本文大约总结了php编程中的五种并发方式：
1.curl_multi_init
文档中说的是 allows the processing of multiple curl handles asynchronously. 确实是异步。这里需要理解的是select这个方法，文档中是这么解释的blocks until there is activity on any of the curl_multi connections.。了解一下常见的异步模型就应该能理解，select, epoll，都很有名
<?php
// build the individual requests as above, but do not execute them
$ch_1 = curl_init('http://www.jb51.net/');
$ch_2 = curl_init('http://www.jb51.net/');
curl_setopt($ch_1, curlopt_returntransfer, true);
curl_setopt($ch_2, curlopt_returntransfer, true);
// build the multi-curl handle, adding both $ch
$mh = curl_multi_init();
curl_multi_add_handle($mh, $ch_1);
curl_multi_add_handle($mh, $ch_2);
// execute all queries simultaneously, and continue when all are complete
$running = null;
do {
curl_multi_exec($mh, $running);
$ch = curl_multi_select($mh);
if($ch !== 0){
$info = curl_multi_info_read($mh);
if($info){
var_dump($info);
$response_1 = curl_multi_getcontent($info['handle']);
echo "$response_1 n";
break;
}
}
} while ($running > 0);
//close the handles
curl_multi_remove_handle($mh, $ch_1);
curl_multi_remove_handle($mh, $ch_2);
curl_multi_close($mh);
这里我设置的是，select得到结果，就退出循环，并且删除 curl resource, 从而达到取消http请求的目的。
2.swoole_client
swoole_client提供了异步模式，我竟然把这个忘了。这里的sleep方法需要swoole版本大于等于1.7.21, 我还没升到这个版本，所以直接exit也可以。
<?php
$client = new swoole_client(swoole_sock_tcp, swoole_sock_async);
//设置事件回调函数
$client->on("connect", function($cli) {
$req = "get / http/1.1rn
host: www.jb51.netrn
connection: keep-alivern
cache-control: no-cachern
pragma: no-cachernrn";
for ($i=0; $i < 3; $i++) {
$cli->send($req);
}
});
$client->on("receive", function($cli, $data){
echo "received: ".$data."n";
exit(0);
$cli->sleep(); // swoole >= 1.7.21
});
$client->on("error", function($cli){
echo "connect failedn";
});
$client->on("close", function($cli){
echo "connection closen";
});
//发起网络连接
$client->connect('183.207.95.145', 80, 1);
3.process
哎，竟然差点忘了 swoole_process, 这里就不用 pcntl 模块了。但是写完发现，这其实也不算是中断请求，而是哪个先到读哪个，忽视后面的返回值。
<?php
$workers = [];
$worker_num = 3;//创建的进程数
$finished = false;
$lock = new swoole_lock(swoole_mutex);
for($i=0;$i<$worker_num ; $i++){
$process = new swoole_process('process');
//$process->usequeue();
$pid = $process->start();
$workers[$pid] = $process;
}
foreach($workers as $pid => $process){
//子进程也会包含此事件
swoole_event_add($process->pipe, function ($pipe) use($process, $lock, &$finished) {
$lock->lock();
if(!$finished){
$finished = true;
$data = $process->read();
echo "recv: " . $data.php_eol;
}
$lock->unlock();
});
}
function process(swoole_process $process){
$response = 'http response';
$process->write($response);
echo $process->pid,"t",$process->callback .php_eol;
}
for($i = 0; $i < $worker_num; $i++) {
$ret = swoole_process::wait();
$pid = $ret['pid'];
echo "worker exit, pid=".$pid.php_eol;
}
4.pthreads
编译pthreads模块时，提示php编译时必须打开zts, 所以貌似必须 thread safe 版本才能使用. wamp中多php正好是ts的，直接下了个dll, 文档中的说明复制到对应目录，就在win下测试了。 还没完全理解，查到文章说 php 的 pthreads 和 posix pthreads是完全不一样的。代码有些烂，还需要多看看文档，体会一下。
<?php
class foo extends stackable {
public $url;
public $response = null;
public function __construct(){
$this->url = 'http://www.jb51.net';
}
public function run(){}
}
class process extends worker {
private $text = "";
public function __construct($text,$object){
$this->text = $text;
$this->object = $object;
}
public function run(){
while (is_null($this->object->response)){
print " thread {$this->text} is runningn";
$this->object->response = 'http response';
sleep(1);
}
}
}
$foo = new foo();
$a = new process("a",$foo);
$a->start();
$b = new process("b",$foo);
$b->start();
echo $foo->response;
5.yield
以同步方式书写异步代码：
<?php
