Add @ClientFormParam to Reactive REST Client

docs/src/main/asciidoc/rest-client-reactive.adoc

@@ -219,7 +219,82 @@
 priority over anything specified in any `@ClientQueryParam` annotation.
 ====
 
-More information about this annotation can be found on the javadoc of
+More information about this annotation can be found on the javadoc of link:https://javadoc.io/doc/io.quarkus/quarkus-rest-client-reactive/latest/io/quarkus/rest/client/reactive/ClientQueryParam.html[`@ClientQueryParam`].
+
+=== Form Parameters
+
+Form parameters can be specified using `@RestForm` (or `@FormParam`) annotations:
+
+[source, java]
+----
+package org.acme.rest.client;
+
+import org.eclipse.microprofile.rest.client.inject.RegisterRestClient;
+import org.jboss.resteasy.reactive.RestForm;
+
+import jakarta.ws.rs.PORT;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.Consumes;
+import jakarta.ws.rs.FormParam;
+import jakarta.ws.rs.core.MultivaluedMap;
+import java.util.Map;
+import java.util.Set;
+
+@Path("/extensions")
+@RegisterRestClient(configKey = "extensions-api")
+public interface ExtensionsService {
+
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    Set<Extension> postId(@FormParam("id") Integer id);
+
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    Set<Extension> postName(@RestForm String name);
+
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    Set<Extension> postFilter(@RestForm Map<String, String> filter);
+
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    Set<Extension> postFilters(@RestForm MultivaluedMap<String, String> filters);
+
+}
+----
+
+==== Using @ClientFormParam
+
+Form parameters can also be specified using `@ClientFormParam`, similar to `@ClientQueryParam`:
+
+[source, java]
+----
+@ClientFormParam(name = "my-param", value = "${my.property-value}")
+public interface Client {
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    String postWithParam();
+
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    @ClientFormParam(name = "some-other-param", value = "other")
+    String postWithOtherParam();
+
+    @POST
+    @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
+    @ClientFormParam(name = "param-from-method", value = "{with-param}")
+    String postFromMethod();
+
+    default String withParam(String name) {
+        if ("param-from-method".equals(name)) {
+            return "test";
+        }
+        throw new IllegalArgumentException();
+    }
+}
+----
+
+More information about this annotation can be found on the javadoc of link:https://javadoc.io/doc/io.quarkus/quarkus-rest-client-reactive/latest/io/quarkus/rest/client/reactive/ClientFormParam.html[`@ClientFormParam`].
 
 === Path Parameters
 
@@ -520,9 +595,9 @@
 - `quarkus.rest-client.follow-redirects` to enable redirection for all REST clients.
 - `quarkus.rest-client.<client-prefix>.follow-redirects` to enable redirection for a specific REST client.
 
-If this property is true, then REST Client will perform a new request that it receives a redirection response from the HTTP server. 
+If this property is true, then REST Client will perform a new request that it receives a redirection response from the HTTP server.
 
 Additionally, we can limit the number of redirections using the property "max-redirects".
 
 One important note is that according to the https://www.rfc-editor.org/rfc/rfc2616#section-10.3.8[RFC2616] specs, by default the redirection will only happen for GET or HEAD methods. However, in REST Client, you can provide your custom redirect handler to enable redirection on POST or PUT methods, or to follow a more complex logic, via either using the `@ClientRedirectHandler` annotation, CDI or programmatically when creating your client.
 
@@ -994,7 +1069,7 @@
 
 === Injecting the `jakarta.ws.rs.ext.Providers` instance in filters
 
-The `jakarta.ws.rs.ext.Providers` is useful when we need to lookup the provider instances of the current client. 
+The `jakarta.ws.rs.ext.Providers` is useful when we need to lookup the provider instances of the current client.
 
 We can get the `Providers` instance in our filters from the request context as follows:
 
@@ -1086,7 +1161,7 @@
 
 === Using @Blocking annotation in exception mappers
 
-In cases that warrant using `InputStream` as the return type of REST Client method (such as when large amounts of data need to be read): 
+In cases that warrant using `InputStream` as the return type of REST Client method (such as when large amounts of data need to be read):
 
 [source, java]
 ----
@@ -1120,10 +1195,10 @@
 }
 ----
 
-<1> With the `@Blocking` annotation, the MyResponseExceptionMapper exception mapper will be executed in the worker thread pool. 
-<2> Reading the entity is now allowed because we're executing the mapper on the worker thread pool. 
+<1> With the `@Blocking` annotation, the MyResponseExceptionMapper exception mapper will be executed in the worker thread pool.
+<2> Reading the entity is now allowed because we're executing the mapper on the worker thread pool.
 
