DL, >> Nothing that can't be countered by keeping copies of the last X number of >> to-be-dowloaded-URLs files. > > That's a good idea, but how would the automated system 'know' to give-up > on the current file and utilise generation n-1? Unable to open the file or > ???
Well, that would be one reason for it. But there was also talk about integrity checking, both on the file and URL-entry level. Failing any of that could trigger it. But to be honest, I would not even automate it. Such a situation should not occur often, if at all. So having it is cause for concern, and should be investigated. Instead I would give the user an error message, and offer him the list of older files to choose one from to continue with (or have him specify the file on the commandline). > Using ctrl+c is a VERY BAD idea. To have it just exit the program ? Yes, indeed. Though you /could/ keep track of what needs to be finished and have the ctrl-c handler do that for you (barf). Another posibility is to capture the ctrl-c and set a flag, which than instructs the program to terminate loops wherever possible - and thus have the program finish as if there was no more to do. > (see also 'sledgehammer to crack a nut') While I agree with you there, I've been searching for other ways to detect a keypress (in a console-based script) and have found none. IOW, you do not (seem to) have another option. > Why do you need to abandon the process mid-way? Take your pick. Mostly because of "I need to leave *now*". Or perhaps because of an "you have X seconds before the device shuts down because of the battery being low" situation. > What is the OP's definition of "unlikely" or "acceptable risk"? Good question, but one I had no wish for to try to ascertain. I just gave some "worst case" secenario based replies (aka, the "did you think of <this> situation" kind). > There are so many reasons why such won't work first-time, when they should > every time; that it may be quite difficult to detect 'corruption' :-) That was not even considered. Just the "what do I still need to download" datafile. > Accordingly, there is no non-atomic transaction in the proposal The problem there is that you are second-guessing to what the OP will be writing, and that it will be good. I didn't and I don't assume that. I've seen too much "it works, so its good" noobie code. :-) > Do I want to deal with the complexities of managing files and corruptions, > in that arena? ... > Do you? :-) Its was-and-is not my choice to make. I gave the OP some stuff to think about, and left making the choice upto him. All three of the presented options are viable. > Be aware that formation rules for URLs are not congruent with OS FS rules! Yup. Though I seldom see that happen. Though I guess I should have mentioned that ... :-| Regards, Rudy Wieser -- https://mail.python.org/mailman/listinfo/python-list
