[Twisted-Python] regarding xml elements

Phil Christensen phil at bubblehouse.org
Sat Mar 29 20:56:56 EDT 2008

On Mar 28, 2008, at 7:33 PM, Jean-Paul Calderone wrote:
> On Fri, 28 Mar 2008 22:59:21 -0000, glyph at divmod.com wrote:
>> On 02:55 pm, exarkun at divmod.com wrote:
>>> On Fri, 28 Mar 2008 10:51:10 -0400, Phil Christensen  
>>> <phil at bubblehouse.org> wrote:
>>>> If it's so bad that you'd tell someone not to use it, why isn't  
>>>> it deprecated?
>>> Because it would take a lot of work to deprecate, and there are a  
>>> lot of
>>> other things people are working on that are deemed more important.
>> Also because there isn't a complete consensus on how terrible it  
>> is.  If you are doing advanced XML processing, it definitely isn't  
>> the best choice, because it's missing a bunch of features and it  
>> has some idiosyncratic behavior.  However, it is conveniently  
>> available without adding another dependency and it supports simple  
>> use-cases OK; this is still a problem with other XML libraries in  
>> Python, especially DOM libraries.  (For example, incompatibilities  
>> between the various lxml implementations.)
> Here's an example of a behavior it has which probably isn't going  
> to change
> any time soon:
>    >>> from twisted.web.microdom import parseString
>    >>> s = '<div><span>hello</span> <span>world</span></div>'
>    >>> parseString(s).toxml()
>    '<?xml version="1.0"?><div><span>hello</span><span>world</span></ 
> div>'
>    >>>
> So if you need such advanced XML features as correct whitespace  
> handling,
> steer clear. ;)

I have to say, I don't find this to be that big an issue. I think if  
you're using XML as a data interchange format (as I know the original  
poster was), whitespace is generally syntactically meaningless.

In fact, in my particular usage, I'm dealing with SAML responses  
which need to have a signature verified using xmlsec, and any  
whitespace like that would break the signature.

I know there's a tendency among developers to immediately disregard  
something that is less than perfect, but I like microdom too much to  
give up on it yet ;-)...


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