Differentiate between app calls to $http and Angular's requests for static resources in interceptor

Question

With AngularJS interceptors, is it possible to differentiate my app calls to $http (direct either through $resource) from requests made by Angular itself for static resources, like views, without checking URLs?

I'm adding custom authorization header in HTTP interceptor like this:

transparentAuthServices.factory('authHttpInterceptor',
  function (localSessionStorage) {
    return {
      'request': function (config) {
        if (!config.ignoreAuthInterceptor && localSessionStorage.hasSession()) {
          var sessionId = localSessionStorage.getSession().sessionId;
          config.headers['Authorization'] = 'ARTAuth sessionId="' + sessionId + '"';
          return config;
        } else {
          return config;
        }
      }
    }
  };
});

It works fine but I don't need authorization for static resources and my server doesn't check them. I could check URLs and skip on those starting with '/app' (in my case) but I wonder is there an elegant solution?

Answer 1

My experiments showed that in case of requests for templates, the config object has a cache property, and a call to config.cache.info() will return an object:

{id: "templates", size: 7}

This is probably the only reliable way to do it without inspecting the URL.

I also tried inspecting stack traces, but with no success - hard to find any reasonable pattern, and it certainly shouldn't be relied upon.

Still in my opinion the best way is to check the URL.

Answer 2

A quick bit of inspection led me to hypothesize that template requests are made with an Accept header of text/html which lets you get round them quickly. Lots of plugins don't seem to obey that for loading templates but a few indexOf's on the url may clean that up for you. My example:

$httpProvider.interceptors.push(function () {
            return {
                request: function(config) {
                    if (config.url.indexOf('http') != 0
                        && config.headers.Accept !== 'text/html' /* Excludes template requests */
                        && config.url.indexOf('html') === -1 /* some plugins do requests with html */
                        && config.url.indexOf('tpl') === -1 /* match any template naming standards */) {
                        if (config.url.indexOf('/') == 0) {
                            config.url = apiEndpoint + config.url;
                        } else {
                            config.url = apiEndpoint + '/' + config.url;
                        }
                    }

                    return config;
                }
            }
        });