Part 4: Handling Errors the Way You Want

Whichever of PHP or CGI you used earlier in the tutorial, that is what you should troubleshoot next. We do this in a terminal shell, not in the web browser. For PHP, you will use the interpreter 'php5-cgi'. Naturally, CGI can be executed with the Python interpreter, but remember to hardwire the feed option into the program. Whichever you use, the terminal output should include feedback from the Python interpreter that reads similar to this:

Traceback (most recent call last):
File "./RSSReader.py", line 92, in ?
main()
File "./RSSReader.py", line 87, in main
output = formBody(feedname)
File "./RSSReader.py", line 82, in formBody
feedurl = feed.feeddata(feedname)
File "./RSSReader.py", line 53, in feeddata
feedaddress = feedinfo[feedname]
KeyError: ''

If you have read my tutorial on Python's exceptions, errors, and warnings, you know what KeyError means. If not, you will want to read that before going on from here. The next few pages will not make much sense otherwise.

• From the Basics to a Fully-Functional Program
• Illustrate the Problem With an Error
• Blackboxing the Error: HTML and PHP
• Reading Python's Error Message: Part 1
• Reading Python's Error Message: Part 2
• How to Handle the Error / Exception in Python
• A Fully-Functional Python Application at Last!