class TCPServer

Overview

A Transmission Control Protocol (TCP/IP) server.

Usage example:

require "socket"

def handle_client(client)
  message = client.gets
  client.puts message
end

server = TCPServer.new("localhost", 1234)
while client = server.accept?
  spawn handle_client(client)
end

Options:

  • backlog to specify how many pending connections are allowed;
  • reuse_port to enable multiple processes to bind to the same port (SO_REUSEPORT).

Included Modules

Defined in:

socket/tcp_server.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from module Socket::Server

accept : IO
accept(&) accept
, accept? : IO?
accept?(&) accept?

Instance methods inherited from class TCPSocket

tcp_keepalive_count tcp_keepalive_count, tcp_keepalive_count=(val : Int) tcp_keepalive_count=, tcp_keepalive_idle tcp_keepalive_idle, tcp_keepalive_idle=(val : Int) tcp_keepalive_idle=, tcp_keepalive_interval tcp_keepalive_interval, tcp_keepalive_interval=(val : Int) tcp_keepalive_interval=, tcp_nodelay=(val : Bool) tcp_nodelay=, tcp_nodelay? : Bool tcp_nodelay?

Constructor methods inherited from class TCPSocket

new(family : Family = Family::INET, blocking = false)
new(host, port, dns_timeout = nil, connect_timeout = nil, blocking = false)
new(*, fd : Handle, family : Family = Family::INET, blocking = false) new

Class methods inherited from class TCPSocket

open(host, port, &) open

Instance methods inherited from class IPSocket

bind(addr) bind, close close, connect(addr, timeout = nil, &) connect, local_address : Socket::IPAddress local_address, remote_address : Socket::IPAddress remote_address

Instance methods inherited from class Socket

accept : Socket accept, accept? : Socket? accept?, bind(host : String, port : Int) : Nil
bind(port : Int)
bind(addr : Socket::Address) : Nil bind
, blocking blocking, blocking=(value) blocking=, broadcast=(val : Bool) broadcast=, broadcast? : Bool broadcast?, close_on_exec=(arg : Bool) close_on_exec=, close_on_exec? close_on_exec?, close_read close_read, close_write close_write, closed? : Bool closed?, connect(host : String, port : Int, connect_timeout = nil) : Nil
connect(addr, timeout = nil) : Nil
connect(addr, timeout = nil, &) connect
, family : Family family, fcntl(cmd, arg = 0) fcntl, fd fd, finalize finalize, inspect(io : IO) : Nil inspect, keepalive=(val : Bool) keepalive=, keepalive? keepalive?, linger linger, linger=(val : Int?) linger=, listen(backlog : Int = SOMAXCONN) : Nil
listen(backlog : Int = SOMAXCONN, &) listen
, protocol : Protocol protocol, receive(message : Bytes) : Tuple(Int32, Address)
receive(max_message_size = 512) : Tuple(String, Address) receive
, recv_buffer_size : Int32 recv_buffer_size, recv_buffer_size=(val : Int32) recv_buffer_size=, reuse_address=(val : Bool) reuse_address=, reuse_address? : Bool reuse_address?, reuse_port=(val : Bool) reuse_port=, reuse_port? : Bool reuse_port?, send(message, to addr : Address) : Int32
send(message) : Int32 send
, send_buffer_size : Int32 send_buffer_size, send_buffer_size=(val : Int32) send_buffer_size=, tty? tty?, type : Type type

Constructor methods inherited from class Socket

new(family : Family, type : Type, protocol : Protocol = Protocol::IP, blocking = false)
new(fd, family : Family, type : Type, protocol : Protocol = Protocol::IP, blocking = false) new
, tcp(family : Family, blocking = false) : self tcp, unix(type : Type = Type::STREAM, blocking = false) : self unix

Class methods inherited from class Socket

fcntl(fd, cmd, arg = 0) fcntl, ip?(string : String) ip?, udp(family : Family, blocking = false) udp

Class methods inherited from module Crystal::System::Socket

fcntl(fd, cmd, arg = 0) fcntl

Instance methods inherited from module IO::Evented

evented_close : Nil evented_close, evented_read(slice : Bytes, errno_msg : String, &) : Int32 evented_read, evented_reopen : Nil evented_reopen, evented_send(slice : Bytes, errno_msg : String, &) : Int32 evented_send, evented_write(slice : Bytes, errno_msg : String, &) : Nil evented_write, read_timeout : Time::Span? read_timeout, read_timeout=(read_timeout : Number) : Number
read_timeout=(timeout : Time::Span?) : Time::Span? read_timeout=
, write_timeout : Time::Span? write_timeout, write_timeout=(write_timeout : Number) : Number
write_timeout=(timeout : Time::Span?) : Time::Span? write_timeout=

