Ruby Socket
Lightweight Introduction
Ruby Socket Class Hierarchy
To know the socket hierarchy in ruby here a simple tree explains it.
IO # The basis for all input and output in Ruby
└── BasicSocket # Abstract base class for all socket classes
├── IPSocket # Super class for protocols using the Internet Protocol (AF_INET)
│ ├── TCPSocket # Class for Transmission Control Protocol (TCP) sockets
│ │ ├── SOCKSSocket # Helper class for building TCP socket servers applications
│ │ └── TCPServer # Helper class for building TCP socket servers
│ └── UDPSocket # Class for User Datagram Protocol (UDP) sockets
├── Socket # Base socket class that mimics that BSD Sockets API. It provides more operating system specific functionality
└── UNIXSocket # Class providing IPC using the UNIX domain protocol (AF_UNIX)
└── UNIXServer # Helper class for building UNIX domain protocol socket servers
I'll verbosely mention some of Socket::Constants here since I didn't find an obvious reference listing it except Programming Ruby1.9 The Pragmatic Programmers' Guide; Otherwise you've to ri Socket::Constants from command line which is a good way to get the description of each constant.
Socket Types
- SOCK_RAW
- SOCK_PACKET
- SOCK_STREAM
- SOCK_DRAM
- SOCK_RDM
- SOCK_SEQPACKET
Address Families(Socket Domains)
- AF_APPLETALK
- AF_ATM
- AF_AX25
- AF_CCITT
- AF_CHAOS
- AF_CNT
- AF_COIP
- AF_DATAKIT
- AF_DEC
- AF_DLI
- AF_E164
- AF_ECMA
- AF_HYLINK
- AF_IMPLINK
- AF_INET(IPv4)
- AF_INET6(IPv6)
- AF_IPX
- AF_ISDN
- AF_ISO
- AF_LAT
- AF_LINK
- AF_LOCAL(UNIX)
- AF_MAX
- AF_NATM
- AF_NDRV
- AF_NETBIOS
- AF_NETGRAPH
- AF_NS
- AF_OSI
- AF_PACKET
- AF_PPP
- AF_PUP
- AF_ROUTE
- AF_SIP
- AF_SNA
- AF_SYSTEM
- AF_UNIX
- AF_UNSPEC
Socket Protocol
- IPPROTO_SCTP
- IPPROTO_TCP
- IPPROTO_UDP
Protocol Families
- PF_APPLETALK
- PF_ATM
- PF_AX25
- PF_CCITT
- PF_CHAOS
- PF_CNT
- PF_COIP
- PF_DATAKIT
- PF_DEC
- PF_DLI
- PF_ECMA
- PF_HYLINK
- PF_IMPLINK
- PF_INET
- PF_INET6
- PF_IPX
- PF_ISDN
- PF_ISO
- PF_KEY
- PF_LAT
- PF_LINK
- PF_LOCAL
- PF_MAX
- PF_NATM
- PF_NDRV
- PF_NETBIOS
- PF_NETGRAPH
- PF_NS
- PF_OSI
- PF_PACKET
- PF_PIP
- PF_PPP
- PF_PUP
- PF_ROUTE
- PF_RTIP
- PF_SIP
- PF_SNA
- PF_SYSTEM
- PF_UNIX
- PF_UNSPEC
- PF_XTP
Socket options
- SO_ACCEPTCONN
- SO_ACCEPTFILTER
- SO_ALLZONES
- SO_ATTACH_FILTER
- SO_BINDTODEVICE
- SO_BINTIME
- SO_BROADCAST
- SO_DEBUG
- SO_DETACH_FILTER
- SO_DONTROUTE
- SO_DONTTRUNC
- SO_ERROR
- SO_KEEPALIVE
- SO_LINGER
- SO_MAC_EXEMPT
- SO_NKE
- SO_NOSIGPIPE
- SO_NO_CHECK
- SO_NREAD
- SO_OOBINLINE
- SO_PASSCRED
- SO_PEERCRED
- SO_PEERNAME
- SO_PRIORITY
- SO_RCVBUF
- SO_RCVLOWAT
- SO_RCVTIMEO
- SO_RECVUCRED
- SO_REUSEADDR
- SO_REUSEPORT
- SO_SECURITY_AUTHENTICATION
- SO_SECURITY_ENCRYPTION_NETWORK
- SO_SECURITY_ENCRYPTION_TRANSPORT
- SO_SNDBUF
- SO_SNDLOWAT
- SO_SNDTIMEO
- SO_TIMESTAMP
- SO_TIMESTAMPNS
- SO_TYPE
- SO_USELOOPBACK
- SO_WANTMORE
- SO_WANTOOBFLAG
Creating Socket Template
Socket.new(domain, socktype [, protocol])
domain(Address/Protocol Families): like AF_INET, PF_PACKET, etc
socktype: like SOCK_RAW, SOCK_STREAM
protocol: by default, it's 0m it should be a protocol defined (we'll manipulate that later)
TCP Socket
Server/Client life cycle
Client Server
| |
socket + + socket
| |
connect +--------, + bind
| | |
write ,--> +------, | + listen
| | | | |
read `----+ <--, | `-> + accept
| | | |
close +--, | `----> + <--, read <--,
| | | | |
| `--------+----' write ٨
| |
`----->------>------->----`
General Socket usage
Get List of local IPaddreses
require 'socket'
Socket.ip_address_list
Get Hostname
Socket.gethostname
TCP Server
