UDPTransport.php

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<?php
namespace Wikimedia;
 
use InvalidArgumentException;
 
class UDPTransport {
    // Limit to 64 KiB
    public const MAX_PAYLOAD_SIZE = 65507;
    private string $host;
    private int $port;
    private $prefix;
    private int $domain;
 
    public function __construct( $host, $port, $domain, $prefix = false ) {
        $this->host = $host;
        $this->port = $port;
        $this->domain = $domain;
        $this->prefix = $prefix;
    }
 
    public static function newFromString( $info ) {
        if ( preg_match( '!^udp:(?://)?\[([0-9a-fA-F:]+)\]:(\d+)(?:/(.*))?$!', $info, $m ) ) {
            // IPv6 bracketed host
            $host = $m[1];
            $port = intval( $m[2] );
            $prefix = $m[3] ?? false;
            $domain = AF_INET6;
        } elseif ( preg_match( '!^udp:(?://)?([a-zA-Z0-9.-]+):(\d+)(?:/(.*))?$!', $info, $m ) ) {
            $host = $m[1];
            if ( !IPUtils::isIPv4( $host ) ) {
                $host = gethostbyname( $host );
            }
            $port = intval( $m[2] );
            $prefix = $m[3] ?? false;
            $domain = AF_INET;
        } else {
            throw new InvalidArgumentException( __METHOD__ . ': Invalid UDP specification' );
        }
 
        return new self( $host, $port, $domain, $prefix );
    }
 
    public function emit( $text ): void {
        // Clean it up for the multiplexer
        if ( $this->prefix !== false ) {
            $text = preg_replace( '/^/m', $this->prefix . ' ', $text );
 
            if ( strlen( $text ) > self::MAX_PAYLOAD_SIZE - 1 ) {
                $text = substr( $text, 0, self::MAX_PAYLOAD_SIZE - 1 );
            }
 
            if ( !str_ends_with( $text, "\n" ) ) {
                $text .= "\n";
            }
        } elseif ( strlen( $text ) > self::MAX_PAYLOAD_SIZE ) {
            $text = substr( $text, 0, self::MAX_PAYLOAD_SIZE );
        }
 
        $sock = socket_create( $this->domain, SOCK_DGRAM, SOL_UDP );
        if ( !$sock ) { // @todo should this throw an exception?
            return;
        }
 
        socket_sendto( $sock, $text, strlen( $text ), 0, $this->host, $this->port );
        socket_close( $sock );
    }
}
 
class_alias( UDPTransport::class, 'UDPTransport' );