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Esempi

Example #1 Simple timers

<?php
// Create and start timer firing after 2 seconds
$w1 = new EvTimer(20, function () {
    echo 
"2 seconds elapsed\n";
});

// Create and launch timer firing after 2 seconds repeating each second
// until we manually stop it
$w2 = new EvTimer(21, function ($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() == and $w->stop();
    
// Stop the watcher if further calls cause more than 10 iterations
    
Ev::iteration() >= 10 and $w->stop();
});

// Create stopped timer. It will be inactive until we start it ourselves
$w_stopped EvTimer::createStopped(105, function($w) {
    echo 
"Callback of a timer created as stopped\n";

    
// Stop the watcher after 2 iterations
    
Ev::iteration() >= 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(100, function() {});
echo 
"Running a blocking loop\n";
Ev::run();
echo 
"END\n";
?>

Il precedente esempio visualizzerĂ  qualcosa simile a:

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

Example #2 Periodic timer. Tick each 10.5 seconds

<?php
$w 
= new EvPeriodic(0.10.5NULL, function ($w$revents) {
    echo 
time(), PHP_EOL;
});

Ev::run();
?>

Example #3 Periodic timer. Use reschedule callback

<?php
// Tick each 10.5 seconds

function reschedule_cb ($watcher$now) {
    return 
$now + (10.5. - fmod($now10.5));
}

$w = new EvPeriodic(0.0."reschedule_cb", function ($w$revents) {
    echo 
time(), PHP_EOL;
});

Ev::run();
?>

Example #4 Periodic timer. Tick every 10.5 seconds starting at now

<?php
// Tick every 10.5 seconds starting at now
$w = new EvPeriodic(fmod(Ev::now(), 10.5), 10.5NULL, function ($w$revents) {
    echo 
time(), PHP_EOL;
});

Ev::run();
?>

Example #5 Wait until STDIN is readable

<?php
// Wait until STDIN is readable
$w = new EvIo(STDINEv::READ, function ($watcher$revents) {
    echo 
"STDIN is readable\n";
});

Ev::run(Ev::RUN_ONCE);
?>

Example #6 Use some async I/O to access a socket

<?php
/* 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_INETSOCK_STREAMSOL_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
$timeout_watcher = new EvTimer(10.00., function () use ($socket) {
    
socket_close($socket);
    
Ev::stop(Ev::BREAK_ALL);
});

// Make HEAD request when the socket is writable
$write_watcher = new EvIo($socketEv::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($socket$instrlen($in))) {
        
trigger_error("Failed writing $in to socket"E_USER_ERROR);
    }

    
$read_watcher = new EvIo($socketEv::READ, function ($w$re)
        use (
$socket$e_nonblocking)
    {
        
// Socket is readable. recv() 20 bytes using non-blocking mode
        
$ret socket_recv($socket$out20MSG_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();
?>

Il precedente esempio visualizzerĂ  qualcosa simile a:

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


Example #7 Embedding one loop into another

<?php
/*
* Try to get an embeddable event loop and embed it into the default event loop.
* If it is impossible, use the default
* loop. The default loop is stored in $loop_hi, while the embeddable loop is
* stored in $loop_lo(which is $loop_hi in the case no embeddable loop can be
* used).
*
* Sample translated to PHP
* http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#Examples_CONTENT-9
*/
$loop_hi EvLoop::defaultLoop();
$loop_lo NULL;
$embed   NULL;

/*
* See if there is a chance of getting one that works
* (flags' value of 0 means autodetection)
*/
$loop_lo Ev::embeddableBackends() & Ev::recommendedBackends()
    ? new 
EvLoop(Ev::embeddableBackends() & Ev::recommendedBackends())
    : 
0;

if (
$loop_lo) {
    
$embed = new EvEmbed($loop_lo, function () {});
} else {
    
$loop_lo $loop_hi;
}
?>

Example #8 Embedding loop created with kqueue backend into the default loop

<?php
/*
* Check if kqueue is available but not recommended and create a kqueue backend
* for use with sockets (which usually work with any kqueue implementation).
* Store the kqueue/socket-only event loop in loop_socket. (One might optionally
* use EVFLAG_NOENV, too)
*
* Example borrowed from
* http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#Examples_CONTENT-9
*/
$loop        EvLoop::defaultLoop();
$socket_loop NULL;
$embed       NULL;

if (
Ev::supportedBackends() & ~Ev::recommendedBackends() & Ev::BACKEND_KQUEUE) {
    if ((
$socket_loop = new EvLoop(Ev::BACKEND_KQUEUE))) {
        
$embed = new EvEmbed($loop);
    }
}

if (!
$socket_loop) {
    
$socket_loop $loop;
}

// Now use $socket_loop for all sockets, and $loop for anything else
?>

Example #9 Handle SIGTERM signal

<?php
$w 
= new EvSignal(SIGTERM, function ($watcher) {
    echo 
"SIGTERM received\n";
    
$watcher->stop();
});

Ev::run();
?>

Example #10 Monitor changes of /var/log/messages

<?php
// Use 10 second update interval.
$w = new EvStat("/var/log/messages"8, function ($w) {
    echo 
"/var/log/messages changed\n";

    
$attr $w->attr();

    if (
$attr['nlink']) {
        
printf("Current size: %ld\n"$attr['size']);
        
printf("Current atime: %ld\n"$attr['atime']);
        
printf("Current mtime: %ld\n"$attr['mtime']);
    } else {
        
fprintf(STDERR"`messages` file is not there!");
        
$w->stop();
    }
});

Ev::run();
?>

Example #11 Monotor changes of /var/log/messages. Avoid missing updates by means of one second delay

<?php
$timer 
EvTimer::createStopped(0.1.02, function ($w) {
    
$w->stop();

    
$stat $w->data;

    
// 1 second after the most recent change of the file
    
printf("Current size: %ld\n"$stat->attr()['size']);
});

$stat = new EvStat("/var/log/messages"0., function () use ($timer) {
    
// Reset timer watcher
    
$timer->again();
});

$timer->data $stat;

Ev::run();
?>

Example #12 Process status changes

<?php
$pid 
pcntl_fork();

if (
$pid == -1) {
    
fprintf(STDERR"pcntl_fork failed\n");
} elseif (
$pid) {
    
$w = new EvChild($pidFALSE, function ($w$revents) {
        
$w->stop();

        
printf("Process %d exited with status %d\n"$w->rpid$w->rstatus);
    });

    
Ev::run();

    
// Protect against Zombies
    
pcntl_wait($status);
} else {
    
//Forked child
    
exit(2);
}
?>
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