Programming Forums > Script Programming > Python

Eragon229 · Aug 7th, 2005, 4:58 PM

Ok. I need a simple error trapping code please. And how do you place a program on a web page without it being a downloadable file? After I get my answers I'm out of your hair until I finish the tutorial. Which didn't have anything about error trapping. Thanks

Sane · Aug 8th, 2005, 12:19 AM

Error trapping code? You may have to be more specific. But you catch errors with try and except.

(Toggle Plain Text)

#invalid_variable = 42
try: print invalid_variable
except: print "Variable Doesn't Yet Exist"
print 'Done'

And for an ftp at least, you can go ...right click > properties > permission > uncheck read access... if you are the owner.

But that means no one can view or download it except you.

Cerulean · Aug 8th, 2005, 1:30 PM

Yes, try and except as shown in Sane's example, but make sure you tell the interpreter what kind of error you're excepting - faster to run, and faster to read (when you come back to a piece of code after months you won't be blindly asking yourself what kind of error you're trying to except).
In that example it would be:

(Toggle Plain Text)

try:
    print invalid_variable
except NameError:
    print "Variable doesn't exist yet.."

Quote:

And how do you place a program on a web page without it being a downloadable file?

Eh? You mean so that the script runs on the server and outputs information for your webpage? If so, you'll need a host that supports mod_python or supports CGI and has Python installed on the server.

Berto · Aug 9th, 2005, 2:58 AM

although i dont no if python has it, you should have a finally block, which is always run, to close db connections etc, and also a catchall exception otherwise there might be one you can miss.

Cerulean · Aug 9th, 2005, 1:48 PM

Yep, Python supports finally. As for a catchall exception.. probably not a good idea, as you won't know how precisely to clean up or fix the problem that's arisen.

Berto · Aug 10th, 2005, 2:34 AM

Yeah i understand that one, but i normally put one in for the errors i dont no that might occur to close the program effectivly and not have things still stuck in memory, and also log the error, for later purposes of fixing it.

Eragon229 · Aug 25th, 2005, 5:57 PM

Thanks guys.

Aug 7th, 2005, 4:58 PM	#1
Eragon229 Newbie Join Date: Jul 2005 Posts: 14 Rep Power: 0	Error Trapping and putting a program on a web site not as a file download. Ok. I need a simple error trapping code please. And how do you place a program on a web page without it being a downloadable file? After I get my answers I'm out of your hair until I finish the tutorial. Which didn't have anything about error trapping. Thanks __________________ Scientists prove this. Scientists prove that. They discover this, discover that. Though it seems there will be nothing left the discover, wrongo. Look beyond. I see no boundaries. The only boundaries, are your determination, your imagination, your intuition, and your knowledge. But it all started with a dream.

Aug 8th, 2005, 12:19 AM	#2
Sane Programming Guru Join Date: Apr 2005 Location: Waterloo, Ontario Posts: 1,868 Rep Power: 5	Error trapping code? You may have to be more specific. But you catch errors with try and except. (Toggle Plain Text) #invalid_variable = 42 try: print invalid_variable except: print "Variable Doesn't Yet Exist" print 'Done' #invalid_variable = 42 try: print invalid_variable except: print "Variable Doesn't Yet Exist" print 'Done' And for an ftp at least, you can go ...right click > properties > permission > uncheck read access... if you are the owner. But that means no one can view or download it except you. __________________ Waterloo's Canadian Computing Competition (CCC) - Stage 2 Problems, Solutions, and Test Data

Aug 9th, 2005, 2:58 AM	#4
Berto Programming Guru Join Date: Aug 2004 Posts: 1,022 Rep Power: 6	although i dont no if python has it, you should have a finally block, which is always run, to close db connections etc, and also a catchall exception otherwise there might be one you can miss. __________________ "Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. THAT'S relativity." - Albert Einstein

Aug 10th, 2005, 2:34 AM	#6
Berto Programming Guru Join Date: Aug 2004 Posts: 1,022 Rep Power: 6	Yeah i understand that one, but i normally put one in for the errors i dont no that might occur to close the program effectivly and not have things still stuck in memory, and also log the error, for later purposes of fixing it. __________________ "Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. THAT'S relativity." - Albert Einstein

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Aug 9th, 2005, 1:48 PM	#5
Cerulean Professional Programmer Join Date: Apr 2005 Location: London, England Posts: 459 Rep Power: 4	Yep, Python supports finally. As for a catchall exception.. probably not a good idea, as you won't know how precisely to clean up or fix the problem that's arisen.

Aug 25th, 2005, 5:57 PM	#7
Eragon229 Newbie Join Date: Jul 2005 Posts: 14 Rep Power: 0	Thanks guys.

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Programming Forums > Script Programming > Python

Error Trapping and putting a program on a web site not as a file download.