常用的方法

判断字符串中是否包含某一个字符(php8 str_contains方法)
/**
* Determine if a given string contains a given substring.
*
* @param  string  $haystack
* @param  string|string[]  $needles
* @return bool
* 
*/
public static function contains($haystack, $needles)
    {
        foreach ((array) $needles as $needle) {
            if ($needle !== '' && mb_strpos($haystack, $needle) !== false) {
                return true;
            }
        }

        return false;
    }

Str::contains($keyword, ['_']

    /**
     * 获取客户端IP地址
     */
    static public function getClientIP() {
        static $ip = NULL;
        if ( $ip !== NULL )
            return $ip;
        if ( isset( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
            $arr = explode( ',', $_SERVER['HTTP_X_FORWARDED_FOR'] );
            $pos = array_search( 'unknown', $arr );
            if ( false !== $pos )
                unset( $arr[$pos] );
            $ip = trim( $arr[0] );
        } elseif ( isset( $_SERVER['HTTP_CLIENT_IP'] ) ) {
            $ip = $_SERVER['HTTP_CLIENT_IP'];
        } elseif ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
            $ip = $_SERVER['REMOTE_ADDR'];
        }
        // IP地址合法验证
        $ip = ( false !== ip2long( $ip ) ) ? $ip : '0.0.0.0';
        return $ip;
    }

    /**
     * 验证手机号码
     */
    public static function mobile( $str ) {
        if ( empty( $str ) ) {
            return true;
        }

        return preg_match( '#^13[\d]{9}$|14^[0-9]\d{8}|^15[0-9]\d{8}$|^18[0-9]\d{8}$#', $str );
    }

/**
     * 验证身份证(中国)
     */
    public static function idCard( $str ) {
        $str = trim( $str );
        if ( empty( $str ) )
            return true;

        if ( preg_match( "/^([0-9]{15}|[0-9]{17}[0-9a-z])$/i", $str ) )
            return true;
        else
            return false;
    }

    /**
     * 列出文件夹列表
     *
     * @param $dirname
     * @return array
     */
    public static function getDir( $dirname ) {
        $files = array();
        if ( is_dir( $dirname ) ) {
            $fileHander = opendir( $dirname );
            while ( ( $file = readdir( $fileHander ) ) !== false ) {
                $filepath = $dirname . '/' . $file;
                if ( strcmp( $file, '.' ) == 0 || strcmp( $file, '..' ) == 0 || is_file( $filepath ) ) {
                    continue;
                }
                $files[] =  self::autoCharset( $file, 'GBK', 'UTF8' );
            }
            closedir( $fileHander );
        }
        return $files;
    }

    /**
     * 获取客户端IP地址
     */
    static public function getClientIP() {
        static $ip = NULL;
        if ( $ip !== NULL )
            return $ip;
        if ( isset( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
            $arr = explode( ',', $_SERVER['HTTP_X_FORWARDED_FOR'] );
            $pos = array_search( 'unknown', $arr );
            if ( false !== $pos )
                unset( $arr[$pos] );
            $ip = trim( $arr[0] );
        } elseif ( isset( $_SERVER['HTTP_CLIENT_IP'] ) ) {
            $ip = $_SERVER['HTTP_CLIENT_IP'];
        } elseif ( isset( $_SERVER['REMOTE_ADDR'] ) ) {
            $ip = $_SERVER['REMOTE_ADDR'];
        }
        // IP地址合法验证
        $ip = ( false !== ip2long( $ip ) ) ? $ip : '0.0.0.0';
        return $ip;
    }