beginner python cgi question

[Brandon Boles]

Hi folks,

I am trying to learn python, and have a form processing script giving me
this error:

Traceback (most recent call last):
File "inquiry", line 16, in ?
Address=fields["address"].value
File "/usr/local/python2.2/lib/python2.2/cgi.py", line 550, in __getitem__
raise KeyError, key
KeyError: address

This is the snippet of code the error is referring to:

....snip...
fields=cgi.Fiel dStorage()
if (fields.has_key ("name") and fields.has_key( "emailaddr" )):
SenderName=fiel ds["name"].value
Address=fields["address"].value
City=fields["city"].value
State=fields["state"].value
....snip...

I think what the problem is that if my form does not have one of the
fields (except 'name' and 'emailaddr') with data in it, I get this error.
What is the best way to fix this?

Please be kind, this is my first attempt at python. Thanks for the help!

Brandon

[Rene Pijlman]

Re: beginner python cgi question

Brandon Boles:[color=blue]
> Address=fields["address"].value[/color]
[...][color=blue]
>KeyError: address[/color]
[...][color=blue]
> if (fields.has_key ("name") and fields.has_key( "emailaddr" )):
> SenderName=fiel ds["name"].value
> Address=fields["address"].value
> City=fields["city"].value
> State=fields["state"].value
>...snip...
>
>I think what the problem is that if my form does not have one of the
>fields (except 'name' and 'emailaddr') with data in it, I get this error.
>What is the best way to fix this?[/color]

One way is to use if has_key(), as you already discovered. The other way
is exception handling:

try:
Address = fields["address"].value
except KeyError, e:
Address = None # and/or report an error
else:
# do something with Address

--
René Pijlman

[Jochen Wersdörfer]

Re: beginner python cgi question

+--[ Brandon Boles ]---[ email@nowhere.f oo ]
| ...snip...
| fields=cgi.Fiel dStorage()
| if (fields.has_key ("name") and fields.has_key( "emailaddr" )):
| SenderName=fiel ds["name"].value
| Address=fields["address"].value
| City=fields["city"].value
| State=fields["state"].value
| ...snip...
|
| I think what the problem is that if my form does not have one of the
| fields (except 'name' and 'emailaddr') with data in it, I get this error.
| What is the best way to fix this?

Getting a default value, if "address" is not set:

Address = fields.get("add ress", "n/a")

jochen

[Jochen Wersdoerfer]

Re: beginner python cgi question

+--[ Brandon Boles ]---[ email@nowhere.f oo ]
| ...snip...
| fields=cgi.Fiel dStorage()
| if (fields.has_key ("name") and fields.has_key( "emailaddr" )):
| SenderName=fiel ds["name"].value
| Address=fields["address"].value
| City=fields["city"].value
| State=fields["state"].value
| ...snip...
|
| I think what the problem is that if my form does not have one of the
| fields (except 'name' and 'emailaddr') with data in it, I get this error.
| What is the best way to fix this?

Getting a default value, if "address" is not set:

Address = fields.get("add ress", "n/a")

jochen

[Paolo G. Cantore]

Re: beginner python cgi question

Use 'fields=cgi.Fie ldStorage(keep-blank-values=1)' and you don't have to
worry about KeyErrors anymore.

Hope this helps.

Paolo

Brandon Boles wrote:[color=blue]
> Hi folks,
>
> I am trying to learn python, and have a form processing script giving me
> this error:
>
> Traceback (most recent call last):
> File "inquiry", line 16, in ?
> Address=fields["address"].value
> File "/usr/local/python2.2/lib/python2.2/cgi.py", line 550, in __getitem__
> raise KeyError, key
> KeyError: address
>
> This is the snippet of code the error is referring to:
>
> ...snip...
> fields=cgi.Fiel dStorage()
> if (fields.has_key ("name") and fields.has_key( "emailaddr" )):
> SenderName=fiel ds["name"].value
> Address=fields["address"].value
> City=fields["city"].value
> State=fields["state"].value
> ...snip...
>[/color]

[Andrew Clover]

Re: beginner python cgi question

Jochen Wersdörfer <jochen@helferl ein.net> wrote:
[color=blue]
> Address = fields.get("add ress", "n/a")[/color]

(You mean fields.getvalue , natch.)

If you don't want to have to deal with cgi returning a list sometimes, what
you really want is fields.getfirst ('fieldname', 'default'), but this only
exists in Python 2.2 onwards.

--
Andrew Clover
mailto:and@doxd esk.com

http://www.doxdesk.com/