I am using these Firefox preference setting for selenium in Python 2.7:
ff_profile = webdriver.FirefoxProfile(profile_dir)
ff_profile.set_preference("browser.download.folderList", 2)
ff_profile.set_preference("browser.download.manager.showWhenStarting", False)
ff_profile.set_preference("browser.download.dir", dl_dir)
ff_profile.set_preference('browser.helperApps.neverAsk.saveToDisk', "text/plain, application/vnd.ms-excel, text/csv, text/comma-separated-values, application/octet-stream")
With Selenium, I want to recurringly download the same file, and overwrite it, thus keeping the same filename – without me having to confirm the download.
With the settings above, it will download without asking for location, but all downloads will creates duplicates with the filename filename (1).ext, filename (2).ext etc in MacOS.
I'm guessing there might not be a setting to allow overwriting from within Firefox, to prevent accidents(?).
(In that case, I suppose the solution would be to handle the overwriting on the disk with other Python modules; another topic).