Node.js 如何通过管道将 gzip 流传输到 writestream

Question

我似乎无法让它发挥作用。我想将一些数据写入 gzip 流，然后将 gzip 流通过管道传输到文件写入流。我想在文件写入完成后调用一个函数。我目前有：

  var gz = zlib.createGzip()
               .pipe(fs.createWriteStream(gz_path));

  gz.write(data);

  gz.on('error', function(err){
    console.log("wtf error", err);
  });

  gz.on('finish', function(){
    console.log("write stream is done");
    dosomething();
  });

永远不会调用完成事件或错误事件。

Answer 1

尝试

var zlib = require('zlib');
var stream = require('stream');
var util = require('util');
var fs = require('fs');

var gz = zlib.createGzip();

function StringifyStream(){
    stream.Transform.call(this);

    this._readableState.objectMode = false;
    this._writableState.objectMode = true;
}
util.inherits(StringifyStream, stream.Transform);

StringifyStream.prototype._transform = function(obj, encoding, cb){
    this.push(JSON.stringify(obj));
    cb();
};


var data = "some data in here";

var rs = new stream.Readable({ objectMode: true });
rs.push(data);
rs.push(null);


rs.pipe(new StringifyStream())
  .pipe(gz)
  .pipe(fs.createWriteStream('test.gz'))
  .on('error', function(err){
    console.log("wtf error", err);
  })
  .on('finish', function(){
  console.log("write stream is done");
  // dosomething();
});