Add support for downloading list of files in REST Client

Closes: quarkusio#41978
(cherry picked from commit e2452d1)

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

@@ -13,6 +13,7 @@
 import static org.jboss.resteasy.reactive.common.processor.ResteasyReactiveDotNames.CONSUMES;
 import static org.jboss.resteasy.reactive.common.processor.ResteasyReactiveDotNames.ENCODED;
 import static org.jboss.resteasy.reactive.common.processor.ResteasyReactiveDotNames.FORM_PARAM;
+import static org.jboss.resteasy.reactive.common.processor.ResteasyReactiveDotNames.LIST;
 import static org.jboss.resteasy.reactive.common.processor.ResteasyReactiveDotNames.MAP;
 import static org.jboss.resteasy.reactive.common.processor.ResteasyReactiveDotNames.MULTI;
 import static org.jboss.resteasy.reactive.common.processor.ResteasyReactiveDotNames.OBJECT;
@@ -221,6 +222,9 @@ public class JaxrsClientReactiveProcessor {
     public static final DotName BYTE = DotName.createSimple(Byte.class.getName());
     public static final MethodDescriptor MULTIPART_RESPONSE_DATA_ADD_FILLER = MethodDescriptor
             .ofMethod(MultipartResponseDataBase.class, "addFiller", void.class, FieldFiller.class);
+    private static final MethodDescriptor ARRAY_LIST_CONSTRUCTOR = MethodDescriptor.ofConstructor(ArrayList.class);
+    private static final MethodDescriptor COLLECTION_ADD = MethodDescriptor.ofMethod(Collection.class, "add", boolean.class,
+            Object.class);
 
     private static final String MULTIPART_FORM_DATA = "multipart/form-data";
 
@@ -569,6 +573,9 @@ private String createFieldFillerForSetter(AnnotationInstance partType, MethodInf
     }
 
     private ResultHandle performValueConversion(Type parameter, MethodCreator set, ResultHandle value) {
+        if (treatMultipartDownloadFieldAsCollection(parameter)) {
+            parameter = parameter.asParameterizedType().arguments().get(0);
+        }
         if (parameter.kind() == CLASS) {
             if (parameter.asClassType().name().equals(FILE)) {
                 // we should get a FileDownload type, let's convert it to File
@@ -586,23 +593,40 @@ private ResultHandle performValueConversion(Type parameter, MethodCreator set, R
     private String createFieldFillerForField(AnnotationInstance partType, FieldInfo field, String partName,
             BuildProducer<GeneratedClassBuildItem> generatedClasses, String dataClassName) {
         String fillerClassName = dataClassName + "$$" + field.name();
+        Type fieldType = field.type();
         try (ClassCreator c = new ClassCreator(new GeneratedClassGizmoAdaptor(generatedClasses, true),
                 fillerClassName, null, FieldFiller.class.getName())) {
-            createFieldFillerConstructor(partType, field.type(), partName, fillerClassName, c);
+            boolean treatAsCollection = treatMultipartDownloadFieldAsCollection(fieldType);
+
+            createFieldFillerConstructor(partType, fieldType, partName, fillerClassName, c);
 
             MethodCreator set = c
                     .getMethodCreator(
                             MethodDescriptor.ofMethod(fillerClassName, "set", void.class, Object.class, Object.class));
 
+            ResultHandle resultObj = set.getMethodParam(0);
             ResultHandle value = set.getMethodParam(1);
-            value = performValueConversion(field.type(), set, value);
-            set.writeInstanceField(field, set.getMethodParam(0), value);
+            value = performValueConversion(fieldType, set, value);
+            if (treatAsCollection) {
+                ResultHandle collection = set.readInstanceField(field, resultObj);
+                BytecodeCreator firstInvocation = set.ifNull(collection).trueBranch();
+                firstInvocation.writeInstanceField(field, resultObj,
+                        firstInvocation.newInstance(ARRAY_LIST_CONSTRUCTOR));
+                set.invokeInterfaceMethod(COLLECTION_ADD, set.readInstanceField(field, resultObj), value);
+            } else {
+                set.writeInstanceField(field, resultObj, value);
+            }
 
             set.returnValue(null);
         }
         return fillerClassName;
     }
 
+    private boolean treatMultipartDownloadFieldAsCollection(Type type) {
+        return (type.kind() == PARAMETERIZED_TYPE) && (LIST.equals(type.name()) || COLLECTION.equals(
+                type.name()));
+    }
+
     private void createFieldFillerConstructor(AnnotationInstance partType, Type type, String partName,
             String fillerClassName, ClassCreator c) {
         MethodCreator ctor = c.getMethodCreator(MethodDescriptor.ofConstructor(fillerClassName));

