Some Questions

[Jug]

Hello,

I have some general questions:

1) How can the client call custom methods in my handler class?

2) Can I use my read method for registered and anonymous or do I have
to copy it to an AnonymousHandler?

3) How can I use the validate decorator (or a normal form) but allow
clients to change only one field (i.e. sending (new) data for only one
field)?


Regards
Jug

[jespern]

On Jul 6, 2:44 pm, Jug <j...@fantasymail.de> wrote:
> Hello,
>
> I have some general questions:
>
> 1) How can the client call custom methods in my handler class?

They can't. This is REST, not RPC. The only available methods you
have, are GET/POST/PUT and DELETE.

> 2) Can I use my read method for registered and anonymous or do I have
> to copy it to an AnonymousHandler?

Yes. Patches welcome.

> 3) How can I use the validate decorator (or a normal form) but allow
> clients to change only one field (i.e. sending (new) data for only one
> field)?

Hopefully I have a good answer for this one :-)

In piston.forms, there's a basic subclass of django.forms.ModelForm,
which has an additional method, namely 'merge_from_initial'. This
method will fill out the form based on the initial data it got, via
the initial keyword argument.

Untested code, but basically how you use it:

from piston.forms import ModelForm

class SomeForm(ModelForm):
...

@validate(SomeForm)
def update(self, request):
obj = get_object_or_404(...)
form = SomeForm(initial=obj)
form.merge_from_initial()

if form.is_valid(): # well, redundant really, since @validate
takes care of that
form.save()

That'll allow the client to only send one field, and the rest of the
values will be filled from the object.


HTH,

Jesper

[jug]

jespern wrote:
> On Jul 6, 2:44 pm, Jug <j...@fantasymail.de> wrote:
>
>> Hello,
>>
>> I have some general questions:
>>
>> 1) How can the client call custom methods in my handler class?
>>
>
> They can't. This is REST, not RPC. The only available methods you
> have, are GET/POST/PUT and DELETE.
>

Oh, yes, I misread the "resource methods".

>> 2) Can I use my read method for registered and anonymous or do I have
>> to copy it to an AnonymousHandler?
>>
>
> Yes. Patches welcome.
>

Works now with another base class with resource methods etc. for both
handlers.

>> 3) How can I use the validate decorator (or a normal form) but allow
>> clients to change only one field (i.e. sending (new) data for only one
>> field)?
>>
>
> Hopefully I have a good answer for this one :-)
>
> In piston.forms, there's a basic subclass of django.forms.ModelForm,
> which has an additional method, namely 'merge_from_initial'. This
> method will fill out the form based on the initial data it got, via
> the initial keyword argument.
>
> Untested code, but basically how you use it:
>
> from piston.forms import ModelForm
>
> class SomeForm(ModelForm):
> ...
>
> @validate(SomeForm)
> def update(self, request):
> obj = get_object_or_404(...)
> form = SomeForm(initial=obj)
> form.merge_from_initial()
>
> if form.is_valid(): # well, redundant really, since @validate
> takes care of that
> form.save()
>
> That'll allow the client to only send one field, and the rest of the
> values will be filled from the object.
>

Well, that did not work. :)
First, I had to convert some data to fit my form (eg user-ids to
usernames), then
the merge_from_initial helped me to get it working manually.

You should include that to the docs. (And it must be initial=[dict] or
instance=[obj].)
> HTH,
>
> Jesper
Thanks a lot,

Jug

[stephan preeker]

On Jul 6, 3:43 pm, jespern <jno...@gmail.com> wrote:
> On Jul 6, 2:44 pm, Jug <j...@fantasymail.de> wrote:
>
> > Hello,
>
> > I have some general questions:
>
> > 1) How can the client call custom methods in my handler class?
>
> They can't. This is REST, not RPC. The only available methods you
> have, are GET/POST/PUT and DELETE.
>
> > 2) Can I use my read method for registered and anonymous or do I have
> > to copy it to an AnonymousHandler?
>
> Yes. Patches welcome.

Since a normal Handler has an anonymous field which references to the
anonymoushandler i use that
to avoid code duplication:

class handler( .. )
...
def read(... id = id ):
self.anonymous.read( id = id )

[jespern]

On Jul 7, 12:13 pm, stephan preeker <spree...@gmail.com> wrote:
> On Jul 6, 3:43 pm, jespern <jno...@gmail.com> wrote:
> > > 2) Can I use my read method for registered and anonymous or do I have
> > > to copy it to an AnonymousHandler?
>
> > Yes. Patches welcome.
>
> Since a normal Handler has an anonymous field which references to the
> anonymoushandler i use that
> to avoid code duplication:
>
> class handler( .. )
>    ...
>    def read(... id = id ):
>        self.anonymous.read( id = id )

That's a very neat trick! I didn't even think about that.

This definitely belongs under the Tips & Tricks section. Adding it
now.


Jesper

[jug]

jespern wrote:
>> Since a normal Handler has an anonymous field which references to the
>> anonymoushandler i use that
>> to avoid code duplication:
>>
>> class handler( .. )
>> ...
>> def read(... id = id ):
>> self.anonymous.read( id = id )
>>
>
> That's a very neat trick! I didn't even think about that.
>
> This definitely belongs under the Tips & Tricks section. Adding it
> now.

Yes, but you have to return it:

def read(... id = id ):

return self.anonymous.read( id = id )

And to use the same resource methods:

class resourceMethods:
@classmethod
def myfield(cls, obj):
return obj.my_attribute

class anonymousHandler(resourceMethods, BaseHandler):
fields = (myfield, ...)
...

class handler(...):
anonymous = anonymousHandler
fields = (myfield, ...) # if its the same in both classes, also move
it to resourceMethods
...

[jug]

jug schrieb:

> Yes, but you have to return it:
>
> def read(... id = id ):
> return self.anonymous.read( id = id )

And create an instance of your AnonymousHandler:

def read(... id = id ):

return self.anonymous().read( id = id )