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. 那麼什麼是libev呢，從網上摘錄一段: libev 是高性能事件循環/事件模型的網絡庫，並且包含大量新特性。 它是繼lievent和Event perl module之後的一套全新網絡庫。它追求的目標：速度更快，bug更少，特性更多，體積更小。 www.2cto.com 它和libevent很像，按照作者的介紹，可以作為libevent的替代者，能夠提供更高的性能。並不需要復雜的配置。 看起來和之前提到的libevent大有淵源，但是這個擴展的作者顯然比較活躍，一周內提交了3個版本。 代碼示例 timer的使用 <?php // 創建一個timer並於2秒後觸發 $w1 = new EvTimer(2, 0, function () { echo "2 seconds elapsed\n"; }); // 創建一個timer並於2秒後觸發，每秒重復 // 直到我們手工停止 $w2 = new EvTimer(2, 1, function ($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(); }); // 創建一個已停止的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"; ?> 輸出內容 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 <?php // 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 <?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 $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); if ($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(); ?> 輸出 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