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

@@ -12,6 +12,7 @@
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
+import java.util.List;
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
@@ -30,6 +31,7 @@
 import org.jboss.resteasy.reactive.MultipartForm;
 import org.jboss.resteasy.reactive.PartType;
 import org.jboss.resteasy.reactive.RestForm;
+import org.jboss.resteasy.reactive.multipart.FileDownload;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
 import org.junit.jupiter.api.extension.RegisterExtension;
@@ -45,13 +47,17 @@ public class MultipartResponseTest {
     public static final String WOO_HOO_WOO_HOO_HOO = "Woo hoo, woo hoo hoo";
     private static final long ONE_GIGA = 1024l * 1024l * 1024l * 1l;
 
+    private static final File TXT_FILE = new File("./src/test/resources/lorem.txt");
+    private static final File HTML_FILE = new File("./src/test/resources/test.html");
+
     @TestHTTPResource
     URI baseUri;
 
     @RegisterExtension
     static final QuarkusUnitTest TEST = new QuarkusUnitTest()
             .withApplicationRoot(
-                    (jar) -> jar.addClasses(TestJacksonBasicMessageBodyReader.class, TestJacksonBasicMessageBodyWriter.class));
+                    (jar) -> jar.addClasses(TestJacksonBasicMessageBodyReader.class, TestJacksonBasicMessageBodyWriter.class,
+                            PathFileDownload.class));
 
     @Test
     void shouldParseMultipartResponse() {
@@ -116,6 +122,22 @@ void shouldParseMultipartResponseWithLargeFile() {
         assertThat(data.file.length()).isEqualTo(ONE_GIGA);
     }
 
+    @Test
+    void shouldParseMultipartResponseWithListOfFiles() {
+        Client client = createClient();
+        FileList data = client.getFileList();
+        assertThat(data.name).isEqualTo("test");
+        assertThat(data.files).hasSize(2);
+    }
+
+    @Test
+    void shouldParseMultipartResponseWithListOfFileDownloads() {
+        Client client = createClient();
+        FileDownloadList data = client.getFileDownloadList();
+        assertThat(data.name).isEqualTo("test");
+        assertThat(data.files).hasSize(2);
+    }
+
     @Test
     void shouldParseMultipartResponseWithNulls() {
         Client client = createClient();
@@ -195,6 +217,16 @@ public interface Client {
         @Path("/large")
         MultipartData getLargeFile();
 
+        @GET
+        @Produces(MediaType.MULTIPART_FORM_DATA)
+        @Path("/file-list")
+        FileList getFileList();
+
+        @GET
+        @Produces(MediaType.MULTIPART_FORM_DATA)
+        @Path("/file-download-list")
+        FileDownloadList getFileDownloadList();
+
         @GET
         @Produces(MediaType.MULTIPART_FORM_DATA)
         @Path("/empty")
@@ -257,6 +289,26 @@ public MultipartData getLargeFile() throws IOException {
             return new MultipartData("foo", file, null, 1984, null);
         }
 
+        @GET
+        @Produces(MediaType.MULTIPART_FORM_DATA)
+        @Path("/file-list")
+        public FileList fileList() {
+            var response = new FileList();
+            response.name = "test";
+            response.files = List.of(TXT_FILE, HTML_FILE);
+            return response;
+        }
+
+        @GET
+        @Produces(MediaType.MULTIPART_FORM_DATA)
+        @Path("/file-download-list")
+        public FileDownloadList fileDownloadList() {
+            var response = new FileDownloadList();
+            response.name = "test";
+            response.files = List.of(new PathFileDownload(TXT_FILE), new PathFileDownload(HTML_FILE));
+            return response;
+        }
+
         @GET
         @Produces(MediaType.MULTIPART_FORM_DATA)
         @Path("/empty")
@@ -394,4 +446,24 @@ public Panda(String weight, String height, String mood) {
             this.mood = mood;
         }
     }
+
+    public static class FileList {
+        @RestForm
+        @PartType(MediaType.TEXT_PLAIN)
+        public String name;
+
+        @RestForm
+        @PartType(MediaType.APPLICATION_OCTET_STREAM)
+        public List<File> files;
+    }
+
+    public static class FileDownloadList {
+        @RestForm
+        @PartType(MediaType.TEXT_PLAIN)
+        public String name;
+
+        @RestForm
+        @PartType(MediaType.APPLICATION_OCTET_STREAM)
+        public List<FileDownload> files;
+    }
 }

