Allow certain file types for upload

[zzz]

I have a form wher users can upload files. How do I restrict them to particular file types?

Also, I'd like to to check for file size and set file size restriction.

[tron00]

You can retrieve this type of information using ImageMagick. Once you have the information you need, you can create handlers with PHP.

[tron00]

Imagemagick works great for images. Otherwise you can use the filesize() function to determine a size and handle it appropriately.

[foyer]

or something like this

$type = substr($filename, -3);
if ($type == 'txt') {
//ok
} else {
//bad filetype
}

[rowanparker]

Remember file extensions can mean nothing in Linux.
You want to read the mime-type of the file.
I do not know how to do that (without looking it up).