php-fpm.log 和 slow.log 这两个日志文件都比较重要，它们是在目录 /usr/local/php/var/log，我发现 php-fpm.log 已经很大了，打开可以翻很多很多页，最早还是14年的记录了。它们可以清空，但不要删除。清空方法很简单，退到/usr/local/php/var/log后，执行：
cat /dev/null > php-fpm.log
cat /dev/null > slow.log

　　同样的方法，可以清空 Linux 系统日志。一般系统日志在/var/log/ 下，可以ls -lh /var/log/ 看一下占用的大小。
cat /dev/null > /var/log/syslog
cat /dev/null > /var/adm/sylog
cat /dev/null > /var/log/wtmp
cat /dev/null > /var/log/maillog
cat /dev/null > /var/log/messages
cat /dev/null > /var/log/maillog
cat /dev/null > /var/log/mail.info

原文：https://ihacksoft.com/1315.html

/**
    * 将字符串转换成二进制
    * @param type $str
    * @return type
    */
    function StrToBin($str){
        //1.列出每个字符
        $arr = preg_split('/(?<!^)(?!$)/u', $str);
        //2.unpack字符
        foreach($arr as &$v){
            $temp = unpack('H*', $v);
            $v = base_convert($temp[1], 16, 2);
            unset($temp);
        }

        return join(' ',$arr);
    }

    /**
    * 将二进制转换成字符串
    * @param type $str
    * @return type
    */
    function BinToStr($str){
        $arr = explode(' ', $str);
        foreach($arr as &$v){
            $v = pack("H".strlen(base_convert($v, 2, 16)), base_convert($v, 2, 16));
        }
        return join('', $arr);
    }

原文：https://www.cnblogs.com/chenggege/p/7761287.html

在头部加上

  header("Content-type: application/xml");

范例：

$res = $this->arrayToXml($data,$amount['count'],$page_count,$page);
header("Content-type: text/xml");
echo $res;

//数组转XML
    public function arrayToXml($data,$amount,$page_count,$page)
    {
//    	var_dump($data);die;
        $xml = "<response><code>0</code><msg>成功</msg><total_results>{$amount}</total_results><total_page>{$page_count}</total_page><current_page>{$page}</current_page><order_list>";
 
        foreach ($data as $key=>$val)
        {
            $xml.= "<order><modified></modified><receiver_zip>-</receiver_zip><is_tax>false</is_tax><invoice_type></invoice_type><invoice_title></invoice_title><buyer_cod_fee>0.0</buyer_cod_fee><point_fee></point_fee><coupon_pay></coupon_pay><payments></payments>";
            foreach($val['order'] as $k=>$v){
                if (is_numeric($v)){
                    $xml.="<".$k.">".$v."</".$k.">";
                }else{
                    $xml.="<".$k.">".$v."</".$k.">";
                }
            }
            $xml.= "<itemlist>";
            foreach($val['itemlist'] as $key=>$vv){
                $xml.= "<item>";
                foreach($vv as $kk=>$vs){
                    $xml.="<".$kk.">".$vs."</".$kk.">";
                }
                $xml.= "<shop_sku_id></shop_sku_id><sku_name></sku_name><oid></oid><amount></amount></item>";
            }
            $xml.= "</itemlist>";
            $xml.= "</order>";
 
        }
        $xml.="</order_list></response>";
        return trim($xml);
    }

php解析xml数据并转换成数组。使用simplexml_load_string()转xml对象，json_encode()把对象转成json，json_decode()转成数组。

        simplexml_load_file()  加载xml url

        simplexml_load_string()  加载xml 字符串

1. <?php
2. $xml = ‘<?xml version=”1.0″ encoding=”utf-8″?>
3. <res>
4.     <name>test</name>
5.     <age>10</age>
6.     <sex>man</sex>
7. </res>’;
8. $xml =simplexml_load_string($xml); //xml转object
9. $xml= json_encode($xml);  //objecct转json
10. $xml=json_decode($xml,true); //json转array
11.  
12. var_dump($xml);

方法一:shuffle函数（打乱数组）和mt_rand函数（生成随机数，比rand速度快四倍）

/**
获得随机字符串
@param $len 需要的长度
@param $special 是否需要特殊符号
@return string 返回随机字符串
*/
function getRandomStr($len, $special=true){
$chars = array(
"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k",
"l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
"w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G",
"H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R",
"S", "T", "U", "V", "W", "X", "Y", "Z", "0", "1", "2",
"3", "4", "5", "6", "7", "8", "9"
);
if($special){
$chars = array_merge($chars, array(
"!", "@", "#", "$", "?", "|", "{", "/", ":", ";",
"%", "^", "&", "*", "(", ")", "-", "_", "[", "]",
"}", "<", ">", "~", "+", "=", ",", "."
));
}
$charsLen = count($chars) - 1;
shuffle($chars); //打乱数组顺序
$str = '';
for($i=0; $i<$len; $i++){
$str .= $chars[mt_rand(0, $charsLen)]; //随机取出一位
}
return $str;
}

方法二、str_shuffle函数（打乱字符串顺序）和mt_rand函数

//取随机10位字符串 
$strs="QWERTYUIOPASDFGHJKLZXCVBNM1234567890qwertyuiopasdfghjklzxcvbnm";
$name=substr(str_shuffle($strs),mt_rand(0,strlen($strs)-11),10);
echo $name;

方法三、md5(),uniqid(),microtime()生成唯一的32位字符串

$uniqid = md5(uniqid(microtime(true),true)); //microtime(true) 返回系统当前时间戳的毫秒数

其他方法:

/**
     * 方法一：获取随机字符串
     * @param number $length 长度
     * @param string $type 类型
     * @param number $convert 转换大小写
     * @return string 随机字符串
     */
    function random($length = 6, $type = 'string', $convert = 0)
    {
        $config = array(
            'number' => '1234567890',
            'letter' => 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
            'string' => 'abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ23456789',
            'all' => 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'
        );

        if (!isset($config[$type]))
            $type = 'string';
        $string = $config[$type];

        $code = '';
        $strlen = strlen($string) - 1;
        for ($i = 0; $i < $length; $i++) {
            $code .= $string{mt_rand(0, $strlen)};
        }
        if (!empty($convert)) {
            $code = ($convert > 0) ? strtoupper($code) : strtolower($code);
        }
        return $code;
    }

    /**
     * 方法二：获取随机字符串
     * @param int $randLength 长度
     * @param int $addtime 是否加入当前时间戳
     * @param int $includenumber 是否包含数字
     * @return string
     */
    function rand_str($randLength = 6, $addtime = 1, $includenumber = 0)
    {
        if ($includenumber) {
            $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQEST123456789';
        } else {
            $chars = 'abcdefghijklmnopqrstuvwxyz';
        }
        $len = strlen($chars);
        $randStr = '';
        for ($i = 0; $i < $randLength; $i++) {
            $randStr .= $chars[mt_rand(0, $len - 1)];
        }
        $tokenvalue = $randStr;
        if ($addtime) {
            $tokenvalue = $randStr . time();
        }
        return $tokenvalue;
    }