feat:(conn): add RemoteAddr and LocalAddr method

[kehiy]

• Fixes Remote address #489

[kehiy]

@mafredri hi, can you kindly review this, please?

[mafredri]

Except for the suggestion inline, the PR looks good. Thanks.

I would be interested in knowing what your use-case is though, how is this feature beneficial to you?

[kehiy]

@mafredri about use case, several programs need to collect IP address sometimes to use it for spam protection and this kind of stuff. sometimes we have to be aware of who we are talking too. or use it in logs to check whats going on better. in my case we are developing a nostr relay which can be aimed for spam attacks a lot.

[kehiy]

@mafredri can you review again please?

[mafredri]

Since we're adding RemoteAddr() net.Addr, I think it would make sense to add LocalAddr() net.Addr too, do you want to include that in this PR?

[kehiy]

@mafredri so, based on your review, i found that we have a netConn as well which i didn't saw it before. so this one is good. to achieve what you say in reviews we have 3 ways:

1. keeping netConn in Conn struct.
2. keeping RemoteAddr and/or LocalAddr in Conn struct.
3. change rwc in Conn to keep the netConn.

which one makes sense in our case?

[kehiy]

Since we're adding RemoteAddr() net.Addr, I think it would make sense to add LocalAddr() net.Addr too, do you want to include that in this PR?

i would include it in this pr.

[mafredri]

You can just do a similar check as done here:

websocket/netconn_notjs.go

Lines 8 to 20 in 6c8e3ab

	func (nc *netConn) RemoteAddr() net.Addr {
	if unc, ok := nc.c.rwc.(net.Conn); ok {
	return unc.RemoteAddr()
	}
	return websocketAddr{}
	}
	func (nc *netConn) LocalAddr() net.Addr {
	if unc, ok := nc.c.rwc.(net.Conn); ok {
	return unc.LocalAddr()
	}
	return websocketAddr{}
	}

While you're at it, the linked code can be changed to just return nc.c.RemoteAddr(), etc.

We should also add these methods to the WASM implementation too, even if we can't return any useful information.

[kehiy]

@mafredri now both are added based on what you suggest. adding to wasm implementation is remained correct? should it be included in this pr? i need to look at wasm implementation to find out how can i do that.