Julia

Socket address type

Client

A client connects using the Sockets.connect() function. It can then read and write (newline terminated) strings. The client is EchoClient.jl illustrates these:

using Sockets

if size(ARGS)[1] < 1
   println("Usage: IP hostname")
   exit(1)
end

hostname = ARGS[1]

clientside = connect(hostname, 2000)

print("Enter line:")
for line in eachline(stdin)
    print("Read line: '$line'\n")
    if line == "BYE"
       exit(0)
    end
    write(clientside, string(line, "\n"))
    write(stdout, "Echoed: '", readline(clientside, keep=true), "'")

    print("\nEnter line:")
end

It can be run in a number of ways such as

      julia EchoClient.jl localhost
      julia EchoClient.jl 127.0.0.1
  

but not

      julia EchoClient.jl ::1
  

The implementation currently uses getaddrinfo() with the default of IPv4 address only and won't accept a literal IPv6 address.

Multi-threaded server

A server listens to the zero (ANY) address on the port to accept requests. While the socket remains open, it reads the available bytes and writes the resultant vector back to the socket.

The server is EchoServer.jl illustrates these:

using Sockets

server = listen(IPv6(0), 2000)

while true
    sock = accept(server)
    write(stdout, "Connected")
    @async while isopen(sock)
        bytes = readavailable(sock)
	write(sock, bytes)
    end
end

Socket options

Resources

• Sockets
• Networking and Streams
• I/O and Network

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Copyright © Jan Newmarch, jan@newmarch.name

" Network Programming using Java, Go, Python, Rust, JavaScript and Julia" by Jan Newmarch is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License .
Based on a work at https://jan.newmarch.name/NetworkProgramming/ .

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