PHP determines whether the uploaded file is legal

Sometimes we need to set up the backend so that users can only upload files with specified suffix names. At this time, the files need to be detected.

The code is as follows

/**
 * 获取文件后缀名,并判断是否合法
 *
 * @param string $file_name
 * @param array $allow_type
 * @return blob
*/
function get_file_suffix($file_name, $allow_type = array())
{
	$fnarray=explode('.', $file_name);
	$file_suffix = strtolower(array_pop($fnarray));
	if (empty($allow_type))
	{
		return $file_suffix;
	}
	else
	{
		if (in_array($file_suffix, $allow_type))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
}

Test

$allow_wj="jpg,gif,png,jpeg";
$allow=explode(",",$allow_wj); 

if (get_file_suffix("sakjdfk1.jpg",$allow)){
	echo "ok";
}else{
	echo "no";
}

Result

ok

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