
2 | Each Map entry represents exactly one query parameter |
3 | MultivaluedMap allows you to send array values |
Using @ClientQueryParam
Another way to add query parameters to a request is to use @io.quarkus.rest.client.reactive.ClientQueryParam
on either the REST client interface or a specific method of the interface.
The annotation can specify the query parameter name while the value can either be a constant, a configuration property or it can be determined by invoking a method.
The following example shows the various possible usages:
@ClientQueryParam(name = "my-param", value = "${my.property-value}") (1)
public interface Client {
@GET
String getWithParam();
@GET
@ClientQueryParam(name = "some-other-param", value = "other") (2)
String getWithOtherParam();
@GET
@ClientQueryParam(name = "param-from-method", value = "{with-param}") (3)
String getFromMethod();
default String withParam(String name) {
if ("param-from-method".equals(name)) {
return "test";
}
throw new IllegalArgumentException();
}
}
1 | By placing @ClientQueryParam on the interface, we ensure that my-param will be added to all requests of the client.
Because we used the ${…} syntax, the actual value of the parameter will be obtained using the my.property-value configuration property. |
2 | When getWithOtherParam is called, in addition to the my-param query parameter, some-other-param with the value of other will also be added. |
3 | when getFromMethod is called, in addition to the my-param query parameter, param-from-method with the value of test (because that’s what the withParam method returns when invoked with param-from-method ) will also be added. |
Note that if an interface method contains an argument annotated with |
More information about this annotation can be found on the javadoc of
Path Parameters
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 the example below.
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.QueryParam;
import java.util.Set;
@Path("/extensions")
@RegisterRestClient
public interface ExtensionsService {
@GET
@Path("/stream/{stream}")
Set<Extension> getByStream(@PathParam("stream") String stream, @QueryParam("id") String id);
}
Create the configuration
In order to determine the base URL to which REST calls will be made, the REST Client uses configuration from application.properties
.
The name of the property needs to follow a certain convention which is best displayed in the following code:
# Your configuration properties
quarkus.rest-client."org.acme.rest.client.ExtensionsService".url=https://stage.code.quarkus.io/api # (1)
1 | Having this configuration means that all requests performed using org.acme.rest.client.ExtensionsService will use https://stage.code.quarkus.io/api as the base URL.
Using the configuration above, calling the getById method of ExtensionsService with a value of io.quarkus:quarkus-rest-client-reactive would result in an HTTP GET request being made to https://stage.code.quarkus.io/api/extensions?id=io.quarkus:quarkus-rest-client-reactive . |
Note that org.acme.rest.client.ExtensionsService
must match the fully qualified name of the ExtensionsService
interface we created in the previous section.
To facilitate the configuration, you can use the @RegisterRestClient
configKey
property that allows to use different 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=javax.inject.Singleton
Create the JAX-RS resource
Create the src/main/java/org/acme/rest/client/ExtensionsResource.java
file with the following content:
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.inject.RestClient;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import java.util.Set;
@Path("/extension")
public class ExtensionsResource {
@RestClient (1)
ExtensionsService extensionsService;
@GET
@Path("/id/{id}")
public Set<Extension> id(String id) {
return extensionsService.getById(id);
}
}
There are two interesting parts in this listing:
1 | the client stub is injected with the @RestClient annotation instead of the usual CDI @Inject |
Programmatic client creation with RestClientBuilder
Instead of annotating the client with @RegisterRestClient
, and injecting
a client with @RestClient
, you can also create REST Client programmatically.
You do that with RestClientBuilder
.
With this approach the client interface could look as follows:
package org.acme.rest.client;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import java.util.Set;
@Path("/extensions")
public interface ExtensionsService {
@GET
Set<Extension> getById(@QueryParam("id") String id);
}
And the service as follows:
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.RestClientBuilder;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import java.net.URI;
import java.util.Set;
@Path("/extension")
public class ExtensionsResource {
private final ExtensionsService extensionsService;
public ExtensionsResource() {
extensionsService = RestClientBuilder.newBuilder()
.baseUri(URI.create("https://stage.code.quarkus.io/api"))
.build(ExtensionsService.class);
}
@GET
@Path("/id/{id}")
public Set<Extension> id(String id) {
return extensionsService.getById(id);
}
}
Use Custom HTTP Options
The REST Client Reactive internally uses the Vert.x HTTP Client to make the network connections. The REST Client Reactive extensions allows configuring some settings via properties, for example:
-
quarkus.rest-client.client-prefix.connect-timeout
to configure the connect timeout in milliseconds. -
quarkus.rest-client.client-prefix.max-redirects
to limit the number of redirects.
