如何以快递方式发送回复? [英] How do I stream response in express?

问题描述

我一直在尝试开发一个快速应用程序，以流的形式发送响应.

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);
});      

当我替换"rs.pipe(res)"时，它确实会在控制台中打印.通过"rs.pipe(process.stdout)".但是如何使其在Express应用程序中起作用?

It does print in the console when I replace "rs.pipe(res)" by "rs.pipe(process.stdout)". But how to make it work in an 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();

之所以可行，是因为在Express中， res 是基于Node自己的>code> http.serverResponse ，因此它继承了其所有方法(例如 write ).

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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