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

@@ -0,0 +1,56 @@
+package io.quarkus.rest.client.reactive.multipart;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import org.jboss.resteasy.reactive.multipart.FileDownload;
+
+public class PathFileDownload implements FileDownload {
+    private final String partName;
+    private final File file;
+
+    public PathFileDownload(File file) {
+        this(null, file);
+    }
+
+    public PathFileDownload(String partName, File file) {
+        this.partName = partName;
+        this.file = file;
+    }
+
+    @Override
+    public String name() {
+        return partName;
+    }
+
+    @Override
+    public Path filePath() {
+        return file.toPath();
+    }
+
+    @Override
+    public String fileName() {
+        return file.getName();
+    }
+
+    @Override
+    public long size() {
+        try {
+            return Files.size(file.toPath());
+        } catch (IOException e) {
+            throw new RuntimeException("Failed to get size", e);
+        }
+    }
+
+    @Override
+    public String contentType() {
+        return null;
+    }
+
+    @Override
+    public String charSet() {
+        return null;
+    }
+}

extensions/resteasy-reactive/rest-client/deployment/src/test/resources/lorem.txt

@@ -0,0 +1,5 @@
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut
+enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor
+in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident,
+ sunt in culpa qui officia deserunt mollit anim id est laborum.
+

extensions/resteasy-reactive/rest-client/deployment/src/test/resources/test.html

@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <!-- head definitions go here -->
+</head>
+<body>
+<!-- the content goes here -->
+</body>
+</html>

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

@@ -64,15 +64,23 @@ public static ResponseImpl mapToResponse(RestClientRequestContext context,
                 Object result = multipartData.newInstance();
                 builder.entity(result);
                 List<InterfaceHttpData> parts = context.getResponseMultipartParts();
-                for (FieldFiller fieldFiller : multipartData.getFieldFillers()) {
-                    InterfaceHttpData httpData = getPartForName(parts, fieldFiller.getPartName());
-                    if (httpData == null) {
+                for (InterfaceHttpData httpData : parts) {
+                    FieldFiller fieldFiller = null;
+                    // find the correct filler
+                    for (FieldFiller ff : multipartData.getFieldFillers()) {
+                        if (ff.getPartName().equals(httpData.getName())) {
+                            fieldFiller = ff;
+                            break;
+                        }
+                    }
+                    if (fieldFiller == null) {
                         continue;
-                    } else if (httpData instanceof Attribute) {
+                    }
+                    if (httpData instanceof Attribute at) {
                         // TODO: get rid of ByteArrayInputStream
                         // TODO: maybe we could extract something closer to input stream from attribute
                         ByteArrayInputStream in = new ByteArrayInputStream(
-                                ((Attribute) httpData).getValue().getBytes(StandardCharsets.UTF_8));
+                                at.getValue().getBytes(StandardCharsets.UTF_8));
                         Object fieldValue = context.readEntity(in,
                                 fieldFiller.getFieldType(),
                                 MediaType.valueOf(fieldFiller.getMediaType()),
@@ -83,8 +91,8 @@ public static ResponseImpl mapToResponse(RestClientRequestContext context,
                         if (fieldValue != null) {
                             fieldFiller.set(result, fieldValue);
                         }
-                    } else if (httpData instanceof FileUpload) {
-                        fieldFiller.set(result, new FileDownloadImpl((FileUpload) httpData));
+                    } else if (httpData instanceof FileUpload fu) {
+                        fieldFiller.set(result, new FileDownloadImpl(fu));
                     } else {
                         throw new IllegalArgumentException("Unsupported multipart message element type. " +
                                 "Expected FileAttribute or Attribute, got: " + httpData.getClass());
@@ -122,12 +130,4 @@ public static ResponseImpl mapToResponse(RestClientRequestContext context,
         return builder.build();
     }
 
-    private static InterfaceHttpData getPartForName(List<InterfaceHttpData> parts, String partName) {
-        for (InterfaceHttpData part : parts) {
-            if (partName.equals(part.getName())) {
-                return part;
-            }
-        }
-        return null;
-    }
 }