javascript - Gzip的JavaScript实现(JavaScript implementation of Gzip [closed])

Question

I'm writing a Web application that needs to store JSON data in a small, fixed-size server-side cache via AJAX (think: Opensocial quotas ).

(我正在编写一个Web应用程序，该应用程序需要通过AJAX将JSON数据存储在固定大小的小型服务器端缓存中（请考虑： Opensocial配额 ）。)

I do not have control over the server.

(我无法控制服务器。)

I need to reduce the size of the stored data to stay within a server-side quota, and was hoping to be able to gzip the stringified JSON in the browser before sending it up to the server.

(我需要减小存储数据的大小，以保持在服务器端配额之内，并且希望能够在将字符串化的JSON发送到服务器之前在浏览器中gzip化该字符串化的JSON。)

However, I cannot find much in the way of JavaScript implementations of Gzip.

(但是，我找不到Gzip的JavaScript实现方式。)

Any suggestions for how I can compress the data on the client side before sending it up?

(关于如何在发送之前在客户端上压缩数据的任何建议？)

  ask by David Citron translate from so

Answer 1

Edit There appears to be a better LZW solution that handles Unicode strings correctly at http://pieroxy.net/blog/pages/lz-string/index.html (Thanks to pieroxy in the comments).

(编辑在http://pieroxy.net/blog/pages/lz-string/index.html上似乎有一个更好的LZW解决方案可以正确处理Unicode字符串（感谢注释中的pieroxy）。)

---

I don't know of any gzip implementations, but the jsolait library (the site seems to have gone away) has functions for LZW compression/decompression.

(我不知道任何gzip实现，但是jsolait库 （该站点似乎已消失）具有LZW压缩/解压缩功能。)

The code is covered under the LGPL .

(该代码包含在LGPL中 。)

// LZW-compress a string
function lzw_encode(s) {
    var dict = {};
    var data = (s + "").split("");
    var out = [];
    var currChar;
    var phrase = data[0];
    var code = 256;
    for (var i=1; i<data.length; i++) {
        currChar=data[i];
        if (dict[phrase + currChar] != null) {
            phrase += currChar;
        }
        else {
            out.push(phrase.length > 1 ? dict[phrase] : phrase.charCodeAt(0));
            dict[phrase + currChar] = code;
            code++;
            phrase=currChar;
        }
    }
    out.push(phrase.length > 1 ? dict[phrase] : phrase.charCodeAt(0));
    for (var i=0; i<out.length; i++) {
        out[i] = String.fromCharCode(out[i]);
    }
    return out.join("");
}

// Decompress an LZW-encoded string
function lzw_decode(s) {
    var dict = {};
    var data = (s + "").split("");
    var currChar = data[0];
    var oldPhrase = currChar;
    var out = [currChar];
    var code = 256;
    var phrase;
    for (var i=1; i<data.length; i++) {
        var currCode = data[i].charCodeAt(0);
        if (currCode < 256) {
            phrase = data[i];
        }
        else {
           phrase = dict[currCode] ? dict[currCode] : (oldPhrase + currChar);
        }
        out.push(phrase);
        currChar = phrase.charAt(0);
        dict[code] = oldPhrase + currChar;
        code++;
        oldPhrase = phrase;
    }
    return out.join("");
}