class SF::TcpSocket

• SF::TcpSocket
• SF::Socket
• Reference
• Object

Overview

Specialized socket using the TCP protocol

TCP is a connected protocol, which means that a TCP socket can only communicate with the host it is connected to. It can't send or receive anything if it is not connected.

The TCP protocol is reliable but adds a slight overhead. It ensures that your data will always be received in order and without errors (no data corrupted, lost or duplicated).

When a socket is connected to a remote host, you can retrieve informations about this host with the remote_address and remote_port functions. You can also get the local port to which the socket is bound (which is automatically chosen when the socket is connected), with the local_port function.

Sending and receiving data can use either the low-level or the high-level functions. The low-level functions process a raw sequence of bytes, and cannot ensure that one call to Send will exactly match one call to Receive at the other end of the socket.

The high-level interface uses packets (see SF::Packet), which are easier to use and provide more safety regarding the data that is exchanged. You can look at the SF::Packet class to get more details about how they work.

The socket is automatically disconnected when it is destroyed, but if you want to explicitly close the connection while the socket instance is still alive, you can call disconnect.

Usage example:

# ----- The client -----

# Create a socket and connect it to 192.168.1.50 on port 55001
socket = SF::TcpSocket.new
socket.connect("192.168.1.50", 55001)

# Send a message to the connected host
message = "Hi, I am a client"
socket.send(message.to_slice)

# Receive an answer from the server
buffer = Slice(UInt8).new(1024)
status, received = socket.receive(buffer)
puts "The server said: #{buffer}"

# ----- The server -----

# Create a listener to wait for incoming connections on port 55001
listener = SF::TcpListener.new
listener.listen(55001)

# Wait for a connection
socket = SF::TcpSocket.new
listener.accept(socket)
puts "New client connected: #{socket.remote_address}"

# Receive a message from the client
buffer = Slice(UInt8).new(1024)
status, received = socket.receive(buffer)
puts "The client said: #{buffer}"

# Send an answer
message = "Welcome, client"
socket.send(message.to_slice)

See also: SF::Socket, SF::UdpSocket, SF::Packet

Defined in:

network/obj.cr

Constructors

• .new

  Default constructor

Instance Method Summary

• #connect(remote_address : IpAddress, remote_port : Int, timeout : Time = Time::Zero) : Socket::Status

  Connect the socket to a remote peer

• #disconnect

  Disconnect the socket from its remote peer

• #finalize

  Destructor

• #local_port : UInt16

  Get the port to which the socket is bound locally

• #receive(data : Slice) : Tuple(Socket::Status, Int32)

  Receive raw data from the remote peer

• #receive(packet : Packet) : Socket::Status

  Receive a formatted packet of data from the remote peer

• #remote_address : IpAddress

  Get the address of the connected peer

• #remote_port : UInt16

  Get the port of the connected peer to which the socket is connected

• #send(data : Slice) : Tuple(Socket::Status, Int32)

  Send raw data to the remote peer

• #send(packet : Packet) : Socket::Status

  Send a formatted packet of data to the remote peer

Constructor Detail

Instance Method Detail