Only one header value of several is sent with MultipartForm body (#2704)

* [2678] Send multiple headers for url-encoded and multipart-form bodies

Bug: #2678

* Updates after review

We should keep and simplify multipart form headers copying.
The changes in HttpRequestImpl can be reverted.

Signed-off-by: Thomas Segismont <[email protected]>

---------

Signed-off-by: Thomas Segismont <[email protected]>
Co-authored-by: ilia1243 <[email protected]>

Author: tsegismont

vertx-web-client/src/main/java/io/vertx/ext/web/client/impl/HttpContext.java

@@ -443,12 +443,9 @@ private void handleCreateRequest() {
           fail(e);
           return;
         }
-        for (String headerName : this.request.headers().names()) {
-          requestOptions.putHeader(headerName, this.request.headers().get(headerName));
-        }
-        multipartForm.headers().forEach(header -> {
+        for (Map.Entry<String, String> header : multipartForm.headers()) {
           requestOptions.putHeader(header.getKey(), header.getValue());
-        });
+        }
       }
       if (body instanceof ReadStream<?>) {
         ReadStream<Buffer> stream = (ReadStream<Buffer>) body;

vertx-web-client/src/test/java/io/vertx/ext/web/client/tests/WebClientTest.java

@@ -1183,6 +1183,23 @@ public void testFormUrlEncodedUnescaped() throws Exception {
     await();
   }
 
+  @Test
+  public void testFormUrlEncodedMultipleHeaders() throws Exception {
+    server.requestHandler(req -> {
+      req.setExpectMultipart(true);
+      req.endHandler(v -> {
+        assertEquals(Arrays.asList("1", "2"), req.headers().getAll("bla"));
+        req.response().end();
+      });
+    });
+    startServer();
+    MultiMap form = MultiMap.caseInsensitiveMultiMap();
+    HttpRequest<Buffer> builder = webClient.post("/somepath");
+    builder.putHeader("bla", Arrays.asList("1", "2"));
+    builder.sendForm(form).onComplete(onSuccess(resp -> complete()));
+    await();
+  }
+
   @Test
   public void testFormMultipart() throws Exception {
     server.requestHandler(req -> {
@@ -1395,6 +1412,23 @@ static Upload memoryUpload(String name, String filename, Buffer data) {
     }
   }
 
+  @Test
+  public void testMultipartFormMultipleHeaders() throws Exception {
+    server.requestHandler(req -> {
+      req.setExpectMultipart(true);
+      req.endHandler(v -> {
+        assertEquals(Arrays.asList("1", "2"), req.headers().getAll("bla"));
+        req.response().end();
+      });
+    });
+    startServer();
+    HttpRequest<Buffer> builder = webClient.post("somepath");
+    MultipartForm form = MultipartForm.create();
+    builder.putHeader("bla", Arrays.asList("1", "2"));
+    builder.sendMultipartForm(form).onComplete(onSuccess(resp -> complete()));
+    await();
+  }
+
   @Test
   public void testFileUploadWhenFileDoesNotExist() {
     HttpRequest<Buffer> builder = webClient.post("somepath");