I prefer Preview as my default PDF viewer. However, there are certain PDFs that I need to open in Adobe Acrobat DC for some work things. All of these files that I need to open in Acrobat come from a limited number of websites where I download them.
What I think I want to set up is folder action that sees that a file was downloaded from a certain website and then automatically opens that file in a certain app (in this case, Acrobat). But for anything that doesn’t meet this specific criteria, it would just save the file as normal for me to open when I want to with Preview as the default app.
I know how to make folder actions in Automator. But I don’t see a way for the action to be based on the file download location. However, this location is stored in the file’s metadata, as seen in Get Info » More Info » Where from (it lists the URL).