Enabling Http2Stream in koa2 app - node.js

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