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uv

Inherits from core.Object

uv.Handle

Inherits from Emitter

This class is never used directly, but is the inheritance chain of all libuv objects.

Handle:addHandlerType(name)

This is used by Emitters to register with native events when the first listener is added.

uv.Pipe

Inherits from uv.Stream

Pipe:initialize(ipc)

uv.Process

Inherits from uv.Handle

Process:initialize(command, args, options)

uv.Stream

Inherits from uv.Handle

This is never used directly. If you want to create a pure Lua stream, subclass or instantiate core.iStream.

uv.Tcp

Inherits from uv.Stream

Tcp:initialize()

uv.Timer

Inherits from uv.Handle

Timer:initialize()

uv.Tty

Inherits from uv.Stream

Tty:initialize(fd, readable)

uv.Udp

Inherits from uv.Handle

Udp:initialize()

uv.Watcher

Inherits from uv.Handle

Watcher:initialize(path)

istening'` event has been emitted.

Server:close()

Stops the server from accepting new connections. This function is asynchronous, the server is finally closed when the server emits a 'close' event.

Server:listen(port, host, listeningListener)

Begin accepting connections on the specified port and host. If the host is omitted, the server will accept connections directed to any IPv4 address (INADDR_ANY). A port value of zero will assign a random port.

This function is asynchronous. When the server has been bound, 'listening' event will be emitted. the last parameter listeningListener will be added as an listener for the 'listening' event.

One issue some users run into is getting EADDRINUSE errors. This means that another server is already running on the requested port. One way of handling this would be to wait a second and then try again. This can be done with

server:on('error', function (e)
  if e.code == 'EADDRINUSE' then
    print('Address in use, retrying...')
    timer.setTimeout(1000, function ()
      server:close()
      server:listen(PORT, HOST)
    end)
  end
end)

(Note: All sockets in Luvit set SO_REUSEADDR already)

If a path is given instead of a port, then start a UNIX socket server listening for connections on the given path.

This function is asynchronous. When the server has been bound, 'listening' event will be emitted. the last parameter listeningListener will be added as an listener for the 'listening' event.

Server:pause(msecs)

Stop accepting connections for the given number of milliseconds (default is one second). This could be useful for throttling new connections against DoS attacks or other oversubscription.

net2.Socket

Inherits from uv.Stream

This object is an abstraction of a TCP or UNIX socket. net.Socket instances implement a duplex Stream interface. They can be created by the user and used as a client (with connect()) or they can be created by Luvit and passed to the user through the 'connection' event of a server.

Socket:address()

Returns the bound address and port of the socket as reported by the operating system. Returns a table with two properties, e.g. {address = "192.168.57.1", port = 62053}

Socket:connect(port, host, connectListener)

Opens the connection for a given socket. If port and host are given, then the socket will be opened as a TCP socket, if host is omitted, localhost will be assumed. If a path is given, the socket will be opened as a unix socket to that path.

Normally this method is not needed, as net.createConnection opens the socket. Use this only if you are implementing a custom Socket or if a Socket is closed and you want to reuse it to connect to another server.

This function is asynchronous. When the 'connect' event is emitted the socket is established. If there is a problem connecting, the 'connect' event will not be emitted, the 'error' event will be emitted with the exception.

The connectListener parameter will be added as an listener for the 'connect' event.

Socket:destroy()

Ensures that no more I/O activity happens on this socket. Only necessary in case of errors (parse error or so).

Socket:finish(data, callback)

Half-closes the socket. i.e., it sends a FIN packet. It is possible the server will still send some data.

If data is specified, it is equivalent to calling socket:write(data) followed by socket:finish().

Socket:initialize(options)

Construct a new socket object.

options is an object with the following defaults:

{
  fd = nil,
  type = nil,
  allowHalfOpen = false
}

fd allows you to specify the existing file descriptor of socket. type specified underlying protocol. It can be 'tcp4', 'tcp6', or 'unix'. About allowHalfOpen, refer to createServer() and 'end' event.

Socket:pause()

Pauses the reading of data. That is, 'data' events will not be emitted. Useful to throttle back an upload.

Socket:remoteAddress()

The string representation of the remote IP address. For example, '74.125.127.100' or '2001:4860:a005::68'.

Socket:remotePort()

The numeric representation of the remote port. For example, 80 or 21.

Socket:resume()

Resumes reading after a call to pause().

Socket:setKeepAlive(enable, initialDelay)

Enable/disable keep-alive functionality, and optionally set the initial delay before the first keepalive probe is sent on an idle socket. enable defaults to false.

Set initialDelay (in milliseconds) to set the delay between the last data packet received and the first keepalive probe. Setting 0 for initialDelay will leave the value unchanged from the default (or previous) setting. Defaults to 0.

Socket:setNoDelay(noDelay)

Disables the Nagle algorithm. By default TCP connections use the Nagle algorithm, they buffer data before sending it off. Setting true for noDelay will immediately fire off data each time socket.write() is called. noDelay defaults to true.

Socket:setTimeout(timeout, callback)

Sets the socket to timeout after timeout milliseconds of inactivity on the socket. By default net.Socket do not have a timeout.

When an idle timeout is triggered the socket will receive a 'timeout' event but the connection will not be severed. The user must manually end() or destroy() the socket.

If timeout is 0, then the existing idle timeout is disabled.

The optional callback parameter will be added as a one time listener for the 'timeout' event.

Socket:write(data, callback)

Sends data on the socket. The second parameter specifies the encoding in the case of a string--it defaults to UTF8 encoding.

Returns true if the entire data was flushed successfully to the kernel buffer. Returns false if all or part of the data was queued in user memory. 'drain' will be emitted when the buffer is again free.

The optional callback parameter will be executed when the data is finally written out - this may not be immediately.

net2.connect(port, host, connectListener)

Construct a new socket object and opens a socket to the given location. When the socket is established the connect event will be emitted.

The arguments for these methods change the type of connection:

  • net.connect(port, [host], [connectListener]) - Creates a TCP connection to port on host. If host is omitted, 'localhost' will be assumed.

  • net.connect(path, [connectListener]) - Creates unix socket connection to path.

The connectListener parameter will be added as an listener for the connect event.

Here is an example of a client of echo server as described previously:

local net = require 'net'
local client = net.connect(8124, function ()
  debug('on_connect')
  client:write('world!\r\n')
end)
client:on('data', function (data)
  debug('on_data', data)
  client:end()
end)
client:on('end', function ()
  debug('on_end')
end)

To connect on the socket /tmp/echo.sock the second line would just be changed to

local client = net.connect('/tmp/echo.sock', function ()

net2.createServer(options, connectionListener)

Creates a new TCP server. The connectionListener argument is automatically set as a listener for the connection event.

options is a table with the following defaults:

{ allowHalfOpen = false }

If allowHalfOpen is true, then the socket won't automatically send a FIN packet when the other end of the socket sends a FIN packet. The socket becomes non-readable, but still writable. You should call the end() method explicitly. See end event for more information.

Here is an example of a echo server which listens for connections on port 8124:

local net = require('net')
local server = net.createServer(function (c)  -- 'connection' listener
  debug('server connected')
  c:on('end', function ()
    debug('client disconnected')
  end)
  c:write('hello\r\n')
  c:pipe(c)
end)
server:listen(8124, function ()
  print('server bound')
end)

Test this by using telnet:

telnet localhost 8124

To listen on the socket /tmp/echo.sock the third line from the last would just be changed to

server:listen('/tmp/echo.sock', function (c) {

Use nc to connect to a UNIX domain socket server:

nc -U /tmp/echo.sock