class asyncserver {
protected $handler;
protected $socket;
protected $tasks = [];
protected $timers = [];
public function __construct(callable $handler) {
$this->handler = $handler;
$this->socket = socket_create(af_inet, sock_dgram, sol_udp);
if(!$this->socket) {
die(socket_strerror(socket_last_error())."n");
}
if (!socket_set_nonblock($this->socket)) {
die(socket_strerror(socket_last_error())."n");
}
if(!socket_bind($this->socket, "0.0.0.0", 1234)) {
die(socket_strerror(socket_last_error())."n");
}
}
public function run() {
while (true) {
$now = microtime(true) * 1000;
foreach ($this->timers as $time => $sockets) {
if ($time > $now) break;
foreach ($sockets as $one) {
list($socket, $coroutine) = $this->tasks[$one];
unset($this->tasks[$one]);
socket_close($socket);
$coroutine->throw(new exception("timeout"));
}
unset($this->timers[$time]);
}
$reads = array($this->socket);
foreach ($this->tasks as list($socket)) {
$reads[] = $socket;
}
$writes = null;
$excepts= null;
if (!socket_select($reads, $writes, $excepts, 0, 1000)) {
continue;
}
foreach ($reads as $one) {
$len = socket_recvfrom($one, $data, 65535, 0, $ip, $port);
if (!$len) {
//echo "socket_recvfrom fail.n";
continue;
}
if ($one == $this->socket) {
//echo "[run]request recvfrom succ. data=$data ip=$ip port=$portn";
$handler = $this->handler;
$coroutine = $handler($one, $data, $len, $ip, $port);
if (!$coroutine) {
//echo "[run]everything is done.n";
continue;
}
$task = $coroutine->current();
//echo "[run]asynctask recv. data=$task->data ip=$task->ip port=$task->port timeout=$task->timeoutn";
$socket = socket_create(af_inet, sock_dgram, sol_udp);
if(!$socket) {
//echo socket_strerror(socket_last_error())."n";
$coroutine->throw(new exception(socket_strerror(socket_last_error()), socket_last_error()));
continue;
}
if (!socket_set_nonblock($socket)) {
//echo socket_strerror(socket_last_error())."n";
$coroutine->throw(new exception(socket_strerror(socket_last_error()), socket_last_error()));
continue;
}
socket_sendto($socket, $task->data, $task->len, 0, $task->ip, $task->port);
$deadline = $now + $task->timeout;
$this->tasks[$socket] = [$socket, $coroutine, $deadline];
$this->timers[$deadline][$socket] = $socket;
} else {
//echo "[run]response recvfrom succ. data=$data ip=$ip port=$portn";
list($socket, $coroutine, $deadline) = $this->tasks[$one];
unset($this->tasks[$one]);
unset($this->timers[$deadline][$one]);
socket_close($socket);
$coroutine->send(array($data, $len));
}
}
}
}
}
class asynctask {
public $data;
public $len;
public $ip;
public $port;
public $timeout;
public function __construct($data, $len, $ip, $port, $timeout) {
$this->data = $data;
$this->len = $len;
$this->ip = $ip;
$this->port = $port;
$this->timeout = $timeout;
}
}
function asyncsendrecv($req_buf, $req_len, $ip, $port, $timeout) {
return new asynctask($req_buf, $req_len, $ip, $port, $timeout);
}
function requesthandler($socket, $req_buf, $req_len, $ip, $port) {
//echo "[requesthandler] before yield asynctask. req=$req_bufn";
try {
list($rsp_buf, $rsp_len) = (yield asyncsendrecv($req_buf, $req_len, "127.0.0.1", 2345, 3000));
} catch (exception $ex) {
$rsp_buf = $ex->getmessage();
$rsp_len = strlen($rsp_buf);
//echo "[exception]$rsp_bufn";
}
//echo "[requesthandler] after yield asynctask. rsp=$rsp_bufn";
socket_sendto($socket, $rsp_buf, $rsp_len, 0, $ip, $port);
}
$server = new asyncserver(requesthandler);
$server->run();
?>
代码解读：
借助php内置array能力，实现简单的“超时管理”，以毫秒为精度作为时间分片；
封装asyncsendrecv接口，调用形如yield asyncsendrecv()，更加自然；
添加exception作为错误处理机制，添加ret_code亦可，仅为展示之用。
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