Sell "links"

Hi,

Well, I think there is no problem doing this with HikaShop.
You could create one product for each course in HikaShop. And in each product, you would have the URL of the course as a file of the product under the "Files" area. After the purchase, the user would get a download button for the file of the product. Upon clicking on it, the user would be redirected to the URL of the course. You can also configure a menu item of the type HikaShop User Downloads which would list all the purchased downloads ( www.hikashop.com/support/documentation/5...nfig.html#main_files ).
So then, you can just change the text of the download button, and maybe some of the texts of the downloads area with translation overrides ( www.hikashop.com/download/languages.html#modify ), so that it matches with your terminology and that downloads become courses.
And if you want to make sure users don't purchase products more than once, you can use the "limit" system in HikaShop:
www.hikashop.com/support/2-uncategorised...limits-tutorial.html
Opening the course in a modal instead of a full page would require a view override of where the download links are displayed.

Hi,

If it's a PDF file, then you can directly upload the file in the Files area. If you have a checkout with registration, the download link will only work when the user is logged in with a user with a purchase for that download. So even if the user shares the download link, others won't be able to use it. They'll be redirected to a login page when trying to use it.

Now, if you want an iframe with the content in it, you would have to add this to Joomla articles.
You could use hkshow tags to restrict the display of the iframe in the article based on whether the current user purchased the corresponding product or not:
www.hikashop.com/home/blog/471-hikashop-4-4-3.html#tags
Something like this:

{hkshow bough="xx"}
<iframe ....>
</iframe>
{/hkshow}