Instance methods inherited from module IO::Buffered

buffer_size : Int32 buffer_size, buffer_size=(value) buffer_size=, close : Nil close, flush flush, flush_on_newline=(flush_on_newline) flush_on_newline=, flush_on_newline? : Bool flush_on_newline?, peek : Bytes? peek, read(slice : Bytes) : Int32 read, read_buffering=(read_buffering) read_buffering=, read_buffering? : Bool read_buffering?, rewind rewind, sync=(sync) sync=, sync? : Bool sync?, unbuffered_close unbuffered_close, unbuffered_flush unbuffered_flush, unbuffered_read(slice : Bytes) unbuffered_read, unbuffered_rewind unbuffered_rewind, unbuffered_write(slice : Bytes) unbuffered_write, write(slice : Bytes) : Nil write

Instance methods inherited from class IO

<self <<, close close, closed? : Bool closed?, each_byte(&) : Nil
each_byte each_byte
, each_char(&) : Nil
each_char each_char
, each_line(*args, **options, &block : String -> ) : Nil
each_line(*args, **options) each_line
, encoding : String encoding, flush flush, gets(limit : Int, chomp = false) : String?
gets(delimiter : Char, limit : Int, chomp = false) : String?
gets(delimiter : Char, chomp = false) : String?
gets(delimiter : String, chomp = false) : String?
gets(chomp = true) : String? gets
, gets_to_end : String gets_to_end, peek : Bytes? peek, pos pos, pos=(value) pos=, print(obj : _) : Nil
print(*objects : _) : Nil print
, printf(format_string, args : Array | Tuple) : Nil
printf(format_string, *args) : Nil printf
, puts(string : String) : Nil
puts(obj : _) : Nil
puts : Nil
puts(*objects : _) : Nil puts
, read(slice : Bytes) read, read_at(offset, bytesize, & : IO -> ) read_at, read_byte : UInt8? read_byte, read_bytes(type, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) read_bytes, read_char : Char? read_char, read_fully(slice : Bytes) : Int32 read_fully, read_fully?(slice : Bytes) : Int32? read_fully?, read_line(*args, **options) : String read_line, read_string(bytesize : Int) : String read_string, read_utf8(slice : Bytes) read_utf8, read_utf8_byte : UInt8? read_utf8_byte, rewind rewind, seek(offset, whence : Seek = Seek::Set) seek, set_encoding(encoding : String, invalid : Symbol? = nil) : Nil set_encoding, skip(bytes_count : Int) : Nil skip, skip_to_end : Nil skip_to_end, tell tell, tty? : Bool tty?, write(slice : Bytes) : Nil write, write_byte(byte : UInt8) : Nil write_byte, write_bytes(object, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) : Nil write_bytes, write_string(slice : Bytes) : Nil write_string, write_utf8(slice : Bytes) : Nil write_utf8

Class methods inherited from class IO

copy(src, dst, limit : Int) : Int64
copy(src, dst) : Int64 copy
, pipe(read_blocking = false, write_blocking = false) : Tuple(IO::FileDescriptor, IO::FileDescriptor)
pipe(read_blocking = false, write_blocking = false, &) pipe
, same_content?(stream1 : IO, stream2 : IO) : Bool same_content?

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==
, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference) : Bool
same?(other : Nil) same?
, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

Instance methods inherited from class Object

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===
, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash
, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?
, inspect(io : IO) : Nil
inspect : String inspect
, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json
, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json
, to_s(io : IO) : Nil
to_s : String to_s
, to_yaml(io : IO) : Nil
to_yaml : String to_yaml
, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
from_json(string_or_io) from_json
, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

def self.new(host : String, port : Int, backlog : Int = SOMAXCONN, dns_timeout = nil, reuse_port : Bool = false)Source

Binds a socket to the host and port combination.

def self.new(family : Family = Family::INET)Source

Creates a new TCPServer, waiting to be bound.

def self.new(port : Int, backlog = SOMAXCONN, reuse_port = false)Source

Creates a new TCP server, listening on all local interfaces (::).

def self.new(*, fd : Handle, family : Family = Family::INET)Source

Creates a TCPServer from an already configured raw file descriptor

Class Method Detail

def self.open(port : Int, backlog = SOMAXCONN, reuse_port = false, &)Source

Creates a new TCP server, listening on all interfaces, and yields it to the block. Eventually closes the server socket when the block returns.

Returns the value of the block.

def self.open(host, port, backlog = SOMAXCONN, reuse_port = false, &)Source

Creates a new TCP server and yields it to the block. Eventually closes the server socket when the block returns.

Returns the value of the block.

Instance Method Detail

def accept? : TCPSocket?Source

Accepts an incoming connection.

Returns the client TCPSocket or nil if the server is closed after invoking this method.

require "socket"

server = TCPServer.new(2022)
loop do
  if socket = server.accept?
    # handle the client in a fiber
    spawn handle_connection(socket)
  else
    # another fiber closed the server
    break
  end
end

© 2012–2021 Manas Technology Solutions.
Licensed under the Apache License, Version 2.0.
https://crystal-lang.org/api/1.2.1/TCPServer.html