Auth Adapters refactoring (#3177)

* Moves all authentication providers to Adapter/Auth

* refactors specs

* Deprecates oauth option in favor of auth option

- Deprecates facebookAppIds option (in favor of auth.facebook.appIds)
- Adds warnings about the deprecated options

* nits

src/Adapters/Auth/twitter.js

@@ -0,0 +1,53 @@
+// Helper functions for accessing the twitter API.
+var OAuth = require('./OAuth1Client');
+var Parse = require('parse/node').Parse;
+var logger = require('../../logger').default;
+
+// Returns a promise that fulfills iff this user id is valid.
+function validateAuthData(authData, options) {
+  options = handleMultipleConfigurations(authData, options);
+  var client = new OAuth(options);
+  client.host = "api.twitter.com";
+  client.auth_token = authData.auth_token;
+  client.auth_token_secret = authData.auth_token_secret;
+
+  return client.get("/1.1/account/verify_credentials.json").then((data) => {
+    if (data && data.id_str == ''+authData.id) {
+      return;
+    }
+    throw new Parse.Error(
+      Parse.Error.OBJECT_NOT_FOUND,
+      'Twitter auth is invalid for this user.');
+  });
+}
+
+// Returns a promise that fulfills iff this app id is valid.
+function validateAppId() {
+  return Promise.resolve();
+}
+
+function handleMultipleConfigurations(authData, options) {
+  if (Array.isArray(options)) {
+    let consumer_key = authData.consumer_key;
+    if (!consumer_key) {
+      logger.error('Twitter Auth', 'Multiple twitter configurations are available, by no consumer_key was sent by the client.');
+      throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Twitter auth is invalid for this user.');
+    }
+    options = options.filter((option) => {
+      return option.consumer_key == consumer_key;
+    });
+
+    if (options.length == 0) {
+      logger.error('Twitter Auth','Cannot find a configuration for the provided consumer_key');
+      throw new Parse.Error(Parse.Error.OBJECT_NOT_FOUND, 'Twitter auth is invalid for this user.');
+    }
+    options = options[0];
+  }
+  return options;
+}
+
+module.exports = {
+  validateAppId,
+  validateAuthData,
+  handleMultipleConfigurations
+};