However, there are many more options within the Vert.x HTTP Client to configure the connections. See all the options in the Vert.x HTTP Client Options API in this link.
To fully customize the Vert.x HTTP Client instance that the REST Client Reactive is internally using, you can provide your custom HTTP Client Options instance via CDI or when programmatically creating your client.
Let’s see an example about how to provide the HTTP Client Options via CDI:
package org.acme.rest.client;
import javax.enterprise.inject.Produces;
import javax.ws.rs.ext.ContextResolver;
import io.vertx.core.http.HttpClientOptions;
import io.quarkus.arc.Unremovable;
@Provider
public class CustomHttpClientOptions implements ContextResolver<HttpClientOptions> {
@Override
public HttpClientOptions getContext(Class<?> aClass) {
HttpClientOptions options = new HttpClientOptions();
// ...
return options;
}
}
Now, all the REST Clients will be using your custom HTTP Client Options.
Another approach is to provide the custom HTTP Client options when creating the client programmatically:
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.RestClientBuilder;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import java.net.URI;
import java.util.Set;
import io.vertx.core.http.HttpClientOptions;
@Path("/extension")
public class ExtensionsResource {
private final ExtensionsService extensionsService;
public ExtensionsResource() {
extensionsService = RestClientBuilder.newBuilder()
.baseUri(URI.create("https://stage.code.quarkus.io/api"))
.register(CustomHttpClientOptions.class) (1)
.build(ExtensionsService.class);
}
// ...
}
public class CustomHttpClientOptions implements ContextResolver<HttpClientOptions> {
@Override
public HttpClientOptions getContext(Class<?> aClass) {
HttpClientOptions options = new HttpClientOptions();
// ...
return options;
}
}
1 | the client will use the registered HTTP Client options over the HTTP Client options provided via CDI if any. |
Update the test
Next, we 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 test to:
package org.acme.rest.client;
import io.quarkus.test.junit.QuarkusTest;
import org.junit.jupiter.api.Test;
import static io.restassured.RestAssured.given;
import static org.hamcrest.CoreMatchers.hasItem;
import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.Matchers.greaterThan;
@QuarkusTest
public class ExtensionsResourceTest {
@Test
public void testExtensionsIdEndpoint() {
given()
.when().get("/extension/id/io.quarkus:quarkus-rest-client-reactive")
.then()
.statusCode(200)
.body("$.size()", is(1),
"[0].id", is("io.quarkus:quarkus-rest-client-reactive"),
"[0].name", is("REST Client Reactive"),
"[0].keywords.size()", greaterThan(1),
"[0].keywords", hasItem("rest-client"));
}
}
The code above uses REST Assured's json-path capabilities.
Async Support
To get the full power of the reactive nature of the client, you can use the non-blocking flavor of REST Client Reactive extension,
which comes with support for CompletionStage
and Uni
.
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 org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import java.util.Set;
import java.util.concurrent.CompletionStage;
@Path("/extensions")
@RegisterRestClient(configKey = "extensions-api")
public interface ExtensionsService {
@GET
Set<Extension> getById(@QueryParam("id") String id);
@GET
CompletionStage<Set<Extension>> getByIdAsync(@QueryParam("id") String id);
}
Open the src/main/java/org/acme/rest/client/ExtensionsResource.java
file and update it with the following content:
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.inject.RestClient;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import java.util.Set;
import java.util.concurrent.CompletionStage;
@Path("/extension")
public class ExtensionsResource {
@RestClient
ExtensionsService extensionsService;
@GET
@Path("/id/{id}")
public Set<Extension> id(String id) {
return extensionsService.getById(id);
}
@GET
@Path("/id-async/{id}")
public CompletionStage<Set<Extension>> idAsync(String id) {
return extensionsService.getByIdAsync(id);
}
}
Please note that since the invocation is now non-blocking, the idAsync
method will be invoked on the event loop,
i.e. will not get offloaded to a worker pool thread and thus reducing hardware resource utilization.
See Resteasy reactive execution model for more details.