Here we'll represent an absolute TCP server. This server will access connect from one client and send a message to it once connected then close the client and server connection
require 'socket'
server = TCPServer.new('0.0.0.0', 9911) # Server, binds/listens all interfaces on port 9911
client = server.accept # Wait for client to connect
rhost = client.peeraddr.last # peeraddr, returns remote [address_family, port, hostname, numeric_address(ip)]
client.puts "Hi TCP Client! #{rhost}" # Send a message to the client once it connect
client.gets.chomp # Read incoming message from client
client.close # Close the client's connection
server.close # Close the TCP Server
TCP Client
require 'socket'
client = TCPSocket.new('127.0.0.1', 9911) # Client, connects to server on port 9911
rhost = client.peeraddr.last # Get the remote server's IP address
client.gets.chomp
client.puts "Hi, TCP Server #{rhost}"
client.close
You can put timeout/time interval for current connection in-case the server's response get delayed and the socket is still open.
timeval = [3, 0].pack("l_2") # Time interval 3 seconds
client.setsockopt Socket::SOL_SOCKET, Socket::SO_RCVTIMEO, timeval # Set socket receiving time interval
client.setsockopt Socket::SOL_SOCKET, Socket::SO_SNDTIMEO, timeval # Set socket sending time interval
client.getsockopt(Socket::SOL_SOCKET, Socket::SO_RCVTIMEO).inspect # Optional, Check if socket option has been set
client.getsockopt(Socket::SOL_SOCKET, Socket::SO_SNDTIMEO).inspect # Optional, Check if socket option has been set
There are some alternatives for puts and gets methods.You can see the difference and its classes using method method in Pry interpreter console
>> s = TCPSocket.new('0.0.0.0', 9911)
=> #<TCPSocket:fd 11>
>> s.method :puts
=> #<Method: TCPSocket(IO)#puts>
>> s.method :write
=> #<Method: TCPSocket(IO)#write>
>> s.method :send
=> #<Method: TCPSocket(BasicSocket)#send>
>> s = TCPSocket.new('0.0.0.0', 9911)
=> #<TCPSocket:fd 11>
>> s.method :gets
=> #<Method: TCPSocket(IO)#gets>
>> s.method :read
=> #<Method: TCPSocket(IO)#read>
>> s.method :recv
=> #<Method: TCPSocket(BasicSocket)#recv>
UDP Socket
UDP Server
require 'socket'
server = UDPSocket.new # Start UDP socket
server.bind('0.0.0.0', 9911) # Bind all interfaces to port 9911
mesg, addr = server.recvfrom(1024) # Receive 1024 bytes of the message and the sender IP
server puts "Hi, UDP Client #{addr}", addr[3], addr[1] # Send a message to the client
server.recv(1024) # Receive 1024 bytes of the message
UDP Client
require 'socket'
client = UDPSocket.new
client.connect('localhost', 9911) # Connect to server on port 991
client.puts "Hi, UDP Server!", 0 # Send message
server.recv(1024) # Receive 1024 bytes of the server message
There alternative for sending and receiving too, figure it out, RubyDoc.
GServer
GServer standard library implements a generic server, featuring thread pool management, simple logging, and multi-server management. Any kind of application-level server can be implemented using this class:
- It accepts multiple simultaneous connections from clients
- Several services (i.e. one service per TCP port)
- can be run simultaneously,
- can be stopped at any time through the class method
GServer.stop(port)
- All the threading issues are handled
- All events are optionally logged
- Very basic GServer
require 'gserver'
class HelloServer < GServer # Inherit GServer class
def serve(io)
io.puts("What's your name?")
line = io.gets.chomp
io.puts "Hi, #{line}!"
self.stop if io.gets =~ /shutdown/ # Stop the server if you get shutdown string
end
end
server = HelloServer.new(1234, '0.0.0.0') # Start the server on port 1234
server.audit = true # Enable logging
server.start # Start the service
server.join