I see that you can set where to download a file to through Webdriver, as follows:
fp = webdriver.FirefoxProfile()
fp.set_preference("browser.download.folderList",2)
fp.set_preference("browser.download.manager.showWhenStarting",False)
fp.set_preference("browser.download.dir",getcwd())
fp.set_preference("browser.helperApps.neverAsk.saveToDisk","text/csv")
browser = webdriver.Firefox(firefox_profile=fp)
But, I was wondering if there is a similar way to give the file a name when it is downloaded? Preferably, probably not something that is associated with the profile, as I will be downloading ~6000 files through one browser instance, and do not want to have to reinitiate the driver for each download.
I do not know if there is a pure Selenium handler for this, but here is what I have done when I needed to do something with the downloaded file.
Set a loop that polls your download directory for the latest file that does not have a .part extension (this indicates a partial download and would occasionally trip things up if not accounted for. Put a timer on this to ensure that you don't go into an infinite loop in the case of timeout/other error that causes the download not to complete. I used the output of the ls -t <dirname> command in Linux (my old code uses commands, which is deprecated so I won't show it here :) ) and got the first file by using
# result = output of ls -t
result = result.split('\n')[1].split(' ')[-1]
If the while loop exits successfully, the topmost file in the directory will be your file, which you can then modify using os.rename (or anything else you like).
Probably not the answer you were looking for, but hopefully it points you in the right direction.