PHP判断文件类型

```php
$str = "http://qnshilv.lq1008.xyz/uploads/20201219/10f519574cf2cbd40d55f9c3fc7b48f4.mp4";
function file_format($str){
    // 取文件后缀名
    $str=strtolower(pathinfo($str, PATHINFO_EXTENSION));
    // 图片格式
    $image=array('webp','jpg','png','ico','bmp','gif','tif','pcx','tga','bmp','pxc','tiff','jpeg','exif','fpx','svg','psd','cdr','pcd','dxf','ufo','eps','ai','hdri');
    // 视频格式
    $video=array('mp4','avi','3gp','rmvb','gif','wmv','mkv','mpg','vob','mov','flv','swf','mp3','ape','wma','aac','mmf','amr','m4a','m4r','ogg','wav','wavpack');
    // 压缩格式
    $zip=array('rar','zip','tar','cab','uue','jar','iso','z','7-zip','ace','lzh','arj','gzip','bz2','tz');
    // 文档格式
    $text=array('exe','doc','ppt','xls','wps','txt','lrc','wfs','torrent','html','htm','java','js','css','less','php','pdf','pps','host','box','docx','word','perfect','dot','dsf','efe','ini','json','lnk','log','msi','ost','pcs','tmp','xlsb');
    // 匹配不同的结果
    switch ($str) {
        case in_array($str, $image):
            return 'image';
            break;
        case in_array($str, $video):
            return 'video';
            break;
        case in_array($str, $zip):
            return 'zip';
            break;
        case in_array($str, $text):
            return 'text';
            break;
        default:
            return 'image';
            break;
    }
}

```