 Note that you can also use the `@Blocking` annotation when using @ClientExceptionMapper:
 
 [source, java]
 ----
@@ -1288,10 +1363,10 @@
 
 === Receiving compressed messages
 REST Client Reactive also supports receiving compressed messages using GZIP. You can enable the HTTP compression support by adding the property `quarkus.http.enable-compression=true`.
-When this feature is enabled and a server returns a response that includes the header `Content-Encoding: gzip`, REST Client Reactive will automatically decode the content and proceed with the message handling. 
+When this feature is enabled and a server returns a response that includes the header `Content-Encoding: gzip`, REST Client Reactive will automatically decode the content and proceed with the message handling.
 
 == 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`

extensions/resteasy-reactive/jaxrs-client-reactive/deployment/src/main/java/io/quarkus/jaxrs/client/reactive/deployment/JaxrsClientReactiveEnricher.java

@@ -45,6 +45,15 @@ void forSubResourceWebTarget(MethodCreator methodCreator, IndexView index, Class
             MethodInfo rootMethod, MethodInfo subMethod, AssignableResultHandle webTarget,
             BuildProducer<GeneratedClassBuildItem> generatedClasses);
 
+    AssignableResultHandle handleFormParams(MethodCreator methodCreator, IndexView index, ClassInfo interfaceClass,
+            MethodInfo method, BuildProducer<GeneratedClassBuildItem> generatedClasses,
+            AssignableResultHandle formParams, boolean multipart);
+
+    AssignableResultHandle handleFormParamsForSubResource(MethodCreator methodCreator, IndexView index,
+            ClassInfo rootInterfaceClass, ClassInfo subInterfaceClass, MethodInfo rootMethod, MethodInfo subMethod,
+            AssignableResultHandle webTarget, BuildProducer<GeneratedClassBuildItem> generatedClasses,
+            AssignableResultHandle formParams, boolean multipart);
+
     /**
      * Method-level alterations
      *

extensions/resteasy-reactive/jaxrs-client-reactive/deployment/src/main/java/io/quarkus/jaxrs/client/reactive/deployment/JaxrsClientReactiveProcessor.java

@@ -1037,6 +1037,8 @@ A more full example of generated client (with sub-resource) can is at the bottom
                         enricher.getEnricher()
                                 .forWebTarget(methodCreator, index, interfaceClass, jandexMethod, methodTarget,
                                         generatedClasses);
+                        formParams = enricher.getEnricher().handleFormParams(methodCreator, index, interfaceClass, jandexMethod,
+                                generatedClasses, formParams, multipart);
                     }
 
                     AssignableResultHandle builder = methodCreator.createVariable(Invocation.Builder.class);
@@ -1660,6 +1662,9 @@ private void handleSubResourceMethod(List<JaxrsClientReactiveEnricherBuildItem>
                         enricher.getEnricher()
                                 .forSubResourceWebTarget(subMethodCreator, index, interfaceClass, subInterface,
                                         jandexMethod, jandexSubMethod, methodTarget, generatedClasses);
+                        formParams = enricher.getEnricher().handleFormParamsForSubResource(subMethodCreator, index,
+                                interfaceClass, subInterface, jandexMethod, jandexSubMethod, methodTarget, generatedClasses,
+                                formParams, multipart);
                     }
 
                     AssignableResultHandle builder = subMethodCreator.createVariable(Invocation.Builder.class);

extensions/resteasy-reactive/rest-client-reactive/deployment/src/main/java/io/quarkus/rest/client/reactive/deployment/DotNames.java

@@ -14,6 +14,8 @@
 import org.jboss.jandex.DotName;
 
 import io.quarkus.rest.client.reactive.ClientExceptionMapper;
+import io.quarkus.rest.client.reactive.ClientFormParam;
+import io.quarkus.rest.client.reactive.ClientFormParams;
 import io.quarkus.rest.client.reactive.ClientQueryParam;
 import io.quarkus.rest.client.reactive.ClientQueryParams;
 import io.quarkus.rest.client.reactive.ClientRedirectHandler;
@@ -27,6 +29,8 @@ public class DotNames {
 
     public static final DotName CLIENT_QUERY_PARAM = DotName.createSimple(ClientQueryParam.class.getName());
     public static final DotName CLIENT_QUERY_PARAMS = DotName.createSimple(ClientQueryParams.class.getName());
+    public static final DotName CLIENT_FORM_PARAM = DotName.createSimple(ClientFormParam.class.getName());
+    public static final DotName CLIENT_FORM_PARAMS = DotName.createSimple(ClientFormParams.class.getName());
     public static final DotName REGISTER_CLIENT_HEADERS = DotName.createSimple(RegisterClientHeaders.class.getName());
     public static final DotName CLIENT_REQUEST_FILTER = DotName.createSimple(ClientRequestFilter.class.getName());
     public static final DotName CLIENT_RESPONSE_FILTER = DotName.createSimple(ClientResponseFilter.class.getName());