使用php检查文件是否是kml文件

I am using move_file_upload on my server side in php so that client can allow users to upload their kml files to the server. I know that in order to check an image , in php I can use $check = getimagesize(file) but what would be the equivalent for a kml file check ?

I donot want to just check the extension of the file. I wish to know if infact the file is a valid kml file or not. If I only check the extension, someone can just post some other malicious file and change its extension to .kml

If you want to see if the file has the extension KML, you can use:

$filename = $_FILES["file"]["name"]; //or however you are getting the filename
$ext = end((explode(".",$filename)));

if($ext!="kml"){
    //Extension is incorrect
}

Checking mime content can be helpful. I am not quite sure what is the correct mime name of kml files but at least with checking in google it should be something as:

mime_content_type ($file) === 'application/vnd.google-earth.kml+xml'

How ever its possible that there are mimes set to 'application/xml' or 'text/xml' so extension validation is required as well ..