To test asynchronous methods, add the test method below in ExtensionsResourceTest
:
@Test
public void testExtensionIdAsyncEndpoint() {
given()
.when().get("/extension/id-async/io.quarkus:quarkus-rest-client-reactive")
.then()
.statusCode(200)
.body("$.size()", is(1),
"[0].id", is("io.quarkus:quarkus-rest-client-reactive"),
"[0].name", is("REST Client Reactive"),
"[0].keywords.size()", greaterThan(1),
"[0].keywords", hasItem("rest-client"));
}
The Uni
version is very similar:
package org.acme.rest.client;
import io.smallrye.mutiny.Uni;
import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import java.util.Set;
@Path("/extensions")
@RegisterRestClient(configKey = "extensions-api")
public interface ExtensionsService {
// ...
@GET
Uni<Set<Extension>> getByIdAsUni(@QueryParam("id") String id);
}
The ExtensionsResource
becomes:
package org.acme.rest.client;
import io.smallrye.mutiny.Uni;
import org.eclipse.microprofile.rest.client.inject.RestClient;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import java.util.Set;
@Path("/extension")
public class ExtensionsResource {
@RestClient
ExtensionsService extensionsService;
// ...
@GET
@Path("/id-uni/{id}")
public Uni<Set<Extension>> idUni(String id) {
return extensionsService.getByIdAsUni(id);
}
}
Mutiny
The previous snippet uses Mutiny reactive types. If you are not familiar with Mutiny, check Mutiny - an intuitive reactive programming library. |
When returning a Uni
, every subscription invokes the remote service.
It means you can re-send the request by re-subscribing on the Uni
, or use a retry
as follows:
@RestClient ExtensionsService extensionsService;
// ...
extensionsService.getByIdAsUni(id)
.onFailure().retry().atMost(10);
If you use a CompletionStage
, you would need to call the service’s method to retry.
This difference comes from the laziness aspect of Mutiny and its subscription protocol.
More details about this can be found in the Mutiny documentation.
Custom headers support
There are a few ways in which you can specify custom headers for your REST calls:
-
by registering a
ClientHeadersFactory
or aReactiveClientHeadersFactory
with the@RegisterClientHeaders
annotation -
by specifying the value of the header with
@ClientHeaderParam
-
by specifying the value of the header by
@HeaderParam
The code below demonstrates how to use each of these techniques:
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.annotation.ClientHeaderParam;
import org.eclipse.microprofile.rest.client.annotation.RegisterClientHeaders;
import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import java.util.Set;
@Path("/extensions")
@RegisterRestClient
@RegisterClientHeaders(RequestUUIDHeaderFactory.class) (1)
@ClientHeaderParam(name = "my-header", value = "constant-header-value") (2)
@ClientHeaderParam(name = "computed-header", value = "{org.acme.rest.client.Util.computeHeader}") (3)
public interface ExtensionsService {
@GET
@ClientHeaderParam(name = "header-from-properties", value = "${header.value}") (4)
Set<Extension> getById(@QueryParam("id") String id, @HeaderParam("jaxrs-style-header") String headerValue); (5)
}
1 | There can be only one ClientHeadersFactory per class. With it, you can not only add custom headers, but you can also transform existing ones. See the RequestUUIDHeaderFactory class below for an example of the factory. |
2 | @ClientHeaderParam can be used on the client interface and on methods. It can specify a constant header value… |
3 | … and a name of a method that should compute the value of the header. It can either be a static method or a default method in this interface |
4 | … as well as a value from your application’s configuration |
5 | … or as a normal JAX-RS @HeaderParam annotated argument |
When using Kotlin, if default methods are going to be leveraged, then the Kotlin compiler needs to be configured to use Java’s default interface capabilities. See this for more details. |
A ClientHeadersFactory
can look as follows:
package org.acme.rest.client;
import org.eclipse.microprofile.rest.client.ext.ClientHeadersFactory;
import javax.enterprise.context.ApplicationScoped;
import javax.ws.rs.core.MultivaluedHashMap;
import javax.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;
}
}
As you see in the example above, you can make your ClientHeadersFactory
implementation a CDI bean by
annotating it with a scope-defining annotation, such as @Singleton
, @ApplicationScoped
, etc.
