模拟HTTP请求

Question

Im calling a Java App that is called like "http://localhost:32567?test=aaa" trying to send a a text response to a browser that connects. Response I send is like

HTTP/1.1 200 OK
Content-Type: text/xml
Cache-Control: no-cache
Date: Thu Nov 02 15:56:26 NZDT 2017

<?xml version="1.0" ?><root><message>hello world</message><status>OK</status></root>

When I open the page in browser it works fine and but when I call it using AJAX as Post request the HTTP status returned is 0?

this is code im running in the browser

   var http_request = new XMLHttpRequest();
   http_request.overrideMimeType('text/xml');
   http_request.onreadystatechange = function() {
      alert(http_request.readyState + " " + http_request.status);
   };
   http_request.open('POST', "http://localhost:32567?test=aaa", true);
   http_request.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
   http_request.send("");

response i get is

1 0
2 0
4 0

where I expect to get

4 200

The Java Test Code sending the response is as follows

import java.io.*;
import java.net.*;

public class test {
    public test() throws Exception {
        ServerSocket ss = new ServerSocket(32567);

        Socket client = null;
        while ((client = ss.accept()) != null) {
           boolean sentOut = false;
           BufferedWriter out = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
           String output = "HTTP/1.1 200 OK
Content-Type: text/xml
Cache-Control: no-cache
Date: " + (new java.util.Date()) + "

<?xml version=\"1.0\" ?><root><message>test</message><status>OK</status></root>
";
           System.out.println("--------------------------
" +  output);
           out.write(output);
           out.flush();
           out.close();
           client.close();
        }
    }

    public static void main(String args[]) throws Exception {
        new test();
    }
}

Answer 1

As Phil suggested the issue is with CORS. Add a header Access-Control-Allow-Origin: * to the response and the browser is compromised.