Facebook iframe Canvas App Authentication in node.js

gistfile1.js `� @ V �~�@ V var querystring = require("querystring"); var base64ToString = function(str) { return (new Buffer(str || "", "base64")).toString("ascii"); }; var base64UrlToString = function(str) { return base64ToString( base64UrlToBase64(str) ); }; var base64UrlToBase64 = function(str) { var paddingNeeded = (4- (str.length%4)); for (var i = 0; i < paddingNeeded; i++) { str = str + '=';