Question

我的目标：在php中发送UDP广播消息。消息必须是字节字符串。

这是我的测试代码

const TIMEOUT = 5;
const PORT = 8888;
const IP = "255.255.255.255";
const STR = "test";

$sock = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP); 
socket_set_option($sock, SOL_SOCKET, SO_BROADCAST, 1);
socket_set_option($sock,SOL_SOCKET,SO_RCVTIMEO,array("sec"=>TIMEOUT,"usec"=>0));
socket_sendto($sock, STR, strlen(STR), 0, IP, PORT);

//wait the responses for TIMEOUT sec
while(true) {
    $ret = @socket_recvfrom($sock, $buf, 20, 0, $ipDevice, $portDevice);
    if($ret === false) break;
        echo "-".$buf." - ".$ipDevice.":".$portDevice . "<br>";
}
socket_close($sock);

但是 socket_sendto 需要发送一个字符串参数（我的STR变量）。

所以问题是：如何将字符串（我的STR变量）转换为字节字符串？

Answer 1

以下是如何进行UDP广播的方法：

<?php
$broadcast_string = "test";
$port = 1234;
$sock = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_set_option($sock, SOL_SOCKET, SO_BROADCAST, 1);
socket_sendto($sock, $broadcast_string, strlen($broadcast_string), 0, '255.255.255.255', $port);
socket_close($sock);
?>

修改以下是将string转换为字节串的方法：

$byte_array = unpack('C*', 'The quick fox jumped over the lazy brown dog'); var_dump($byte_array); // $byte_array should be int[] which can be converted // to byte[] since values are range of 0 - 255

Php：通过UDP发送字节串

1 个答案: