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# EventListener::__construct

(PECL event >= 1.2.6-beta)

EventListener::__construct — Creates new connection listener associated with an event base

### Description

public EventListener::__construct ( EventBase `$base` , callable `$cb` , mixed `$data` , int `$flags` , int `$backlog` , mixed `$target` )

Creates new connection listener associated with an event base.

### Parameters

`base`

  Associated event base.

`cb`

  A callable that will be invoked when new connection received.

`data`

  Custom user data attached to `cb` .

`flags`

  Bit mask of EventListener::OPT_* constants. See EventListener constants .

`backlog`

  Controls the maximum number of pending connections that the network stack should allow to wait in a not-yet-accepted state at any time; see documentation for your system’s listen function for more details. If `backlog` is negative, Libevent tries to pick a good value for the `backlog` ; if it is zero, Event assumes that listen is already called on the socket( `target` )

`target`

  May be string, socket resource, or a stream associated with a socket. In case if `target` is a string, the string will be parsed as network address. It will be interpreted as a UNIX domain socket path, if prefixed with 'unix:' , e.g. 'unix:/tmp/my.sock' .

### Return Values

Returns EventListener object representing the event connection listener.

### Changelog

Version | Description
--- | ---
1.5.0 | UNIX domain sockets' support added.

### Examples

Example #1 EventListener::__construct() example

`<?php
/*
* Simple echo server based on libevent's connection listener.
*
* Usage:
* 1) In one terminal window run:
*
* $ php listener.php 9881
*
* 2) In another terminal window open up connection, e.g.:
*
* $ nc 127.0.0.1 9881
*
* 3) start typing. The server should repeat the input.
*/
class MyListenerConnection {
private $bev, $base;
public function __destruct() {
$this->bev->free();
}
public function __construct($base, $fd) {
$this->base = $base;
$this->bev = new EventBufferEvent($base, $fd, EventBufferEvent::OPT_CLOSE_ON_FREE);
$this->bev->setCallbacks(array($this, "echoReadCallback"), NULL,
array($this, "echoEventCallback"), NULL);
if (!$this->bev->enable(Event::READ)) {
echo "Failed to enable READ\n";
return;
}
}
public function echoReadCallback($bev, $ctx) {
// Copy all the data from the input buffer to the output buffer
// Variant #1
$bev->output->addBuffer($bev->input);
/* Variant #2 */
/*
$input = $bev->getInput();
$output = $bev->getOutput();
$output->addBuffer($input);
*/
}
public function echoEventCallback($bev, $events, $ctx) {
if ($events & EventBufferEvent::ERROR) {
echo "Error from bufferevent\n";
}
if ($events & (EventBufferEvent::EOF | EventBufferEvent::ERROR)) {
//$bev->free();
$this->__destruct();
}
}
}
class MyListener {
public $base,
$listener,
$socket;
private $conn = array();
public function __destruct() {
foreach ($this->conn as &$c) $c = NULL;
}
public function __construct($port) {
$this->base = new EventBase();
if (!$this->base) {
echo "Couldn't open event base";
exit(1);
}
// Variant #1
/*
$this->socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if (!socket_bind($this->socket, '0.0.0.0', $port)) {
echo "Unable to bind socket\n";
exit(1);
}
$this->listener = new EventListener($this->base,
array($this, "acceptConnCallback"), $this->base,
EventListener::OPT_CLOSE_ON_FREE | EventListener::OPT_REUSEABLE,
-1, $this->socket);
*/
// Variant #2
$this->listener = new EventListener($this->base,
array($this, "acceptConnCallback"), $this->base,
EventListener::OPT_CLOSE_ON_FREE | EventListener::OPT_REUSEABLE, -1,
"0.0.0.0:$port");
if (!$this->listener) {
echo "Couldn't create listener";
exit(1);
}
$this->listener->setErrorCallback(array($this, "accept_error_cb"));
}
public function dispatch() {
$this->base->dispatch();
}
// This callback is invoked when there is data to read on $bev
public function acceptConnCallback($listener, $fd, $address, $ctx) {
// We got a new connection! Set up a bufferevent for it. */
$base = $this->base;
$this->conn[] = new MyListenerConnection($base, $fd);
}
public function accept_error_cb($listener, $ctx) {
$base = $this->base;
fprintf(STDERR, "Got an error %d (%s) on the listener. "
."Shutting down.\n",
EventUtil::getLastSocketErrno(),
EventUtil::getLastSocketError());
$base->exit(NULL);
}
}
$port = 9808;
if ($argc > 1) {
$port = (int) $argv[1];
}
if ($port <= 0 || $port > 65535) {
exit("Invalid port");
}
$l = new MyListener($port);
$l->dispatch();
?>`

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PHP Manual