[Zope] Getting named variables passed to DTML callable

[Casey Duncan]

Phill Hugo wrote:
> 
> If there a simple way to get at the kw dict passed to a DTML callable?
> 
> I need to be able to determine if a variable was passed specifically
> from something like...
> 
> container.DTMLMethod(context, context.REQUEST, variable='Hello World')
> 
> In the DTML Method I can use <dtml-var variable> but if this variable
> was also the name of an id in the ZODB then it'll find it there.
> 
> Basically I need the equiv of <dtml-with kw only><dtml-var
> variable></dtml-with> ideally available as something like <dtml-var
> "this().kw"> or something
> 
> Thanks
> 
> Phill
> 

Looking at the source lends no obvious way. (As an exercise for the
reader, starting with OFS/DTMLMethod.py try to locate the actual python
source of the base class HTML...As my 3 year old son would say
psghetti!). Anyhow, I digress...

A method that comes to mind would be to check for the existence of an
equivilant value in the acquisition parent. If it either does not exist
or is a different value, then check for a property of that value (for
DTML docs). Again check if it exists or has a different value. Then do
the same for request. If all fail to give the value, it must have come
from a kw argument. I think you could write a python script like so:

arguments: name, value

if getattr(context.aq_parent, name, None) == value:
	return None
if hasattr(context.aq_explicit, 'propertysheets'):
	if context.getProperty(name, None) == value:
		return None
if context.REQUEST.get(name, None) == value:
	return None
return value

Of course this is not infallible, if you pass a name and value as a
keyword that happens to match the name and value of something else in
the namespace, it would return None.

Another alternative would be to write a custom dtml-tag that strips the
namespace down to the topmost one only for the code inside it. From what
I read, the kw dict is always the last thing pushed onto the namespace.
This assumes you haven't pushed anything yourself via dtml-let or
dtml-with.

A third option might be to wrap the method in a python script that
pushed kw onto the namespace. maybe call it kw_call:

arguments: DTMLMethod, **kw

kw['kw_args'] = kw
return DTMLMethod(_.None, context, kw=kw)

Then you would have a variable called kw_args available within the
method. I'm not entirely sure that this would work, but its worth a try!

-- 
| Casey Duncan
| Kaivo, Inc.
| cduncan@kaivo.com
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