{Nodejs} 错误 HPE_INVALID_CONSTANT 解决

 http.get(_options.url, function (res) {
        var pageData = "";
        res.setEncoding(_options.encoding);
        res.on(‘error‘, function (err) {
            console.log(err);
        });
        res.on(‘data‘, function (chunk) {
            pageData += chunk;
        });
        res.on(‘end‘, function () {
            var content = pageData;
            callback(content);
        });
    }).on(‘error‘, function (e) {
        console.log(e.message);
        callback(null);
    });

Connection:keep-alive
Content-Encoding:gzip
Content-Type:text/xml
Date:Thu, 08 May 2014 14:43:50 GMT
Server:duomi/1.0.8
Transfer-Encoding:chunked

Connection:keep-alive
Content-Encoding:gzip
Content-Type:application/json
Date:Thu, 08 May 2014 14:37:47 GMT
Server:duomi/1.0.8
Transfer-Encoding:chunked