Support sending Multi<io.vertx.mutiny.core.buffer.Buffer> in REST Client

Closes: #20024

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

@@ -186,6 +186,8 @@
 public class JaxrsClientReactiveProcessor {
 
     private static final String MULTI_BYTE_SIGNATURE = "L" + Multi.class.getName().replace('.', '/') + "<Ljava/lang/Byte;>;";
+    private static final String MULTI_BUFFER_SIGNATURE = "L" + Multi.class.getName().replace('.', '/')
+            + "<Lio/vertx/mutiny/core/buffer/Buffer;>;";
     private static final String FILE_SIGNATURE = "L" + File.class.getName().replace('.', '/') + ";";
     private static final String PATH_SIGNATURE = "L" + java.nio.file.Path.class.getName().replace('.', '/') + ";";
     private static final String BUFFER_SIGNATURE = "L" + Buffer.class.getName().replace('.', '/') + ";";
@@ -985,6 +987,13 @@ A more full example of generated client (with sub-resource) can is at the bottom
                                     getGenericTypeFromArray(methodCreator, methodGenericParametersField, paramIdx),
                                     getAnnotationsFromArray(methodCreator, methodParamAnnotationsField, paramIdx));
                         } else if (param.parameterType == ParameterType.BODY) {
+                            if (param.declaredType.equals(Multi.class.getName())) {
+                                if (!param.signature.equals(MULTI_BUFFER_SIGNATURE)) {
+                                    throw new IllegalArgumentException(
+                                            "When using Multi as body parameter only Multi<io.vertx.mutiny.core.buffer.Buffer> is supported");
+                                }
+                            }
+
                             // just store the index of parameter used to create the body, we'll use it later
                             bodyParameterIdx = paramIdx;
                         } else if (param.parameterType == ParameterType.HEADER) {

extensions/resteasy-reactive/rest-client-reactive/deployment/src/test/java/io/quarkus/rest/client/reactive/SendMultiBufferTest.java

@@ -0,0 +1,60 @@
+package io.quarkus.rest.client.reactive;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.FileNotFoundException;
+import java.net.URI;
+
+import jakarta.ws.rs.POST;
+import jakarta.ws.rs.Path;
+
+import org.eclipse.microprofile.rest.client.RestClientBuilder;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusUnitTest;
+import io.quarkus.test.common.http.TestHTTPResource;
+import io.smallrye.mutiny.Multi;
+import io.vertx.mutiny.core.buffer.Buffer;
+
+public class SendMultiBufferTest {
+
+    @RegisterExtension
+    static final QuarkusUnitTest TEST = new QuarkusUnitTest();
+
+    @TestHTTPResource
+    URI uri;
+
+    @Test
+    public void test() throws FileNotFoundException {
+        Multi<io.vertx.mutiny.core.buffer.Buffer> multi = Multi.createFrom().emitter(e -> {
+            for (int i = 0; i < 1000; i++) {
+                e.emit(Buffer.buffer(String.format("%03d", i)));
+            }
+            e.complete();
+        });
+        Client client = RestClientBuilder.newBuilder().baseUri(uri).build(Client.class);
+
+        long result = client.count(multi);
+
+        assertEquals(3000, result);
+    }
+
+    @Path("test")
+    public interface Client {
+
+        @POST
+        @Path("count")
+        long count(Multi<io.vertx.mutiny.core.buffer.Buffer> multi);
+    }
+
+    @Path("test")
+    public static class Resource {
+
+        @POST
+        @Path("count")
+        public long count(String input) {
+            return input.length();
+        }
+    }
+}

independent-projects/resteasy-reactive/client/runtime/pom.xml

@@ -48,6 +48,10 @@
             <groupId>io.smallrye.common</groupId>
             <artifactId>smallrye-common-vertx-context</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.smallrye.reactive</groupId>
+            <artifactId>smallrye-mutiny-vertx-core</artifactId>
+        </dependency>
 
         <dependency>
             <groupId>org.junit.jupiter</groupId>

independent-projects/resteasy-reactive/client/runtime/src/main/java/org/jboss/resteasy/reactive/client/handlers/ClientSendRequestHandler.java

@@ -46,6 +46,7 @@
 import io.netty.handler.codec.http.multipart.InterfaceHttpData;
 import io.smallrye.mutiny.Multi;
 import io.smallrye.mutiny.Uni;
+import io.smallrye.mutiny.vertx.ReadStreamSubscriber;
 import io.smallrye.stork.api.ServiceInstance;
 import io.vertx.core.AsyncResult;
 import io.vertx.core.Future;
@@ -177,6 +178,20 @@ public void handle(AsyncResult<AsyncFile> openedAsyncFile) {
                                     Vertx.currentContext().owner(), (InputStream) requestContext.getEntity().getEntity(),
                                     httpClientRequest));
                     attachSentHandlers(sent, httpClientRequest, requestContext);
+                } else if (requestContext.isMultiBufferUpload()) {
+                    MultivaluedMap<String, String> headerMap = requestContext.getRequestHeaders()
+                            .asMap();
+                    updateRequestHeadersFromConfig(requestContext, headerMap);
+                    setVertxHeaders(httpClientRequest, headerMap);
+                    Future<HttpClientResponse> sent = httpClientRequest.send(ReadStreamSubscriber.asReadStream(
+                            (Multi<io.vertx.mutiny.core.buffer.Buffer>) requestContext.getEntity().getEntity(),
+                            new Function<>() {
+                                @Override
+                                public Buffer apply(io.vertx.mutiny.core.buffer.Buffer buffer) {
+                                    return buffer.getDelegate();
+                                }
+                            }));
+                    attachSentHandlers(sent, httpClientRequest, requestContext);
                 } else {
                     Future<HttpClientResponse> sent;
                     Buffer actualEntity;

independent-projects/resteasy-reactive/client/runtime/src/main/java/org/jboss/resteasy/reactive/client/impl/RestClientRequestContext.java

@@ -42,6 +42,7 @@
 import org.jboss.resteasy.reactive.spi.ThreadSetupAction;
 
 import io.netty.handler.codec.http.multipart.InterfaceHttpData;
+import io.smallrye.mutiny.Multi;
 import io.smallrye.stork.api.ServiceInstance;
 import io.vertx.core.Context;
 import io.vertx.core.MultiMap;
@@ -498,6 +499,11 @@ public boolean isInputStreamUpload() {
         return entity != null && entity.getEntity() instanceof InputStream;
     }
 
+    public boolean isMultiBufferUpload() {
+        // we don't check the generic because Multi<Buffer> is checked at build time
+        return entity != null && entity.getEntity() instanceof Multi;
+    }
+
     public boolean isMultipart() {
         return entity != null && entity.getEntity() instanceof QuarkusMultipartForm;
     }