[Zope-dev] Question to acquisition

[Jim Fulton]

Thomas Riedl wrote:
> 
> Hello Jim,
> 
> I've been able to overcome my problem, but - honestly - I still do
> not understand how and why it works this and breaks that way.
> 
> Just to sum up:
> I've a product, called SDB.
> It has a class SDB, whose instances are publisheable (right term?).
> This class inherits among others from Acquisition.Implicit.
> Still using Zope-1.10.2, SuSe-5.1, "python serve.py".
> 
> I've a DTML form which I want to parameterize and return upon
> python code actions, like if a 'change this' method is called, it
> 'returns' depending on its results an 'OK' button or a 'Go there, again!'
> button; let's call it 'sdb_button.dtml'.
> It also contains a line "<!--#var standard_html_header-->".
> 
> The class 'SDB' has a (callable) attribute
>         TEST=HTMLFile('sdb_button', globals(),
>                 <some argument defaults by keywords>)
> 
> It also has some method
>         def change_things(....):
>                 ...
>                 return self.TEST(
>                         self.aq_parent, # relevant stuff

Have you tried passing just self? If the object is an 
Implicit acquirer, then you shouldn't need to get aq_parent.

>                         <several arguments by keywords>
>                         )
> Now, if I call "http://...../instance1/TEST", I get what I want.

ZPublisher automatically passes self to test when calling TEST.
It does this, because DocumentTemplates have the argument 'self'
in their signatures.

> If I call ..../instance1/change_things, I get what I want, too.
> 
> But: If I leave out the 'self.aq_parent' argument, change_things() chokes
> on a key error since it doesn't know about standard_html_header.

Right.  Where else would it get standard_html_header?
 
> So, I work around my problem and insert self.aq_base, but I don't

You mean self.aq_parent, but self should do.

> understand why TEST works without and change_things doesn't.

Because ZPublisher passes self to TEST and change_thing neeeds to 
too.

Jim

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