Rocket.Chat/packages/rocketchat-ldap/ldap_client.js

// Pass in username, password as normal
// customLdapOptions should be passed in if you want to override LDAP_DEFAULTS
// on any particular call (if you have multiple ldap servers you'd like to connect to)
// You'll likely want to set the dn value here {dn: "..."}
Meteor.loginWithLDAP = function(user, password, customLdapOptions, callback) {
	// Retrieve arguments as array
	var args = [];
	for (var i = 0; i < arguments.length; i++) {
	    args.push(arguments[i]);
	}
	// Pull username and password
	user = args.shift();
	password = args.shift();
	
	// Check if last argument is a function
	// if it is, pop it off and set callback to it
	if (typeof args[args.length-1] == 'function') callback = args.pop(); else callback = null;
	
	// if args still holds options item, grab it
	if (args.length > 0) customLdapOptions = args.shift(); else customLdapOptions = {};

	// Set up loginRequest object
	var loginRequest = _.defaults({
		username: user,
		ldapPass: password
	}, {
		ldap: true,
		ldapOptions: customLdapOptions
	});

	Accounts.callLoginMethod({
		// Call login method with ldap = true
		// This will hook into our login handler for ldap
		methodArguments: [loginRequest],
		userCallback: function(error, result) {
			if (error) {
				callback && callback(error);
			} else {
				callback && callback();
			}
		}
	});
}