getRequestProperty(“Authorization”) always returns

问题:

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?

回答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"
   };

回答2:

Have you tried using URLConnection.addRequestProperty()? This is how I use to add HTTP Request Headers.

回答3:

I am not happy about the extra dependencies, but following the suggestion to switch to Commons Http solved the immediate problem for me.

I'd still like to know what the problem was with my original code.