OAuthの実装(舞台裏)

var crypto = require("crypto");

var Evil = new Object();

const NONCE_CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";

Evil.getNonce = function (charsLength) {
	var result = new String();
	
	for (var i = 0; i < charsLength; i++) {
		var randomNumber = this.getRandom(NONCE_CHARS.length);
		result += NONCE_CHARS.charAt(randomNumber);
	}
	
	return result;
}

Evil.getRandom = function (maxVal) {
	return Math.floor(Math.random() * maxVal);
}

const REPLACE_MAP = {
	"!": "%21",
	"'": "%27",
	"(": "%28",
	")": "%29",
	"*": "%2A"
}

Evil.escapeChars = function (str) {
	var result = new String();

	if (!str) {
		return result;
	}
	
	result = encodeURIComponent(str);
	
	for (var origin in REPLACE_MAP) {
		var destination = REPLACE_MAP[origin];
		result = result.replaceAll(origin, destination);
	}
	
	return result;
}

Evil.generateSignature = function (protocol, url, parameter, consumerSecret, tokenSecret) {
	var result = new String();
	
	var e_protocol = this.escapeChars(protocol);
	var e_url = this.escapeChars(url);
	var e_parameter = this.escapeChars(parameter);
	var key = consumerSecret + "&" + tokenSecret;

	var jointed = e_protocol + "&" + e_url + "&" + e_parameter;

	var hmac = crypto.createHmac("sha1", key);
	hmac.update(jointed);
	digest = hmac.digest("base64");

	result = this.escapeChars(digest);

	return result;
}

Evil.generateParameter = function (parameters) {
	var result = new String();
	
	var keys = new Array();
	for (var key in parameters) {
		keys.push(key);
	}
	keys.sort();
	
	for (var index in keys) {
		var key = keys[index];
		result += key + "=" + parameters[key] + "&"
	}
	
	result = result.substring(0, result.length - 1);
	
	return result;
}

Evil.getTimestamp = function () {
	var result = new Number();
	result = parseInt((new Date)/1000);
	
	return result;
}

global.Evil = Evil;

String.prototype.replaceAll = function (origin, destination) {
	var result = new String();
	result = this.split(origin).join(destination);
	return result;
}