使用node.js下载大文件，避免占用大量内存

我将回调更改为：

request.addListener('response', function (response) {        var downloadfile = fs.createWriteStream(filename, {'flags': 'a'});        sys.puts("File size " + filename + ": " + response.headers['content-length'] + " bytes.");        response.addListener('data', function (chunk) { dlprogress += chunk.length; downloadfile.write(chunk, encoding='binary');        });        response.addListener("end", function() { downloadfile.end(); sys.puts("Finished downloading " + filename);        });    });

这工作得很好。