Don't assume that multipart part without filename is always text

extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/multipart/MultipartBinaryWithoutFilenameTest.java

@@ -0,0 +1,67 @@
+package io.quarkus.resteasy.reactive.server.test.multipart;
+
+import static io.restassured.RestAssured.given;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.function.Supplier;
+
+import jakarta.ws.rs.POST;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.core.MediaType;
+
+import org.jboss.resteasy.reactive.PartType;
+import org.jboss.resteasy.reactive.RestForm;
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusUnitTest;
+
+public class MultipartBinaryWithoutFilenameTest {
+
+    @RegisterExtension
+    static QuarkusUnitTest test = new QuarkusUnitTest()
+            .setArchiveProducer(new Supplier<>() {
+                @Override
+                public JavaArchive get() {
+                    return ShrinkWrap.create(JavaArchive.class)
+                            .addClasses(MultipartDataInputTest.Resource.class, MultipartDataInputTest.Item.class,
+                                    MultipartDataInputTest.Result.class);
+                }
+            });
+    private final File IMAGE_FILE = new File("./src/test/resources/image.png");
+
+    @Test
+    public void test() throws IOException {
+        byte[] bytes = given()
+                .contentType("multipart/form-data")
+                .multiPart("bytes", IMAGE_FILE, "application/png")
+                .when()
+                .post("/test")
+                .then()
+                .statusCode(200)
+                .extract().body().asByteArray();
+
+        assertThat(bytes).isEqualTo(Files.readAllBytes(IMAGE_FILE.toPath()));
+    }
+
+    @Path("/test")
+    public static class Resource {
+
+        @POST
+        public byte[] testMultipart(Input input) {
+            return input.bytes;
+        }
+    }
+
+    public static class Input {
+        @RestForm("bytes")
+        @PartType(MediaType.APPLICATION_OCTET_STREAM)
+        public byte[] bytes;
+
+    }
+}

independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/multipart/MultiPartParserDefinition.java

@@ -23,6 +23,7 @@
 import jakarta.ws.rs.WebApplicationException;
 import jakarta.ws.rs.container.CompletionCallback;
 import jakarta.ws.rs.core.HttpHeaders;
+import jakarta.ws.rs.core.MediaType;
 import jakarta.ws.rs.core.Response;
 
 import org.jboss.logging.Logger;
@@ -339,24 +340,35 @@ public void endPart() {
                 contentBytes.reset();
             } else {
 
-                try {
-                    String charset = defaultEncoding;
-                    String contentType = headers.getFirst(HttpHeaders.CONTENT_TYPE);
-                    if (contentType != null) {
-                        String cs = HeaderUtil.extractQuotedValueFromHeader(contentType, "charset");
+                String contentType = headers.getFirst(HttpHeaders.CONTENT_TYPE);
+                if (isText(contentType)) {
+                    try {
+                        String charset = defaultEncoding;
+                        String cs = contentType != null ? HeaderUtil.extractQuotedValueFromHeader(contentType, "charset")
+                                : null;
                         if (cs != null) {
                             charset = cs;
                         }
-                    }
 
-                    data.add(currentName, contentBytes.toString(charset), charset, headers);
-                } catch (UnsupportedEncodingException e) {
-                    throw new RuntimeException(e);
+                        data.add(currentName, contentBytes.toString(charset), charset, headers);
+                    } catch (UnsupportedEncodingException e) {
+                        throw new RuntimeException(e);
+                    }
+                } else {
+                    data.add(currentName, Arrays.copyOf(contentBytes.toByteArray(), contentBytes.size()), null, headers);
                 }
+
                 contentBytes.reset();
             }
         }
 
+        private boolean isText(String contentType) {
+            if (contentType == null || contentType.isEmpty()) { // https://www.rfc-editor.org/rfc/rfc7578.html#section-4.4 says the default content-type if missing is text/plain
+                return true;
+            }
+            return MediaType.TEXT_PLAIN_TYPE.isCompatible(MediaType.valueOf(contentType));
+        }
+
         public List<Path> getCreatedFiles() {
             return createdFiles;
         }

independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/multipart/MultipartSupport.java

@@ -30,6 +30,7 @@
 import org.jboss.resteasy.reactive.server.core.ResteasyReactiveRequestContext;
 import org.jboss.resteasy.reactive.server.core.ServerSerialisers;
 import org.jboss.resteasy.reactive.server.handlers.RequestDeserializeHandler;
+import org.jboss.resteasy.reactive.server.multipart.FileItem;
 import org.jboss.resteasy.reactive.server.multipart.FormValue;
 import org.jboss.resteasy.reactive.server.multipart.MultipartFormDataInput;
 import org.jboss.resteasy.reactive.server.multipart.MultipartPartReadingException;
@@ -90,7 +91,7 @@ private static Object read(MessageBodyReader<?> reader, String attributeName, Fo
                 @Override
                 public InputStream get() {
                     try {
-                        return Files.newInputStream(value.getFileItem().getFile());
+                        return value.getFileItem().getInputStream();
                     } catch (IOException e) {
                         throw new UncheckedIOException(e);
                     }
@@ -248,7 +249,11 @@ public static byte[] getByteArray(String formName, ResteasyReactiveRequestContex
         }
         if (value.isFileItem()) {
             try {
-                return Files.readAllBytes(value.getFileItem().getFile());
+                FileItem fileItem = value.getFileItem();
+                if (fileItem.isInMemory()) {
+                    return fileItem.getInputStream().readAllBytes();
+                }
+                return Files.readAllBytes(fileItem.getFile());
             } catch (IOException e) {
                 throw new MultipartPartReadingException(e);
             }