Change incorrect WebSocket reference to Unix sockets

[Raphexion]

I believe that the reference to WebSockets is incorrect in the book. I think that this is not actually WebSockets but instead a standard Unix socket abstraction.

Normally, WebSockets is a protocol for establishing a two-way communication to a backend webserver (after performing a HTTP upgrade).

In the book, only the normal request and response flow is shown.

[1] https://en.wikipedia.org/wiki/WebSocket
[2] https://en.wikipedia.org/wiki/Berkeley_sockets#Socket_API_functions

Once again, thank you for writing this book.

I assign the copyright of this contribution to Pedro Duarte Faria.

[Raphexion]

I am sorry that I made some extra line ending changes (windows vs unix). I tried multiple ways to get ride of them. You are very welcome to edit my PR.

[pedropark99]

It's okay. I have faced this same issue of windows line endings vs linux multiple times, is really annoying .

[RafaelFigueiredo]

that one term take my attention too, but Unix socket is not quite correct yet.

Unix socket uses a filesystem abstraction like unix:///etc/var/docker.sock to do inter-process communication in the same machine, under the hood the OS maps the file descriptor to a memory address instead of really write to disk, so one process can write and other can read from that address.

What we are looking for is Network Socket, that can be of 3 types:

• stream socket (TCP)
• datagram socket (UDP)
• raw socket - gives you control to build the network packet from scratch, used for protocols such as ICMP and others.

[Raphexion]

@RafaelFigueiredo To be honest, I don't know the correct term. I picked the term Unix socket abstraction because it dates back to the old Unix days. Especially with the flow that is described in the book.

• listen
• accept
• send/recv

But you are probably correct. The word Unix confuses the issue. So probably just socket abstraction or network socket abstraction is better.

[pedropark99]

I decided to go with "TCP socket".