In my project, I am trying to do HTTP/2 Server Push as Zeit support HTTP/2.
So, I added the necessary link header to my request.
But when I am checking the network tab, the initiator is showing as Other instead of Push/Other.
Then I checked another site: https://http2-server-push-demo.keksi.io/ and here Push is clearly showing.
What is going on here? I am not understanding. I am using Now CLI v16.4.4. Can anyone help?
Some debug info
Just in case it is needed here are some command outputs:
Command: curl --http2 -v https://example.com
curl --http2 -v https://ccrewards.in
* Rebuilt URL to: https://ccrewards.in/
* Trying 13.234.90.190...
* TCP_NODELAY set
* Connected to ccrewards.in (13.234.90.190) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
* CAfile: /etc/ssl/certs/ca-certificates.crt
CApath: /etc/ssl/certs
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Client hello (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use h2
* Server certificate:
* subject: CN=ccrewards.in
* start date: Oct 25 06:44:21 2019 GMT
* expire date: Jan 23 06:44:21 2020 GMT
* subjectAltName: host "ccrewards.in" matched cert's "ccrewards.in"
* issuer: C=US; O=Let's Encrypt; CN=Let's Encrypt Authority X3
* SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x7fffe6a71b70)
> GET / HTTP/2
> Host: ccrewards.in
> User-Agent: curl/7.58.0
> Accept: */*
>
* Connection state changed (MAX_CONCURRENT_STREAMS updated)!
< HTTP/2 200
< content-type: text/html; charset=utf-8
< link: </css/bootstrap.min.css>; rel=preload; as=style, </css/placeholder-loading.min.css>; rel=preload; as=style
< date: Mon, 28 Oct 2019 18:06:54 GMT
< vary: User-Agent, Accept-Encoding
< content-encoding: gzip
< content-length: 28149
< etag: "4eadf-E5nKTWVXCBjTRiqdEed4eCgcd6A"
< accept-ranges: none
< cache-control: public, max-age=0, must-revalidate
< x-now-cache: STALE
< x-now-trace: bom1
< server: now
< x-now-id: bom1:bom1:48cbv-1572288058858-8bf8eca0e432
< strict-transport-security: max-age=63072000
<
Warning: Binary output can mess up your terminal. Use "--output -" to tell
Warning: curl to output it to your terminal anyway, or consider "--output
Warning: <FILE>" to save to a file.
* Failed writing body (0 != 15963)
* Connection #0 to host ccrewards.in left intact
Just because a server supports HTTP/2 does not mean it supports all features of HTTP/2. And even if it does, it doesn't mean it initiates push with the link header - that is not defined in the HTTP/2 spec but is a method many (but not all) servers use to initiate HTTP/2 push.
Checking out your site with nghttp (better than curl for HTTP/2 debugging), I cannot see the frames being pushed and from the server.
I'm not familair with Zeit-now but a quick Google suggests it might be built on top of Node which does not support link headers as a method of Push and instead you must use http2stream.pushStream to explicitly initiate an HTTP/2 push.