Started on node.js+socket.io+mongoDB on the backend for more responsivnes

server/node_modules/mongodb/lib/read_preference.js

@@ -0,0 +1,104 @@
+"use strict";
+
+/**
+ * @fileOverview The **ReadPreference** class is a class that represents a MongoDB ReadPreference and is
+ * used to construct connections.
+ * 
+ * @example
+ * var Db = require('mongodb').Db,
+ *   ReplSet = require('mongodb').ReplSet,
+ *   Server = require('mongodb').Server,
+ *   ReadPreference = require('mongodb').ReadPreference,
+ *   test = require('assert');
+ * // Connect using ReplSet
+ * var server = new Server('localhost', 27017);
+ * var db = new Db('test', new ReplSet([server]));
+ * db.open(function(err, db) {
+ *   test.equal(null, err);
+ *   // Perform a read
+ *   var cursor = db.collection('t').find({});
+ *   cursor.setReadPreference(ReadPreference.PRIMARY);
+ *   cursor.toArray(function(err, docs) {
+ *     test.equal(null, err);
+ *     db.close();
+ *   });
+ * });
+ */
+
+/**
+ * Creates a new ReadPreference instance
+ * 
+ * Read Preferences
+ *  - **ReadPreference.PRIMARY**, Read from primary only. All operations produce an error (throw an exception where applicable) if primary is unavailable. Cannot be combined with tags (This is the default.).
+ *  - **ReadPreference.PRIMARY_PREFERRED**, Read from primary if available, otherwise a secondary.
+ *  - **ReadPreference.SECONDARY**, Read from secondary if available, otherwise error.
+ *  - **ReadPreference.SECONDARY_PREFERRED**, Read from a secondary if available, otherwise read from the primary.
+ *  - **ReadPreference.NEAREST**, All modes read from among the nearest candidates, but unlike other modes, NEAREST will include both the primary and all secondaries in the random selection.
+ *
+ * @class
+ * @param {string} mode The ReadPreference mode as listed above.
+ * @param {object} tags An object representing read preference tags.
+ * @property {string} mode The ReadPreference mode.
+ * @property {object} tags The ReadPreference tags.
+ * @return {ReadPreference} a ReadPreference instance.
+ */ 
+var ReadPreference = function(mode, tags) {
+  if(!(this instanceof ReadPreference))
+    return new ReadPreference(mode, tags);
+  this._type = 'ReadPreference';
+  this.mode = mode;
+  this.tags = tags;
+}
+
+/**
+ * Validate if a mode is legal
+ *
+ * @method
+ * @param {string} mode The string representing the read preference mode.
+ * @return {boolean}
+ */  
+ReadPreference.isValid = function(_mode) {
+  return (_mode == ReadPreference.PRIMARY || _mode == ReadPreference.PRIMARY_PREFERRED
+    || _mode == ReadPreference.SECONDARY || _mode == ReadPreference.SECONDARY_PREFERRED
+    || _mode == ReadPreference.NEAREST
+    || _mode == true || _mode == false || _mode == null);
+}
+
+/**
+ * Validate if a mode is legal
+ *
+ * @method
+ * @param {string} mode The string representing the read preference mode.
+ * @return {boolean}
+ */  
+ReadPreference.prototype.isValid = function(mode) {
+  var _mode = typeof mode == 'string' ? mode : this.mode;
+  return ReadPreference.isValid(_mode);
+}
+
+/**
+ * @ignore
+ */
+ReadPreference.prototype.toObject = function() {
+  var object = {mode:this.mode};
+
+  if(this.tags != null) {
+    object['tags'] = this.tags;
+  }
+
+  return object;
+}
+
+/**
+ * @ignore
+ */
+ReadPreference.PRIMARY = 'primary';
+ReadPreference.PRIMARY_PREFERRED = 'primaryPreferred';
+ReadPreference.SECONDARY = 'secondary';
+ReadPreference.SECONDARY_PREFERRED = 'secondaryPreferred';
+ReadPreference.NEAREST = 'nearest'
+
+/**
+ * @ignore
+ */
+module.exports = ReadPreference;