保持上传的文件跨多个页面

Question

I have a page that needs to accept .csv files with no predefined layout. That is, the user will choose what kind of data is in each column.

Right now, the upload file form sends me to a .php script which can access the uploaded file. It reads it, and lets the user assign categories to each of the columns. My next step is to copy the data from the .csv file to the database, but I'm not sure how to keep the file from being deleted from the temporary directory, I still need it on the next page where I do the actual copying. Also, I'm not interested in copying over the file to a different location on the server, it seems like a waste, and would be a hassle to do properly while allowing for concurrency.

How do I prevent the file from being deleted, or, alternatively, what's a better solution to this problem?

Answer 1

Well, I'm not sure this is maintainable without moving the uploaded file.

Personally, I would implement it thusly:

On the page that receives the uploaded file:

//assuming it hasn't already been started...
session_start();

//generate a unique filepath
$filepath = PATH_TO_THE_DIR . "/" . time() . 
"_" . md5_file($_FILES['formelement']['tmp_name']) . ".csv";

//move the uploaded file
move_uploaded_file($_FILES['formelement']['tmp_name'], $filepath);

//do whatever you need with the file, now at $filepath

//now store the filepath in the session:
$_SESSION['uploaded_filepath'] = $filepath;

session_write_close();

On the second page, when you want to do more processing:

//assuming it hasn't already been started...
session_start();

$filepath = $_SESSION['uploaded_filepath'];

// do whatever you need to with the file

unlink($filepath);

unset($_SESSION['uploaded_filepath']);

session_write_close();

That should be fine - obviously you would need to check permissions on the PATH_TO_THE_DIR constant, which will just be a directory somewhere.