HTML form files validation

Do you have an elegant solution to validate server side a form containing more than one input type file under these conditions:

• If one the file is not valid user will have to upload another
• If one file if valid the server should keep it in memory so user don't have to upload it again.
• User may just abort and leave the page. Whatever has been saved on the server should be deleted.

As I example let's take a form containing 1 input type text and 2 inputs type file.

<input type="text" name="title" />
<input type="file" name="file1" />
<input type="file" name="file2" />

User submit a valid title, a valid file1 but invalid file2.

The goal here is to save each valid file until the form is valid or until session expires or something expires :)

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Suggestion 1

Generate a unique key for the user form (i.e form123) create a directory /tmp/uploads/form123 where valid file are saved.

A cron running every 10min go through all directories in /tmp/uploads/ and delete the one existing for more than 10min.