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nodejs实用示例：缩址还原

nodejs最近好红火，我也趁寒冷天气在nodejs的火炉边取暖一下。

First published on December 27, 2010, updated on June 18, 2026

2 minutes reading time, 300 words

nodejs实用示例：缩址还原

nodejs最近好红火，我也趁寒冷天气在nodejs的火炉边取暖一下。

思路非常简单:

httpserver获取需要还原的url；
使用httpclient递归请求这个url，直到发现http status not in (302, 301)为止。
返回还原的原url。

好吧，代码如下：

var net = require("net"),
  http = require("http"),
  url = require("url"),
  fs = require("fs");

var DEFAULT_PORTS = {
  "http:": 80,
  "https:": 443,
};

var INDEX_TPL = fs.readFileSync("index.html");

function _write(str, res, content_type) {
  if (res.jsonp_cb) {
    str = res.jsonp_cb + '("' + str + '")';
  }
  res.writeHead(200, {
    "Content-Length": str.length,
    "Content-Type": content_type || "text/plain",
  });
  res.end(str);
}

function expand(short_url, res) {
  var info = url.parse(short_url);
  //  console.log('info: ' + JSON.stringify(info));
  if (info.protocol != "http:") {
    // 无法请求https的url?
    _write(short_url, res);
    return;
  }
  var client = http.createClient(info.port || DEFAULT_PORTS[info.protocol], info.hostname);
  var path = info.pathname || "/";
  if (info.search) {
    path += info.search;
  }
  var headers = {
    host: info.hostname,
    "User-Agent": "NodejsSpider/1.0",
  };
  var request = client.request("GET", path, headers);
  request.end();
  request.on("response", function (response) {
    if (response.statusCode == 302 || response.statusCode == 301) {
      expand(response.headers.location, res);
    } else {
      _write(short_url, res);
    }
  });
}

//expand('http://sinaurl.cn/hbMUII');
// http服务
http
  .createServer(function (req, res) {
    if (req.url.indexOf("/api?") == 0) {
      var params = url.parse(req.url, true);
      if (params.query && params.query.u) {
        if (params.query.cb) {
          // 支持jsonp跨域请求
          res.jsonp_cb = params.query.cb;
        }
        expand(params.query.u, res);
      } else {
        _write("", res);
      }
    } else {
      _write(INDEX_TPL, res, "text/html");
    }
  })
  .listen(1235);

process.on("uncaughtException", function (err) {
  console.log("Caught exception: " + err);
});