Vertx POST HttpClientRequest with body parameter - vert.x

Question

I have to implement a Vertx POST request. Via Postman, the request is done as shown in the following picture:
The tricky part is that the server expects the key "upgrade_file" for the body. I could not find out how to do that with Vertx. This is what I have so far:
Buffer bodyBuffer = Buffer.buffer(body); // body is byte[]
HttpClientRequest request = ...
request.handler( response -> ...
request.end(bodyBuffer);
How can I set "upgrade_file" as the key for the body?

Answer 1

Use a WebClient instead of the HTTP client, it provides dedicated support for submitting forms.
WebClient client = WebClient.create(vertx);
or if you already have created an http client:
WebClient client = WebClient.wrap(httpClient);
Then create the form data as map and send the form using a the right content type
MultiMap form = MultiMap.caseInsensitiveMultiMap();
form.set("upgrade_file", "...");
// Submit the form as a multipart form body
client.post(8080, "yourhost", "/some_address")
.putHeader("content-type", "multipart/form-data")
.sendForm(form, ar -> {
//do something with the response
});
More example see https://vertx.io/docs/vertx-web-client/java/

Answer 2

If you want to send files, the simplest way is using the sendMultipartForm method of Vertx WebClient.
Create a Multipartform firstly.
MultipartForm form = MultipartForm.create()
.attribute("imageDescription", "a very nice image")
.binaryFileUpload(
"imageFile",
"image.jpg",
"/path/to/image",
"image/jpeg");
Then invoke WebClient.sendMultipartForm(form) to send the request.
The generic Vertx HttpClient is a low-level API, you should searialize the form data into a string or buffer, the format is similar to this example file in Vertx GraphQL testing codes. Then send the buffer to the server side.