Is it possible to call Express Router directly from code with a “fake” request?

Question

Tangential to this question, I would like to find out if there is a way of triggering the Express Router without actually going through HTTP?

Answer 1

By going to the source of Express, I was able to find out that there is indeed an API that is just as simple as I wished for. It is documented in the tests for express.Router.

/** 
* @param {express.Router} router 
*/
function dispatchToRouter(router, url, callback) {

    var request = {
        url  : url,
        method : 'GET'
    };

    // stub a Response object with a (relevant) subset of the needed
    // methods, such as .json(), .status(), .send(), .end(), ...
    var response = {
        json : function(results) {
            callback(results);
        }
    };

    router.handle(request, response, function(err) {
        console.log('These errors happened during processing: ', err);
    });
}

But ... the downside is, exactly the reason why it is undocumented in the first place: it is a private function of Router.prototype:

/**
 * Dispatch a req, res into the router.
 * @private
 */

proto.handle = function handle(req, res, out) {
  var self = this;
  ...
}

So relying on this code is not the safest thing in the world.