Downloads restrictions through direct URL I am developing one feature in which user will get one pdf from my site, for this I have developed a process below,

1) user will click on the link and form open in popup

2) after submitting the form one link will be  sent to his email address

3) when user clicks on the link one small process of token check will be done and he will get the file

4) second time this link will not work

This whole process is working fine here my question is I want to restrict the user to get my files when user directly hit the URL link like www.mysite.com/files/downloads/abc.pdf

users can only be able to download it through that link which is in Email.

Thanks for  advance.
Not sure if this will help you, as I have never used it, but worth checking out:
Unique-download

Onetime download link is useful to create one-time download link,
similar to one time login. This will be helpful to send users one time
download links for e-commerce or download entities such as books, mp3
etc etc. considering them as file attachment for initial development.