node.js – Nodejs二进制http流

这是客户端：

var request = require('request');
var fs = require('fs');

// ...

  var readStream = fs.createReadStream(file.path);
  readStream.on('end',function() {
    that.emit('finished');
  });
  readStream.pipe(request.post(target));

// ...

这是服务器端：

var fs = require('fs');
var path = require('path');

// ...

    app.post('/:filename',function(req,res) {
      req.setEncoding('binary');
      var filename = path.basename(req.params.fileName);
      filename = path.resolve(desTinationDir,fileName);
      var dst = fs.createWriteStream(fileName);
      req.pipe(dst);
      req.on('end',function() {
        res.send(200);
      });
    });

// ...

一切正常,文件在服务器端正确保存……但它们比源文件大50％左右.我试图看到两个文件与hexdump之间的区别,服务器端文件有相似的内容,但有时为0xC2.我想这与编码有关.