Making a TCP echo server with TCP-IP sockets
In this section, we will set up some foundational packages, then build a basic echo server, followed by a more sophisticated version.
The first version of an echo server
The Sockets package defines all the types (such as IPAddr, IPv4, IPv6, TCPSocket, and UDPSocket) and methods (such as connect, listen, accept, bind, send, and recv) for doing basic network communication in Julia.
Use the Sockets package to make IP addresses like this (see Chapter2\tcp_echoserver\ip_addr_uri.jl):
using Sockets addr = ip"185.43.124.6" # 1 typeof(addr) # 2
Line 1 uses the ip"..." string literal, and line 2 displays IPv4. Let’s connect to a website and get its IP address:
connect("julialang.org", 80) # 3
getaddrinfo("julialang.org") ...
