Sockets should be first shutdown and then closed.
<?php
// Sample: Closing sockets gracefully
socket_shutdown($sock, 2);
socket_close($sock);
?>
socket_shutdown
(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
socket_shutdown — 关闭套接字接收或发送，或两者都关闭
说明
socket_shutdown() 函数允许通过 socket 停止接收、发送或所有数据（默认）。
注意:
关联的一个或多个缓冲区可能会清空，也可能不会。
参数
-
socket -
从 socket_create() 创建的 Socket 实例。
-
mode -
mode的值可以是以下之一：mode可用值0关闭套接字读 1关闭套接字写 2关闭套接字读和写
返回值
成功时返回 true， 或者在失败时返回 false。
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User Contributed Notes 5 notes
ludvig dot ericson at gmail dot com ¶
19 years ago
Anonymous ¶
2 years ago
Shutting down is a formality two peers can do before closing their connections. It's not required, but it can help assert your I/O procedures, so it's useful.
If writing is shut down, trying to send will result in a pipe error, and the remote peer will read an empty string after receiving all other pending data.
If reading is shut down, trying to receive will return an empty string, and the remote peer will get a pipe error if they try to send.
Writing should be shut down first between two peers. Remaining data should then be read and handled. If anything is sent at this point it should be a "goodbye" (nothing that requires the remote peer to write back to you). Finally, reading can be shut down.
Selection on a shut down channel will always succeed. Similarly, the remote peer will always succeed at selecting the opposite channel.
richard dot thomas at psysolutions dot com ¶
19 years ago
That is not a good example of a graceful shutdown. One should close the sending side of the socket and continue to read until the remote end closes its sending connection.
renmengyang567 at gmail dot com ¶
5 years ago
<explain>
In this case, the TCP client is gracefully disconnected from the server
<?php
define('BUF_SIZE',10);
// create for tcp
$sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_bind($sock, '127.0.0.1',5200);
socket_listen($sock,1024);
$fp = fopen('./socket_shutdown.php','rb');
$clnt_sock = socket_accept($sock);
while(!feof($fp)) {
$str = fread($fp,BUF_SIZE);
socket_write($clnt_sock,$str,BUF_SIZE);
}
$eof = "\n";
socket_write($clnt_sock,$eof,strlen($eof));
//disconnect output stream(断开输入流)
socket_shutdown($clnt_sock,1);
$ret = socket_read($clnt_sock, 100);
printf("Message from client:%s\n",$ret);
socket_close($clnt_sock);
socket_close($sock);
?>
<?php
// for tcp-client
$clnt_sock = socket_create(AF_INET, SOCK_STREAM, getprotobyname('tcp'));
socket_connect($clnt_sock, '127.0.0.1', 5200);
while (($cnt= @socket_read($clnt_sock, 10,PHP_NORMAL_READ)) !==false) {
file_put_contents('./receive.data',$cnt,FILE_APPEND);
}
print "receive file data".PHP_EOL;
socket_write($clnt_sock, "Tank you");
socket_close($clnt_sock);
?>
recycling dot sp dot am at gmail dot com ¶
14 years ago
Shutdown and SOL_TCP:
<?php
$a= socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_shutdown($a, 2)
?>
PHP Warning: socket_shutdown(): unable to shutdown socket [107]: Transport endpoint is not connected
Shutdown and SOL_UDP:
<?php
$a= socket_create(AF_INET, SOCK_STREAM, SOL_UDP);
socket_shutdown($a, 2)
?>
PHP Warning: socket_shutdown(): unable to shutdown socket [107]: Transport endpoint is not connected
Conclusion: if you are not actually connected, shutdown will fails with socket_error = 107, Transport endpoint is not connected. This is true for both TPC and UDP connection (which is suprising, UDP being a connectionless protocol). This is true no matter the value set for the how parameter.
