javascriptでcookieを扱うクラスを書いてみた

programming javascript

JavaScriptでクッキーを扱う方法を学習するためにクッキー関係の操作をまとめたクラスを書いてみた。

// cookieWrap.js
/*
 * Firefox3,Google Chromeでのみ動作確認。
 */
function Cookie()
{
    this.initialize.apply(this, arguments);
}

Cookie.prototype = {
    initialize: function()
    {
        this.storage = this.expand();
    },
    // cookie文字列->連想配列
    expand: function()
    {
        if (document.cookie == "")
            return {};
        var hash = {};
        var list = document.cookie.split(";");
        for (var i = 0; i < list.length; i++){
            var pair = list[i].split("=");
            hash[pair[0]] = unescape(pair[1]);
        }
        return hash;
    },
    // 連想配列->cookie文字列
    fold: function()
    {
        var list = [];
        for (var key in this.storage){
            var val = this.storage[key];
            if (key != "expires")
                val = escape(val);
            list.push([key, val].join("="));
        }
        return list.join(";");
    },
    set: function(key, val)
    {
        this.storage[key] = val;
        document.cookie = this.fold();
    },
    get: function(key)
    {
        for (var k in this.storage)
            if (k == key)
                return unescape(this.storage[k]);
        return null;
    },
    dump: function()
    {
        return this.storage;
    },

    //
    // expire関係
    //
    expireFromNow: function(msec)
    {
        var gmts = new Date(new Date().getTime() + msec).toGMTString();
        this.set("expires", gmts);
    },
    expireSecond: function(seconds)
    {
        this.expireFromNow(seconds *1000);
    },
    expireMinite: function(minites)
    {
        this.expireSecond(minites *60);
    },
    expireHour: function(hours)
    {
        this.expireMinite(hours *60);
    },
    expireDay: function(days)
    {
        this.expireHour(days *24);
    },
    expireDate: function(d)
    {
        // 特定の日付時刻にリセット
        this.expireFromNow(datetime.getTime()); 
    },
};

このクラスを使ってカウンタを実装してみた。"you visited N time(s)"と回数が表示される。

<html>
    <head>
        <meta http-equiv="content-type" content="text/html"/>
        <title>cookie counter</title>
        <script src="./cookieWrap.js"></script>
        <script>
function $(tid){ return document.getElementById(tid); }
function main()
{
    var cookie = new Cookie();
    var count = cookie.get("count");
    if (count == null)
        count = 0;
    cookie.set("count", parseInt(count) + 1);
    cookie.expireSecond(10);

    $("container").innerHTML = ["you visit ", cookie.get("count"), " time(s)"].join("");

    //setTimeout("location.reload();", 1000);
}
        </script>
    </head>
    <body onLoad="main();">
        <div id="container"></div>
    </body>
</html>