How to force Chrome not to download files that have been already downloaded?

I prefer to work with PDF files in external PDF viewer (Foxit Reader), so I've set up Chrome to download files only and open them in Foxit Reader.

My download folder is constant, I don't need to specify the download path every time when I download something from the internet.

The problem is that Chrome automatically downloads the same file again if I've downloaded it before. As a result I have a lot of copies of the same file [file.pdf, file(1).pdf and so on] if I've searched for it several times.

Is there an option in chrome://flags or maybe an extension that checks the download folder for already existing files and stops downloading if some file with the same filename or hash is in the destination folder?

Solution 1:

Not sure, if there is a build in setting, but you could use the extension "Have I Downloaded This Before?"

Solution 2:

Found a nice extension called No More Dublicates that works exactly as I needed and starts downloading not immediately after clicking the link, but after a user's decision. From the description:

When initiating a download the extension will check if the file already exists. If it does exist, you will be provided with a few options whether you want to download it anyway or open the already existing file.