What does swoole use to save fd?

from_id is which reactor thread it comes from

fd is the file descriptor of the tcp connection, which is the unique identifier of the client in swoole_server Recommended learning: swoole video tutorial)

fd is reused. When the connection is closed, fd will be reused by the new incoming connection.

The TCP connection fd being maintained Will not be reused

Calling the swoole_server->send/swoole_server->close function requires passing in the $fd parameter to be processed correctly.

If you need to send broadcasts in your business, you need to use apc/redis/memcache/swoole_table to save the value of fd.

1.6.0 and above no longer require the from_id parameter. Swoole itself provides ConnectionList to query all current fds and corresponding from_id

1.7.10 and above, fd is no longer required is the file descriptor. fd is an auto-increasing number, ranging from 1 to 16 million

If fd exceeds 16 million, it will automatically start multiplexing from 1

function my_onReceive($serv, $fd, $from_id, $data)  {
    //向Connection发送数据
    $serv->send($fd, 'Swoole: '.$data); 
    //关闭Connection
    $serv->close($fd); 
}

$fd Why use integer

$fd Use integer instead of object. The main reason is that swoole is a multi-process model. You may need to access a client connection at any time in the Worker process/Task process. If you use Object, then you need to Serialize/Unserialize. Adds additional performance overhead. If $fd is an integer, it can be used for direct storage and transfer.

In the PHP layer, client connections can also be encapsulated into objects. The advantage of object-oriented is that it is more readable and the operation of connection can be encapsulated into methods. Such as

$connection->send($data);
$connection->close();

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