PadLoper supports selling digital downloads
By installing ProcessPadDownloads module you get new admin section under setup called PadLoper Downloads (you did know that it is possible to rename and -arrange these pages?). This section is super simple, it allows you to add, edit and remove digital downloads and define few rules for their accessibility.
In PadLoper it is separate process to attach these files into products. While two step process is somewhat clumsy when editing the products, it allows you to use same file in more than one product.
For attaching downloadable files into a project we need a downloads-field. So go ahead and install FieldtypeDownloads and create one field using that fieldtype. After attaching the new field into your product template, you can go edit your products and add one or more downloads per files. Currently it's using AsmSelect as an inputfield, but I am looking for supporting at least AutoComplete also, in case there are thousands of downloadables.
Securing the download files
ProcessPadDownloads saves the files inside /site/assets//. They are accessible by default, if you haven't set ProcessWire to secure the files. This can be done from /site/config.php by adding (or uncommenting) the line:
$config->pagefileSecure = true;
Then only roles which have access into admin can access the files directly. The actual url directly to a file is never visible to customer, so it won't be total disaster if pagefileSecure is not set true.
Delivery of the files
It's up to shipping module to offer the download links to customer, after succesful payment. Downloads are done using download codes, which have certain rules like "valid until" -date and max. download count. Download links have formation of www.yourshop.com/d/?code=23456789
If the download code is wrong or not valid anymore, then 404 page is send instead of file download. Currently ShippingEmail supports downloadable products.