refactor!: change Upload to use raw instead of multipart requests (#8242)

Change the Upload component to send files as "raw" requests with the file contents as body, instead of using multipart requests.

Author: Artur-

.gitignore

@@ -36,3 +36,4 @@ error-screenshots
 **/frontend/*.tsx
 dev-bundle
 prod.bundle
+.vaadin-node-tasks.lock

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/src/main/java/com/vaadin/flow/component/upload/tests/UploadView.java

@@ -51,6 +51,7 @@ private void createSimpleUpload() {
         upload.addSucceededListener(event -> {
             try {
                 output.add(event.getFileName());
+                output.add(event.getMIMEType());
                 output.add(IOUtils.toString(
                         buffer.getInputStream(event.getFileName()), "UTF-8"));
             } catch (IOException e) {

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/src/main/java/com/vaadin/flow/component/upload/tests/UploadWithHandlerView.java

@@ -38,9 +38,12 @@ public UploadWithHandlerView() {
         Div handlerEventsOutput = new Div();
 
         InMemoryUploadHandler handler = UploadHandler
-                .inMemory((metaData, bytes) -> UI.getCurrent().access(
-                        () -> output.setText(String.valueOf(bytes.length))))
-                .whenStart(() -> handlerEventsOutput.add("started"))
+                .inMemory((metaData, bytes) -> UI.getCurrent().access(() -> {
+                    String metaInfo = "%s-%s-%s".formatted(metaData.fileName(),
+                            metaData.contentType(),
+                            String.valueOf(bytes.length));
+                    output.setText(metaInfo);
+                })).whenStart(() -> handlerEventsOutput.add("started"))
                 .onProgress((transferred, total) -> handlerEventsOutput
                         .add("-progress"))
                 .whenComplete(success -> {

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/src/test/java/com/vaadin/flow/component/upload/tests/AbstractUploadIT.java

@@ -33,7 +33,22 @@ public abstract class AbstractUploadIT extends AbstractComponentIT {
      * @throws IOException
      */
     File createTempFile(String extension) throws IOException {
-        File tempFile = File.createTempFile("TestFileUpload", "." + extension);
+        return createTempFile("TestFileUpload", extension);
+    }
+
+    /**
+     * Creates a temp file with the provided name and extension for testing
+     * purposes.
+     * 
+     * @param fileName
+     *            the temp file name prefix
+     * @param extension
+     *            the temp file extension without leading dot
+     * @return The generated temp file handle
+     * @throws IOException
+     */
+    File createTempFile(String fileName, String extension) throws IOException {
+        File tempFile = File.createTempFile(fileName, "." + extension);
         BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile));
         writer.write(getTempFileContents());
         writer.close();

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/src/test/java/com/vaadin/flow/component/upload/tests/UploadIT.java

@@ -51,13 +51,16 @@ public void init() {
 
     @Test
     public void testUploadAnyFile() throws Exception {
-        File tempFile = createTempFile("txt");
+        File tempFile = createTempFile("some file", "txt");
         getUpload().upload(tempFile);
 
         String content = uploadOutput.getText();
 
+        String expectedContents = tempFile.getName() + "text/plain"
+                + getTempFileContents();
+
         Assert.assertTrue("Upload content does not contain file details",
-                content.contains(tempFile.getName() + getTempFileContents()));
+                content.contains(expectedContents));
         Assert.assertTrue("Progress update event was not fired properly",
                 content.contains("PROGRESS:" + tempFile.getName()));
     }

vaadin-upload-flow-parent/vaadin-upload-flow-integration-tests/src/test/java/com/vaadin/flow/component/upload/tests/UploadWithHandlerIT.java

@@ -50,7 +50,27 @@ public void init() {
     }
 
     @Test
-    public void uploadWithHandler_uploadSingleFile_fileUploadedAndNoErrorThrown()
+    public void uploadWithHandler_uploadTextFile_fileUploadedAndNoErrorThrown()
+            throws Exception {
+        File tempFile = createTempFile("some file", "txt");
+        upload.upload(tempFile);
+
+        checkLogsForErrors();
+
+        Assert.assertEquals(
+                "Unexpected handler events for upload with using upload handler",
+                "started-completed", eventsOutput.getText());
+
+        String expectedMetadata = "%s-%s-%s".formatted(tempFile.getName(),
+                "text/plain", getTempFileContents().getBytes().length);
+
+        Assert.assertEquals(
+                "Unexpected file metadata for upload with upload handler",
+                expectedMetadata, uploadOutput.getText());
+    }
+
+    @Test
+    public void uploadWithHandler_withLargeBinaryFile_fileUploadedAndNoErrorThrown()
             throws Exception {
         File tempFile = createTempBinaryFile();
         upload.upload(tempFile);
@@ -61,9 +81,12 @@ public void uploadWithHandler_uploadSingleFile_fileUploadedAndNoErrorThrown()
                 "Unexpected handler events for upload with using upload handler",
                 "started-progress-completed", eventsOutput.getText());
 
+        String expectedMetadata = "%s-%s-%s".formatted(tempFile.getName(),
+                "application/octet-stream", FILE_SIZE);
+
         Assert.assertEquals(
-                "Unexpected file size for upload with upload handler",
-                uploadOutput.getText(), String.valueOf(FILE_SIZE));
+                "Unexpected file metadata for upload with upload handler",
+                uploadOutput.getText(), expectedMetadata);
     }
 
     private File createTempBinaryFile() throws IOException {

vaadin-upload-flow-parent/vaadin-upload-flow/src/main/java/com/vaadin/flow/component/upload/Upload.java

@@ -170,8 +170,6 @@ public Upload() {
 
         defaultDropLabelIcon = new UploadIcon();
         setDropLabelIcon(defaultDropLabelIcon);
-
-        getElement().setProperty("uploadFormat", "multipart");
     }
 
     /**