To specify a value for ${header.value}
, simply put the following in your application.properties
:
header.value=value of the header
Also, there is a reactive flavor of ClientHeadersFactory
that allows doing blocking operations. For example:
package org.acme.rest.client;
import io.smallrye.mutiny.Uni;
import org.eclipse.microprofile.rest.client.ext.ClientHeadersFactory;
import javax.enterprise.context.ApplicationScoped;
import javax.ws.rs.core.MultivaluedHashMap;
import javax.ws.rs.core.MultivaluedMap;
import java.util.UUID;
@ApplicationScoped
public class GetTokenReactiveClientHeadersFactory extends ReactiveClientHeadersFactory {
@Inject
Service service;
@Override
public Uni<MultivaluedMap<String, String>> getHeaders(
MultivaluedMap<String, String> incomingHeaders,
MultivaluedMap<String, String> clientOutgoingHeaders);
return Uni.createFrom().item(() -> {
MultivaluedHashMap<String, String> newHeaders = new MultivaluedHashMap<>();
// perform blocking call
newHeaders.add(HEADER_NAME, service.getToken());
return newHeaders;
});
}
}
Default header factory
The @RegisterClientHeaders
annotation can also be used without any custom factory specified. In that case the DefaultClientHeadersFactoryImpl
factory will be used.
If you make a REST client call from a REST resource, this factory will propagate all the headers listed in org.eclipse.microprofile.rest.client.propagateHeaders
configuration property from the resource request to the client request. Individual header names are comma-separated.
@Path("/extensions")
@RegisterRestClient
@RegisterClientHeaders
public interface ExtensionsService {
@GET
Set<Extension> getById(@QueryParam("id") String id);
@GET
CompletionStage<Set<Extension>> getByIdAsync(@QueryParam("id") String id);
}
org.eclipse.microprofile.rest.client.propagateHeaders=Authorization,Proxy-Authorization
Exception handling
The MicroProfile REST Client specification introduces the org.eclipse.microprofile.rest.client.ext.ResponseExceptionMapper
whose purpose is to convert an HTTP response to an exception.
A simple example of implementing such a ResponseExceptionMapper
for the ExtensionsService
discussed above, could be:
public class MyResponseExceptionMapper implements ResponseExceptionMapper<RuntimeException> {
@Override
public RuntimeException toThrowable(Response response) {
if (response.getStatus() == 500) {
throw new RuntimeException("The remote service responded with HTTP 500");
}
return null;
}
}
ResponseExceptionMapper
also defines the getPriority
method which is used in order to determine the priority with which ResponseExceptionMapper
implementations will be called (implementations with a lower value for getPriority
will be invoked first).
If toThrowable
returns an exception, then that exception will be thrown. If null
is returned, the next implementation of ResponseExceptionMapper
in the chain will be called (if there is any).
The class as written above, would not be automatically be used by any REST Client. To make it available to every REST Client of the application, the class needs to be annotated with @Provider
(as long as quarkus.rest-client-reactive.provider-autodiscovery
is not set to false
).
Alternatively, if the exception handling class should only apply to specific REST Client interfaces, you can either annotate the interfaces with @RegisterProvider(MyResponseExceptionMapper.class)
, or register it using configuration using the providers
property of the proper quarkus.rest-client
configuration group.
Using @ClientExceptionMapper
A simpler way to convert HTTP response codes of 400 or above is to use the @ClientExceptionMapper
annotation.
For the ExtensionsService
REST Client interface defined above, an example use of @ClientExceptionMapper
would be:
@Path("/extensions")
@RegisterRestClient
public interface ExtensionsService {
@GET
Set<Extension> getById(@QueryParam("id") String id);
@GET
CompletionStage<Set<Extension>> getByIdAsync(@QueryParam("id") String id);
@ClientExceptionMapper
static RuntimeException toException(Response response) {
if (response.getStatus() == 500) {
return new RuntimeException("The remote service responded with HTTP 500");
}
return null;
}
}
Naturally this handling is per REST Client. @ClientExceptionMapper
uses the default priority if the priority
attribute is not set and the normal rules of invoking all handlers in turn apply.
Methods annotated with @ClientExceptionMapper can also take a java.lang.reflect.Method parameter which is useful if the exception mapping code needs to know the REST Client method that was invoked and caused the exception mapping code to engage.
|
Multipart Form support
REST Client Reactive support multipart messages.
Sending Multipart messages
REST Client Reactive allows sending data as multipart forms. This way you can for example send files efficiently.
To send data as a multipart form, you can just use the regular @RestForm
(or @FormParam
) annotations:
@POST
@Path("/binary")
String sendMultipart(@RestForm File file, @RestForm String otherField);
Parameters specified as File
, Path
, byte[]
or Buffer
are sent as files and default to the
application/octet-stream
MIME type. Other @RestForm
parameter types default to the text/plain
MIME type. You can override these defaults with the @PartType
annotation.
