Working with encrypted files in Laravel (how to download decrypted file)

Question

In my webapp, users can upload files. Before being saved and stored, the contents of the file are encrypted using something like this:

Crypt::encrypt(file_get_contents($file->getRealPath()));

I then use the file system that comes with Laravel to move the file

Storage::put($filePath, $encryptedFile);

I have a table to store information about each file with columns such as:

• id
• file_path
• file_name
• original_name (includes the extension)

Now I want the user to be able to download this encrypted file. However, I'm having trouble decrypting the file and returning it to the user. In the file downloads response section of the Laravel documentation, it suggests to do this:

return response()->download($pathToFile, $name, $headers);

It wants a file path which is fine, but at which point can I decrypt the file contents so that it is actually readable?

I do seem to be able to do this:

$encryptedContents = Storage::get($fileRecord->file_path);
$decryptedContents = Crypt::decrypt($encryptedContents);

... but I don't know how to return it as a download with a specified file name.

Answer 1

You could manually create the response like so:

$encryptedContents = Storage::get($fileRecord->file_path);
$decryptedContents = Crypt::decrypt($encryptedContents);

return response()->make($decryptedContents, 200, array(
    'Content-Type' => (new finfo(FILEINFO_MIME))->buffer($decryptedContents),
    'Content-Disposition' => 'attachment; filename="' . pathinfo($fileRecord->file_path, PATHINFO_BASENAME) . '"'
));

You can check out the Laravel API for more info on what the parameters of the make method are. The pathinfo function is also used to extract the filename from the path so it sends the correct filename with the response.