getimagesize(真实格式，支持base64)

代码：

/*

@desc：获取图片真实后缀

@param name 文件名

@return suffix 文件后缀

*/

function getimgsuffix($name) {

$info = getimagesize($name);

$suffix = false;

if($mime = $info['mime']){

$suffix = explode('/',$mime)[1];

}

return $suffix;

}

测试：

$suffix = getimgsuffix('http://192.168.8.81/public/image/01.jpg');

echo $suffix;

输出：

jpg

二进制方法(真实格式)

代码：

/*

@desc：获取文件真实后缀

@param name 文件名

@return suffix 文件后缀

*/

function getfilesuffix($name) {

$file = fopen($name, "rb");

$bin = fread($file, 2); // 只读2字节

fclose($file);

$info = @unpack("C2chars", $bin);

$code = intval($info['chars1'] . $info['chars2']);

$suffix = "unknow";

if($code == 255216){

$suffix = "jpg";

}elseif($code == 7173){

$suffix = "gif";

}elseif($code == 13780){

$suffix = "png";

}elseif($code == 6677){

$suffix = "bmp";

}elseif($code == 7798){

$suffix = "exe";

}elseif($code == 7784){

$suffix = "midi";

}elseif($code == 8297){

$suffix = "rar";

}elseif($code == 7368){

$suffix = "mp3";

}elseif($code == 0){

$suffix = "mp4";

}elseif($code == 8273){

$suffix = "wav";

}

return $suffix;

}

测试：

$suffix = getfilesuffix('http://192.168.8.81/public/image/01.jpg');

echo $suffix;

输出：

jpg

strrchr strrpos substr

$filename = "phpddt.jpg";

echo substr(strrchr($filename,"."),1);

?>

或

$filename = "phpddt.jpg";

echo substr($filename,strrpos($filename,".")+1);

?>

explode array_pop

$filename = "phpddt.jpg";

$arr = explode(".",$filename);

echo array_pop($arr);

?>

pathinfo

$filename = "phpddt.jpg";

$info = pathinfo($filename);

echo $info['extension'];

?>

或

$filename = "phpddt.jpg";

echo pathinfo($filename,PATHINFO_EXTENSION);

?>