Using an array to check for valid file extensions in PHP

[Anthony2oo5]

Hey there,

I'm trying to write a script for uploading images but only with certain file extensions. Currently I have it working by:

[PHP]if (($FileExt = "jpg") || ($FileExt = "gif"))[/PHP]

ect, but is there a way i can do:

[PHP]$allowed = array("jpg", "gif");
if $allowed[/PHP]

I tried that but the if always turned out false.

What would be the correct way of doing this?

Thanks for your time.

[pbmods]

Changed thread title to better describe the problem.

Heya, Anthony2oo5.

The way I would do it:

[code=php]
$allowed = array(
'jpg' => true,
'gif' => true,
'etc' => true
);

if($allowed[$FileExt]) {
.
.
.
}
[/code]

The idea is that $allowed[$FileExt] will be true if $FileExt is an existing key in $allowed, but it will evaluate to false (null == false) if $FileExt does not exist in $allowed.

[Asterik]

One way I use is:

[code=php]
$allowed = array(".jpg", ".gif");
if(in_array(get FileExt())) ....
[/code]

and here's getFileExt() function:
[code=php]
function getFileExt($fil efield) {
/*************** *************** *************** *****
$pos: return the position of "." in file name
$filefield: name of your file upload file
*************** *************** *************** ****/
$pos = strpos(basename ($_FILES[$filefield]['name']),".");
$fileext = substr(basename ($_FILES[$filefield]['name']),$pos,strlen($ _FILES[$filefield]['name']));
return $fileext;
}
[/code]

[Anthony2oo5]

Hey thanks both I will try these solutions later.

I have a function for getting the file extension. I used one similar to what you have wrote but it didn't work for reading the file extension inside zip files, so I made another one:

[PHP] function GetFileExt($fil ename) {
return end(explode("." , $filename));
}[/PHP]

Thanks again, I will come back and update with my progress.

[Mathenge]

Thanks you helped alot i used this and working

//check valid file extensions only jpg,gif or png
function checkvalidext($ext) {
  $allowed = array(
     	'jpg'    =>    true,
    	'gif'    =>    true,
    	'png'    =>    true
 );
   if($allowed[$ext])
    {
	return true;
	} 
   else {
   return false;
   }   ;
   }
 //check valid file extensions only jpg,gif or png
function checkfilesize($x) {

   if($x< 1024000)
    {	return true;} 
   else { return false;
   } 
Then called these functions as
  $validfile = checkvalidext($ext);
  $validfilesize = checkfilesize($filesize);