GlassFish 3 - 400 Bad Request on GET/POST/PUT/DELETE

Question

In a script I have, I've created a small and simple REST client. The script itself is a prototype, and therefore the code is not 'production worthy' - so ignore lazy catch expressions and alike.

There are two types of servers that contain the REST service that I fetch data from; either a WildFly 8.2.0 or a GlassFish 3.1.2.2. And the catch here is: My REST client works fine for fetching data from the Wildfly server, but the GlassFish server returns an HTTP 400 Bad Request, for any request.

I can access the REST service for both servers through a web browser, so I know that they are both working properly. I can even do a raw connection though a socket to both servers and they response with the correct data.

So, what could be the reason for GlassFish to not accept the requests?

Socket connection (for testing)

import java.net.Socket;

Socket s = new Socket("localhost", 8080);
String t = "GET /rest/appointment/appointments/search/?fromDate=2016-11-21&branchId=3 HTTP/1.1\nhost: localhost:8080\nAuthorization: Basic base64encodedUsername:PasswordHere\n\n"
OutputStream out = s.getOutputStream();
out.write(t.getBytes());

InputStream inn = s.getInputStream();
Scanner scan = new Scanner(inn);
String line;
while ((line = scan.nextLine()) != null) {
    println line;
}
s.close();

REST client code:

import groovy.json.JsonSlurper;
import javax.xml.bind.DatatypeConverter;


/*
REST-client (a very simple one)
*/
public class RESTclient {
  public static Object get(URL url, Map<String, String> headers) {
    return http(url, "GET", null, headers);
  }
  public static Object post(URL url, String data, Map<String, String> headers) {
    return http(url, "POST", data, headers);
  }

  public static Object put(URL url, String data, Map<String, String> headers) {
    return http(url, "PUT", data, headers);
  }

  public static Object delete(URL url, String data, Map<String, String> headers) {
    return http(url, "DELETE", data, headers);
  }

  private static Object http(URL url, String method, String data, Map<String, String> headers) {
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    Authenticator.setDefault(new Authenticator() {
      protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("username", "password".toCharArray());
      }
    });
    connection.setRequestMethod(method);

    for (String header : headers.keySet()) {
      connection.setRequestProperty(header, headers.get(header));
    }

    if (data != null) {
      connection.setRequestProperty("Content-Type", "application/json");
      connection.setDoOutput(true);
      OutputStream outputStream =connection.getOutputStream();
      outputStream.write(data.getBytes());
    }

    int responseCode = connection.getResponseCode();
    switch (responseCode) {
      case HttpURLConnection.HTTP_NO_CONTENT:
        // This happens when the server doesn't give back content, but all was ok.
        return (new HashMap());
      case HttpURLConnection.HTTP_OK:
        InputStream inputStream = connection.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        String response = reader.readLine();

        JsonSlurper parser = new JsonSlurper();
        Object jsonResponse = parser.parseText(response); // This can be either a List or a Map
        // Close the connection
        try { connection.close(); } catch (Exception e) { /* Already closed */ }
        return jsonResponse;
      default:
        println "response code: " + responseCode;
        println connection.getResponseMessage();
        println connection.getHeaderFields();
        // Close the connection
        try { connection.close(); } catch (Exception e) { /* Already closed */ }
        return null;
    }
  }
}

Usage:

URL appointmentSearchURL = new URL("http://localhost:8080/rest/appointment/appointments/search/?fromDate=2016-11-21&branchId=3");
Object response = RESTclient.get(appointmentSearchURL, new HashMap<String, String>());
println response;

All that is printed out:

response code: 400
Bad Request
[null:[HTTP/1.1 400 Bad Request], Server:[GlassFish Server Open Source Edition 3.1.2.2], Connection:[close], Set-Cookie:[rememberMe=deleteMe; Path=/; Max-Age=0; Expires=Tue, 22-Nov-2016 08:43:29 GMT, SSOcookie=2a86cf4b-a772-435a-b92e-f12845dc20a2; Path=/; HttpOnly], Content-Length:[1090], Date:[Wed, 23 Nov 2016 08:43:28 GMT], Content-Type:[text/html], X-Powered-By:[Servlet/3.0 JSP/2.2 (GlassFish Server Open Source Edition 3.1.2.2 Java/Oracle Corporation/1.7)]]
null

Answer 1

I found my answer! So, I will leave this here if any other stumble across the same issue in the future:

There was a missing Accept header, I guess the server-side only accept json content. I have not researched further on why the WildFly server does not response with a 400 bad request, but I suppose WildFly tries to guess/deduce the incoming data.

So the whole issue was resolved by adding the following:

connection.setRequestProperty("Accept", "application/json");