问题描述
我正在使用套接字将数据发送到可能没有响应的服务器.所以我试图通过在 SO 中使用这个解决方案来定义超时.
I am using sockets to send data to a server that may not be responding. So I am trying to define a timeout by using this solution in SO.
socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array('sec' => 1, 'usec' => 0));
socket_set_option($socket, SOL_SOCKET, SO_SNDTIMEO, array('sec' => 1, 'usec' => 0));
这在建立连接并且服务器响应时间过长时起作用.但是当它不能创建连接时 socket_connect($socket, $addr, $port);
超时大约是 20 秒.
This works when the connection is made and the server takes too long to respond.But when it can't create a connection socket_connect($socket, $addr, $port);
the timeout is about 20 seconds.
为什么会发生 20 秒的超时,我如何强制连接创建也在 1 秒后超时?
Why is this 20 second timeout happening and how can I force the connection creation to timeout after 1 second too?
推荐答案
您可以通过切换到非阻塞套接字来实现此目的,循环直到获得连接或达到超时,然后再次返回阻塞状态.
You can do this by switching to a non-blocking socket, looping until either a connection is gained or a timeout was reached, then back to blocking again.
// an unreachable address
$host = '10.0.0.1';
$port = 50000;
$timeout = 2;
$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
// switch to non-blocking
socket_set_nonblock($sock);
// store the current time
$time = time();
// loop until a connection is gained or timeout reached
while (!@socket_connect($sock, $host, $port)) {
$err = socket_last_error($sock);
// success!
if($err === 56) {
print('connected ok');
break;
}
// if timeout reaches then call exit();
if ((time() - $time) >= $timeout) {
socket_close($sock);
print('timeout reached!');
exit();
}
// sleep for a bit
usleep(250000);
}
// re-block the socket if needed
socket_set_block($sock);
如果您使用的是通过 fsockopen() 或 stream_socket_client() 创建的套接字,请参阅 @letiagoalves 答案以获得更简洁的解决方案
edit: see @letiagoalves answer for an neater solution if you are using sockets created with fsockopen() or stream_socket_client()
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