Sketch out dynamic configuration middleware.

lib/authenticator.js

@@ -165,6 +165,12 @@ Authenticator.prototype.authenticate = function(strategy, options, callback) {
   return this._framework.authenticate(this, strategy, options, callback);
 };
 
+
+Authenticator.prototype.authenticateWith = function(strategy, options, callback) {
+  return this._framework.authenticateWith(this, strategy, options, callback);
+};
+
+
 /**
  * Middleware that will authorize a third-party account using the given
  * `strategy` name, with optional `options`.

lib/framework/connect.js

@@ -2,7 +2,8 @@
  * Module dependencies.
  */
 var initialize = require('../middleware/initialize')
-  , authenticate = require('../middleware/authenticate');
+  , authenticate = require('../middleware/authenticate')
+  , authenticateWith = require('../middleware/authenticateWith');
 
 /**
  * Framework support for Connect/Express.
@@ -22,7 +23,8 @@ exports = module.exports = function() {
 
   return {
     initialize: initialize,
-    authenticate: authenticate
+    authenticate: authenticate,
+    authenticateWith: authenticateWith
   };
 };
 

lib/middleware/authenticateWith.js

@@ -0,0 +1,39 @@
+/**
+ * Module dependencies.
+ */
+var authenticate = require('./authenticate')
+  , Strategy = require('passport-strategy')
+
+
+module.exports = function authenticateWith(passport, configurator, options, callback) {
+  if (typeof options == 'function') {
+    callback = options;
+    options = {};
+  }
+  options = options || {};
+
+  if (!configurator) { throw new TypeError('passport.authenticateWith middleware requires a configuration function'); }
+
+  return function authenticateWith(req, res, next) {
+
+    function configured(err, method) {
+      if (err) { return next(err); }
+      if (!method) {
+        return next(new Error('Dynamic configuration did not return a valid passport strategy'));
+      }
+
+      return authenticate(passport, method, options, callback)(req, res, next);
+    }
+
+    try {
+      var arity = configurator.length;
+      if (arity == 3) {
+        configurator(req, options, configured);
+      } else { // arity == 2
+        configurator(req, configured);
+      }
+    } catch (ex) {
+      return next(ex);
+    }
+  };
+};