Strange issue with Vertx Http request - httpclient

Question

I configured an HTTPS website on AWS, which allows visiting from a white list of IPs.
My local machine runs with a VPN connection, which is in the white list.
I could visit the website from web browser or by the java.net.http package with the below code:
HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create("https://mywebsite/route"))
.GET() // GET is default
.build();
HttpResponse<Void> response = client.send(request,
HttpResponse.BodyHandlers.discarding());
But if I replaced the code with a Vertx implementation from io.vertx.ext.web.client package, I got a 403 forbidden response from the same website.
WebClientOptions options = new WebClientOptions().setTryUseCompression(true).setTrustAll(true);
HttpRequest<Buffer> request = WebClient.create(vertx, options)
.getAbs("https://mywebsite/route")
.ssl(true).putHeaders(headers);
request.send(asyncResult -> {
if (asyncResult.succeeded()) {
HttpResponse response = asyncResult.result();
}
});
Does anyone have an idea why the Vertx implementation is rejected?

Answer 1

Finally got the root cause. I started a local server that accepts the testing request and forwards it to the server on AWS. The testing client sent the request to localhost and thus "Host=localhost:8080/..." is in the request header. In the Vert.X implementation, a new header entry "Host=localhost:443/..." is wrongly put into the request headers. I haven't debug the Vert.X implementation so I have no idea why it behaviors as this. But then the AWS firewall rejected the request with a rule that a request could not come from localhost.