setting HTTP Header for angularjs REST calls - angularjs

Question

I'm trying to set a HTTP Header for all my REST calls with following code:
app.factory('authInterceptor', function ($rootScope, $q, $window) {
return {
request: function (config) {
config.headers = config.headers || {};
config.headers.Authorization = '12345678';
return config;
},
response: function (response) {
if (response.status === 401) {
// handle the case where the user is not authenticated
}
return response || $q.when(response);
}
};
});
app.config(function ($httpProvider) {
$httpProvider.interceptors.push('authInterceptor');
});
I currently don't have any authorization enabled on the server.
when I leave out the line "config.headers.Authorization = '12345678';" , then the REST call works well and I get my results. In the JS console I see
GET http://localhost:8080/rest/club/1 [HTTP/1.1 200 OK 7ms]
But when I put this line in to set the Header field, then I see following request in the javascript console
OPTIONS http://localhost:8080/rest/club/1 [HTTP/1.1 200 OK 2ms]
Why does setting Authorization Header change my method from "GET" to "OPTIONS"? And how can I set a custom Header and my request still work?
changing it to
config.headers["X-Testing"] = '12345678';
had the same result.
EDIT:
I tried the answer, I'm setting following HTTP Headers in the server:
response.getHeaders().putSingle("Access-Control-Allow-Origin", "http://localhost");
response.getHeaders().putSingle("Access-Control-Allow-Header", "X-Testing");
response.getHeaders().putSingle("Access-Control-Allow-Methods", "POST, GET, OPTIONS");
response.getHeaders().putSingle("Access-Control-Max-Age", 1728000);
my REST server is running on port 8080, the webserver for the html/JS on port 8000 (initially worked with file://... but moved to a separate webserver because Origin was null)
response.getHeaders().putSingle("Access-Control-Allow-Origin", "*");
or
response.getHeaders().putSingle("Access-Control-Allow-Origin", "http://localhost:8000");
didn't work either.
Must I return any content in the OPTIONS response? I tried 200 OK with the same content as the GET, but I also tried 204 No Content.
2nd EDIT:
here is what firefox sends and receives for the OPTIONS method:

Answer 1

You need to enable CORS in your REST service. As explained in MDN, once you add a custom header, the http protocol specifies performing a preflight,
Preflighted requests
Unlike simple requests (discussed above), "preflighted" requests first
send an HTTP request by the OPTIONS method to the resource on the
other domain, in order to determine whether the actual request is safe
to send. Cross-site requests are preflighted like this since they may
have implications to user data. In particular, a request is
preflighted if:
It uses methods other than GET, HEAD or POST. Also, if POST is used
to send request data with a Content-Type other than
application/x-www-form-urlencoded, multipart/form-data, or text/plain,
e.g. if the POST request sends an XML payload to the server using
application/xml or text/xml, then the request is preflighted. It sets
custom headers in the request (e.g. the request uses a header such as
X-PINGOTHER)
Addition to enabling CORS you also need to add a Access-Control-Allow-Headers header tag to accept your custom header (for the OPTIONS response). This is visible in the MDN Example,
HTTP/1.1 200 OK
Date: Mon, 01 Dec 2008 01:15:39 GMT
Server: Apache/2.0.61 (Unix)
Access-Control-Allow-Origin: http://foo.example
Access-Control-Allow-Methods: POST, GET, OPTIONS
Access-Control-Allow-Headers: X-PINGOTHER
Access-Control-Max-Age: 1728000
Vary: Accept-Encoding
Content-Encoding: gzip
Content-Length: 0
Keep-Alive: timeout=2, max=100
Connection: Keep-Alive
Content-Type: text/plain
UPDATE
As mentioned in the comments, the OPTION response's Access-Control-Allow-Headers is missing the last "s".