[XML-SIG] processing "special characters" efficiently

[Goodger, David]

> From: Craig.Curtin@wdr.com
> Date: Thu, 6 Apr 2000 15:57:43 -0500
> 
> i'm looking for an efficient mechanism for filtering out
> XML special characters....
> 
> the following code executes in slo-mo, can anyone =20
> identify a more efficient way? this is obviously not
> optimal. any help is appreciated.
> 
> thanks,
> 
> craig
> 
> text2XMLSpecialCharacters=3D{   '&': '&', =20
>                         '<': '&lt;', =20
>                         '>': '&gt;', =20
>                   }
> 
> for k in text2XMLspecialChars.keys():
>       data =3D string.replace(data, k, text2XMLspecialChars[k])

This code has a dangerous logic bug. You cannot depend on the order of
dictionary keys; if '&' happened to come up last, then the input data =
"<you> & <me>" would produce the following output:

	&amp;lt;you&amp;gt; &amp; &amp;lt;me&amp;gt;

Which is probably not what you want. (I won't mention the variable name
problems.)

David Goodger
Systems Administrator, Advanced Systems
Automation Tooling Systems Inc., Automation Systems Division
direct: (519) 653-4483 ext. 2126    fax: (519) 653-8948
e-mail: dgoodger@atsautomation.com

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