php的libev扩展

ev is a PECL extension providing inteface to libev library – high performance full-featured event loop written in C.

ABOUT LIBEV

Libev is an event loop: you register interest in certain events (such as a file descriptor being readable or a timeout occurring), and it will manage these event sources and provide your program with events.

那么什么是libev呢，从网上摘录一段:

libev 是高性能事件循环/事件模型的网络库，并且包含大量新特性。

它是继lievent和Event perl module之后的一套全新网络库。它追求的目标：速度更快，bug更少，特性更多，体积更小。 www.2cto.com

它和libevent很像，按照作者的介绍，可以作为libevent的替代者，能够提供更高的性能。并不需要复杂的配置。

看起来和之前提到的libevent大有渊源，但是这个扩展的作者显然比较活跃，一周内提交了3个版本。

代码示例

timer的使用

// 创建一个timer并于2秒后触发

$w1 = new EvTimer(2, 0, function () {

echo "2 seconds elapsed\n";

});

// 创建一个timer并于2秒后触发，每秒重复

// 直到我们手工停止

$w2 = new EvTimer(2, 1, function ($w) {

echo "is called every second, is launched after 2 seconds\n";

echo "iteration = ", Ev::iteration(), PHP_EOL;

// Stop the watcher after 5 iterations

Ev::iteration() == 5 and $w->stop();

// Stop the watcher if further calls cause more than 10 iterations

Ev::iteration() >= 10 and $w->stop();

});

// 创建一个已停止的timer，手工start才有效

$w_stopped = EvTimer::createStopped(10, 5, function($w) {

echo "Callback of a timer created as stopped\n";

// Stop the watcher after 2 iterations

Ev::iteration() >= 2 and $w->stop();

});

// Loop until Ev::stop() is called or all of watchers stop

Ev::run();

// Start and look if it works

$w_stopped->start();

echo "Run single iteration\n";

Ev::run(Ev::RUN_ONCE);

echo "Restart the second watcher and try to handle the same events, but don't block\n";

$w2->again();

Ev::run(Ev::RUN_NOWAIT);

$w = new EvTimer(10, 0, function() {});

echo "Running a blocking loop\n";

Ev::run();

echo "END\n";

?>

输出内容

2 seconds elapsed

is called every second, is launched after 2 seconds

iteration = 1

is called every second, is launched after 2 seconds

iteration = 2

is called every second, is launched after 2 seconds

iteration = 3

is called every second, is launched after 2 seconds

iteration = 4

is called every second, is launched after 2 seconds

iteration = 5

Run single iteration

Callback of a timer created as stopped

Restart the second watcher and try to handle the same events, but don't block

Running a blocking loop

is called every second, is launched after 2 seconds

iteration = 8

is called every second, is launched after 2 seconds

iteration = 9

is called every second, is launched after 2 seconds

iteration = 10

END

I/O事件

例1

// Wait until STDIN is readable

$w = new EvIo(STDIN, Ev::READ, function ($watcher, $revents) {

echo "STDIN is readable\n";

});

Ev::run(Ev::RUN_ONCE);

?>

例2

/* Use some async I/O to access a socket */

// `sockets' extension still logs warnings

// for EINPROGRESS, EAGAIN/EWOULDBLOCK etc.

error_reporting(E_ERROR);

$e_nonblocking = array (/*EAGAIN or EWOULDBLOCK*/11, /*EINPROGRESS*/115);

// Get the port for the WWW service

$service_port = getservbyname('www', 'tcp');

// Get the IP address for the target host

$address = gethostbyname('google.co.uk');

// Create a TCP/IP socket

$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);

if ($socket === FALSE) {

echo "socket_create() failed: reason: "

.socket_strerror(socket_last_error()) . "\n";

}

// Set O_NONBLOCK flag

socket_set_nonblock($socket);

// Abort on timeout

$timeout_watcher = new EvTimer(10.0, 0., function () use ($socket) {

socket_close($socket);

Ev::stop(Ev::BREAK_ALL);

});

// Make HEAD request when the socket is writable

$write_watcher = new EvIo($socket, Ev::WRITE, function ($w)

use ($socket, $timeout_watcher, $e_nonblocking) {

// Stop timeout watcher

$timeout_watcher->stop();

// Stop write watcher

$w->stop();

$in = "HEAD / HTTP/1.1\r\n";

$in .= "Host: google.co.uk\r\n";

$in .= "Connection: Close\r\n\r\n";

if (!socket_write($socket, $in, strlen($in))) {

trigger_error("Failed writing $in to socket", E_USER_ERROR);

}

$read_watcher = new EvIo($socket, Ev::READ, function ($w, $re)

use ($socket, $e_nonblocking) {

// Socket is readable. recv() 20 bytes using non-blocking mode

$ret = socket_recv($socket, $out, 20, MSG_DONTWAIT);

if ($ret) {

echo $out;

} elseif ($ret === 0) {

// All read

$w->stop();

socket_close($socket);

return;

}

// Caught EINPROGRESS, EAGAIN, or EWOULDBLOCK

if (in_array(socket_last_error(), $e_nonblocking)) {

return;

}

$w->stop();

socket_close($socket);

});

Ev::run();

});

$result = socket_connect($socket, $address, $service_port);

Ev::run();

?>

输出

HTTP/1.1 301 Moved Permanently

Location: http://www.google.co.uk/

Content-Type: text/html; charset=UTF-8

Date: Sun, 23 Dec 2012 16:08:27 GMT

Expires: Tue, 22 Jan 2013 16:08:27 GMT

Cache-Control: public, max-age=2592000

Server: gws

Content-Length: 221

X-XSS-Protection: 1; mode=block

X-Frame-Options: SAMEORIGIN

Connection: close