Question

我一直在尝试使用快速应用程序将响应作为流发送。

var Readable = require('stream').Readable;
var rs = Readable();


app.get('/report', function(req,res) {

    res.statusCode = 200;
    res.setHeader('Content-type', 'application/csv');
    res.setHeader('Access-Control-Allow-Origin', '*');

    // Header to force download
    res.setHeader('Content-disposition', 'attachment; filename=Report.csv');


    rs.pipe(res);

    rs.push("USERID,NAME,FBID,ACCOUNT,SUBSCRIPTION,PRICE,STATE,TIMEPERIOD\n");

    for (var i = 0; i < 10; i++) {
        rs.push("23,John Doe,1234,500,SUBSCRIPITON,100,ACTIVE,30\n");
    }

    rs.push(null);
});

当我用“rs.pipe（process.stdout）”替换“rs.pipe（res）”时，它会在控制台中打印，但是如何使它在Express应用程序中运行。

Error: not implemented
    at Readable._read (_stream_readable.js:465:22)
    at Readable.read (_stream_readable.js:341:10)
    at Readable.on (_stream_readable.js:720:14)
    at Readable.pipe (_stream_readable.js:575:10)
    at line "rs.pipe(res);"

Answer 1

您不需要可读的流实例，只需使用res.write()：

res.write("USERID,NAME,FBID,ACCOUNT,SUBSCRIPTION,PRICE,STATE,TIMEPERIOD\n");

for (var i = 0; i < 10; i++) {
    res.write("23,John Doe,1234,500,SUBSCRIPITON,100,ACTIVE,30\n");
}

res.end();

这是有效的，因为在Express中，res基于节点自己的http.serverResponse，因此它会继承其所有方法（例如write）。

Answer 2

我能够做到这一点。

将此代码放在您的Express路由器中。
打开网络浏览器
转到http://yourdomain/yourrouterpath/stream

...

router.get('/stream', function (req, res, next) {
  //when using text/plain it did not stream
  //without charset=utf-8, it only worked in Chrome, not Firefox
  res.setHeader('Content-Type', 'text/html; charset=utf-8');
  res.setHeader('Transfer-Encoding', 'chunked');

  res.write("Thinking...");
  sendAndSleep(res, 1);
});


var sendAndSleep = function (response, counter) {
  if (counter > 10) {
    response.end();
  } else {
    response.write(" ;i=" + counter);
    counter++;
    setTimeout(function () {
      sendAndSleep(response, counter);
    }, 1000)
  };
};

Answer 3

为了使用tar-stream，我需要以快速方式发送响应。这是我的处理方法，以防它对任何人都有帮助。

请求是针对服务器上存储的tar文件中的单个文件。

const fs = require("fs"),
   tar = require("tar-stream");

app.get("/fileFromTar/*", (req, res) => {
   const fileWanted = req.params[0],
      readStream = fs.createReadStream('myTarFile.tar'),
      extractor = tar.extract();

   extractor.on('entry', (header, stream, next) => {
      stream.on('end', next);

      if (header.name === fileWanted) {
         const { size } = header;
         res.set({
           "Content-Type": 'audio/flac', // or whichever one applies
           "Content-Length": size,
           "Content-Range": `bytes 0-${size}/${size}`
         });
         stream.pipe(res);
      }
      else stream.resume();
   });
   readStream.pipe(extractor);
});

我如何在快递中传输响应

3 个答案: