a better default configuration for TLS connection of http2

[jmuk]

It seems the TLS socket is initialized as tls.connect(port, host, options) in http2.connect. Some existing HTTP2 servers require some TLS options to set up the connection properly. More specifically:

• servername (for Server Name Indication)
• ALPN / NPN, specifying 'h2'

I believe those should be set by defaults, then passing a URL string will just work.

Also, maybe it's better to use secureConnect event instead of connect event for the TLS sockets for setting up a session -- so that it won't go into the session if some TLS setup failure happens.

[jasnell]

The ALPN/NPN bit should already be handled internally by the code. If it's not, then that's definitely a bug. For the SNI, that should be able to be passed in on the options but I haven't tested it yet.

[jmuk]

I think you're talking about the servers, but I was talking about the clients (sorry I wasn't clear).

The http2 client sockets are initialized around https://github.com/nodejs/http2/blob/master/lib/internal/http2/core.js#L1238 but no ALPN/NPN are specified yet, if I understand correctly.

SNI can be specified through options indeed, but (for the clients) I think it's better to specify the host name by default, otherwise an http2 connection request will look like http2.connect("https://http2.golang.org/", {servername: 'http2.golang.org'}) which are really redundant.

[jasnell]

Ok. I'll verify shortly and will make the sni change. Thank you!