Question

I am trying to read the authorization header for an HTTP request (because I need to add something to it), but I always get null for the header value. Other headers work fine.

public void testAuth() throws MalformedURLException, IOException{
    URLConnection request = new URL("http://google.com").openConnection();
    request.setRequestProperty("Authorization", "MyHeader");
    request.setRequestProperty("Stackoverflow", "anotherHeader");
    // works fine
    assertEquals("anotherHeader", request.getRequestProperty("Stackoverflow"));
    // Auth header returns null
    assertEquals("MyHeader", request.getRequestProperty("Authorization"));
}

Am I doing something wrong? Is this a “security” feature? Is there a way to make this work with URLConnection, or do I need to use another HTTP client library?

Answer 1

Apparently, it’s a security “feature”. The URLConnection is actually an instance of sun.net.www.protocol.http.HttpURLConnection. It defines getRequestProperty as:

    public String getRequestProperty (String key) {
        // don't return headers containing security sensitive information
        if (key != null) {
            for (int i=0; i < EXCLUDE_HEADERS.length; i++) {
                if (key.equalsIgnoreCase(EXCLUDE_HEADERS[i])) {
                    return null;
                }
            }
        }
        return requests.findValue(key);
    }

The EXCLUDE_HEADERS array is defined as:

   // the following http request headers should NOT have their values
   // returned for security reasons.
   private static final String[] EXCLUDE_HEADERS = {
           "Proxy-Authorization",
           "Authorization"
   };