我如何在快递中传输响应 [英] How do i stream response in express

问题描述

我一直在尝试使用快速应用程序将响应作为流发送。

I've been trying to get a express app to send the response as stream.

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替换rs.pipe（res）时，它会在控制台中打印。 pipe（process.stdout）但如何使它在快递应用程序中工作。

It does print in the console when i replace "rs.pipe(res)" by "rs.pipe(process.stdout)" but how to make it work in express app.

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);"

推荐答案

您不需要可读的流实例，只需使用 res.write（）：

You don't need a readable stream instance, just use 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 是基于Node自己的 http.serverResponse ，所以它继承了它的所有方法（比如 写 ）。

This works because in Express, res is based on Node's own http.serverResponse, so it inherits all its methods (like write).

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