Naturally, you can also group these parameters into a containing class:
public static class Parameters {
@RestForm
File file;
@RestForm
String otherField;
}
@POST
@Path("/binary")
String sendMultipart(Parameters parameters);
Any @RestForm
parameter of the type File
, Path
, byte[]
or Buffer
, as well as any
annotated with @PartType
automatically imply a @Consumes(MediaType.MULTIPART_FORM_DATA)
on the method if there is no @Consumes
present.
If there are @RestForm parameters that are not multipart-implying, then
@Consumes(MediaType.APPLICATION_FORM_URLENCODED) is implied.
|
There are a few modes in which the form data can be encoded. By default,
Rest Client Reactive uses RFC1738.
You can override it by specifying the mode either on the client level,
by setting io.quarkus.rest.client.multipart-post-encoder-mode
RestBuilder property
to the selected value of HttpPostRequestEncoder.EncoderMode
or
by specifying quarkus.rest-client.multipart-post-encoder-mode
in your
application.properties
. Please note that the latter works only for
clients created with the @RegisterRestClient
annotation.
All the available modes are described in the Netty documentation
You can also send JSON multiparts by specifying the @PartType
annotation:
public static class Person {
public String firstName;
public String lastName;
}
@POST
@Path("/json")
String sendMultipart(@RestForm @PartType(MediaType.APPLICATION_JSON) Person person);
Receiving Multipart Messages
REST Client Reactive also supports receiving multipart messages. As with sending, to parse a multipart response, you need to create a class that describes the response data, e.g.
public class FormDto {
@RestForm (1)
@PartType(MediaType.APPLICATION_OCTET_STREAM)
public File file;
@FormParam("otherField") (2)
@PartType(MediaType.TEXT_PLAIN)
public String textProperty;
}
1 | uses the shorthand @RestForm annotation to make a field as a part of a multipart form |
2 | the standard @FormParam can also be used. It allows to override the name of the multipart part. |
Then, create an interface method that corresponds to the call and make it return the FormDto
:
@GET
@Produces(MediaType.MULTIPART_FORM_DATA)
@Path("/get-file")
FormDto data receiveMultipart();
At the moment, multipart response support is subject to the following limitations:
-
files sent in multipart responses can only be parsed to
File
,Path
andFileDownload
-
each field of the response type has to be annotated with
@PartType
- fields without this annotation are ignored
REST Client Reactive needs to know the classes used as multipart return types upfront. If you have an interface method that produces multipart/form-data
, the return type will be discovered automatically. However, if you intend to use the ClientBuilder
API to parse a response as multipart, you need to annotate your DTO class with @MultipartForm
.
The files you download are not automatically removed and can take up a lot of disk space. Consider removing the files when you are done working with them. |
Proxy support
REST Client Reactive supports sending requests through a proxy. It honors the JVM settings for it but also allows to specify both:
-
global client proxy settings, with
quarkus.rest-client.proxy-address
,quarkus.rest-client.proxy-user
,quarkus.rest-client.proxy-password
,quarkus.rest-client.non-proxy-hosts
-
per-client proxy settings, with
quarkus.rest-client.<my-client>.proxy-address
, etc. These are applied only to clients injected with CDI, that is the ones created with@RegisterRestClient
If proxy-address
is set on the client level, the client uses its specific proxy settings. No proxy settings are propagated from the global configuration or JVM properties.
If proxy-address
is not set for the client but is set on the global level, the client uses the global settings.
Otherwise, the client uses the JVM settings.
An example configuration for setting proxy:
# global proxy configuration is used for all clients
quarkus.rest-client.proxy-address=localhost:8182
quarkus.rest-client.proxy-user=<proxy user name>
quarkus.rest-client.proxy-password=<proxy password>
quarkus.rest-client.non-proxy-hosts=example.com
# per-client configuration overrides the global settings for a specific client
quarkus.rest-client.my-client.proxy-address=localhost:8183
quarkus.rest-client.my-client.proxy-user=<proxy user name>
quarkus.rest-client.my-client.proxy-password=<proxy password>
quarkus.rest-client.my-client.url=...
MicroProfile REST Client specification does not allow setting proxy credentials. In order to specify proxy user and proxy password programmatically, you need to cast your RestClientBuilder to RestClientBuilderImpl .
|
Package and run the application
Run the application with:
quarkus dev
./mvnw quarkus:dev
./gradlew --console=plain quarkusDev
Open your browser to http://localhost:8080/extension/id/io.quarkus:quarkus-rest-client-reactive.
You should see a JSON object containing some basic information about this extension.
As usual, the application can be packaged using:
quarkus build
./mvnw install
./gradlew build
And executed with java -jar target/quarkus-app/quarkus-run.jar
.
You can also generate the native executable with:
quarkus build --native
./mvnw install -Dnative
./gradlew build -Dquarkus.package.type=native
Logging traffic
REST Client Reactive can log the requests it sends and the responses it receives.
To enable logging, add the quarkus.rest-client.logging.scope
property to your application.properties
and set it to:
-
request-response
to log the request and response contents, or -
all
to also enable low level logging of the underlying libraries.
As HTTP messages can have large bodies, we limit the amount of body characters logged. The default limit is 100
, you can change it by specifying quarkus.rest-client.logging.body-limit
.
REST Client Reactive is logging the traffic with level DEBUG and does not alter logger properties. You may need to adjust your logger configuration to use this feature. |
An example logging configuration:
quarkus.rest-client.logging.scope=request-response
quarkus.rest-client.logging.body-limit=50
quarkus.log.category."org.jboss.resteasy.reactive.client.logging".level=DEBUG
Mocking the client for tests
If you use a client injected with the @RestClient
annotation, you can easily mock it for tests.
You can do it with Mockito’s @InjectMock
or with QuarkusMock
.
This section shows how to replace your client with a mock. If you would like to get a more in-depth understanding of how mocking works in Quarkus, see the blog post on Mocking CDI beans.
Mocking does not work when using @NativeImageTest or @QuarkusIntegrationTest .
|
Let’s assume you have the following client:
package io.quarkus.it.rest.client.main;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
@Path("/")
@RegisterRestClient
public interface Client {
@GET
String get();
}
Mocking with InjectMock
The simplest approach to mock a client for tests is to use Mockito and @InjectMock
.
First, add the following dependency to your application:
<dependency>
<groupId>io.quarkus</groupId>
<artifactId>quarkus-junit5-mockito</artifactId>
<scope>test</scope>
</dependency>
testImplementation("io.quarkus:quarkus-junit5-mockito")
Then, in your test you can simply use @InjectMock
to create and inject a mock:
package io.quarkus.it.rest.client.main;
import static org.mockito.Mockito.when;
import org.eclipse.microprofile.rest.client.inject.RestClient;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import io.quarkus.test.junit.QuarkusTest;
import io.quarkus.test.junit.mockito.InjectMock;
@QuarkusTest
public class InjectMockTest {
@InjectMock
@RestClient
Client mock;
@BeforeEach
public void setUp() {
when(mock.get()).thenReturn("MockAnswer");
}
@Test
void doTest() {
// ...
}
}
Mocking with QuarkusMock
If Mockito doesn’t meet your needs, you can create a mock programmatically using QuarkusMock
, e.g.:
package io.quarkus.it.rest.client.main;
import org.eclipse.microprofile.rest.client.inject.RestClient;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import io.quarkus.test.junit.QuarkusMock;
import io.quarkus.test.junit.QuarkusTest;
@QuarkusTest
public class QuarkusMockTest {
@BeforeEach
public void setUp() {
Client customMock = new Client() { (1)
@Override
public String get() {
return "MockAnswer";
}
};
QuarkusMock.installMockForType(customMock, Client.class, RestClient.LITERAL); (2)
}
@Test
void doTest() {
// ...
}
}
1 | here we use a manually created implementation of the client interface to replace the actual Client |
2 | note that RestClient.LITERAL has to be passed as the last argument of the installMockForType method |
Using a Mock HTTP Server for tests
In some cases you may want to mock the remote endpoint - the HTTP server - instead of mocking the client itself. This may be especially useful for native tests, or for programmatically created clients.
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.
Known limitations
While the REST Client Reactive extension aims to be a drop-in replacement for the REST Client extension, there are some differences and limitations:
-
the default scope of the client for the new extension is
@ApplicationScoped
while thequarkus-rest-client
defaults to@Dependent
To change this behavior, set thequarkus.rest-client-reactive.scope
property to the fully qualified scope name. -
it is not possible to set
HostnameVerifier
orSSLContext
-
a few things that don’t make sense for a non-blocking implementations, such as setting the
ExecutorService
, don’t work