Add peer_ip and peer_port fields to Conn

[chrismccord]

This PR adds peer_ip, peer_port fields to the Conn. I wasn't sure how to get at the ranch/cowboy request to setup the peer_port, so the test for peer_port currently just asserts that it's a present and valid integer.

[josevalim]

Thanks! What if we just call it peer returning a tuple? And for tests, we always run them using the same port, so you can assert whatever you got there.

[chrismccord]

I split them since my own prior use-case almost always involve grabbing the peer's ip only, but a tuple would be just fine. I'll make the change.

As far as testing, the peer_port actually randomly changes across test runs so I can't reliably check its value.

[josevalim]

Awesome, thanks!

[chrismccord]

The requested changes have been made. Let me know if you would like to see any changes.

[josevalim]

Thanks. I am wondering if we should leave the ip as a tuple or a binary. Do you have any reasoning for choosing one over the other? At first I prefer the tuple because it is already the parsed data but I am not sure.

[ericmj]

@chrismccord Don't forget to add the peer field to record_type.

@josevalim What is the reasoning for not using the parsed tuple? I think we should keep the tuple, it is easier to convert a tuple to binary than the other way around.

[chrismccord]

I like the ip as a tuple since we don't have to do any extra work, like you said. Usability wise, the ways I would use the ip would likely be in string form most of the time, but that's only a single function call to obtain. Perhaps we use a tuple for the ip and provide a helper function to convert the peer to a string ip? This would provide easier conversion access instead of users having to dig into inet and convert to a string. Thoughts?

[josevalim]

This would provide easier conversion access instead of users having to dig into inet and convert to a string.

Sounds like a good plan. How should it be called and where should it be?

Another option is to make it return a Plug.Conn.Peer struct and implement String.Chars for it.

[chrismccord]

I like the idea of the struct/protocol. Would the String.Chars for a Peer just convert the IP to string?

[josevalim]

@chrismccord I would make it return "IP:PORT" but I would also be ok with it returning "IP" only (leaving the port out). However, for now we would need to implement it as a record.

[chrismccord]

I'll get started on this with records and see how it looks

[josevalim]

@chrismccord is there still any interest here? :)

[josevalim]

Closing this, we can always add it back when there is a need. :)