php 常用代码段

1.写文件

 $fp = fopen("jsapi_ticket.json", "w+");
 fwrite($fp, $str);
 fclose($fp);

2.导出数据（使用header函数）

header("Content-type: application/octet-stream");
header("Content-Disposition: attachment;filename=pc_collection_".$nodeid.'.txt');
echo base64_encode(json_encode($data));

3.解决base_decode 解密可能出现的中文乱码问题

mb_convert_encoding(base64_decode($v),"UTF-8","gb2312");

4.异或加密 解密

function xor_enc($str,$key){
	$crytxt = '';
	$keylen = strlen($key);
	for($i=0;$i<strlen($str);$i++){
		$k = $i % $keylen;
		$crytxt .= $str[$i] ^ $key[$k];
	}
	return $crytxt;
}

$str = "北京欢迎您";
$key = "Welcome";
$crytxt = xor_enc($str,$key);
echo "加密后->".$crytxt;
echo "<br>";
echo "解密后->".xor_enc($crytxt,$key);