Enabling Http2Stream in koa2 app

Question

I7m trying to create a simple http2 server and want to make use of Http2Stream in the http2 module to push large assets. How can I incorporate it in my Koa2 app? currently my server is just a middleware that receives the ctx and next object and checks if the file exists and tries to send it out.

async server(ctx, next, ...arg){
    //check if file exists
    //if it exists, set the headers and mimetype and send file
}

Does the ctx object contain the functions needed to work with http2stream, or how can i extend it?

Answer 1

You can utilize the stream in ctx.res (which is the original node response) like so: ctx.res.stream

Working example: Koa2 with http/2 - this one gets a file in the public folder (filename ist hardcoded here) and sends it through the stream (which then should be the http2stream). Just type https://localhost:8080/file in your browser. You need to place a file thefile.html in to ./public:

'use strict';
const fs = require('fs');
const http2 = require('http2');
const koa = require('koa');

const app = new koa();

const options = {
    key: fs.readFileSync('./key.pem'),
    cert: fs.readFileSync('./cert.pem'),
    passphrase: 'test'
};

function getFile(path) {
    const filePath = `${__dirname}/public/${path}`;
    try {
        const content = fs.openSync(filePath, 'r');
        const contentType = 'text/html';
        return {
            content,
            headers: {
                'content-type': contentType
            }
        };
    } catch (e) {
        return null;
    }
}

// response
app.use(ctx => {
    if (ctx.request.url === '/file') {
        const file = getFile('thefile.html');
        ctx.res.stream.respondWithFD(file.content, file.headers);
    } else {
        ctx.body = 'OK' ;
    }
});

const server = http2.createSecureServer(options, app.callback());
console.log('Listening on port 8080');
server.listen(8080);

Hope that helps