Re: [Zope3-dev] Re: wildcard adapter
Marius Gedminas wrote: Now when you try to adapt anything to ITest, zope.component will call your ``adapter`` function and then check the return value. A return value of None means the adapter is not available, and results in a TypeError you see here: Yes, apologies, both you and Philipp are correct, I was trying to show a simple version of a problem and oversimplified. Here's what I really meant: from zope.component import provideAdapter from zope.interface import Interface from zope.component import getMultiAdapter class ITest(Interface): pass ... def adapter(*args): return args ... provideAdapter(adapter,adapts=(None,),provides=ITest) ITest(1) (1,) Yay, as expected... getMultiAdapter((1,),ITest) (1,) Good, still works... provideAdapter(adapter,adapts=(None,None),provides=ITest) getMultiAdapter((1,1),ITest) Traceback (most recent call last): ... zope.component.interfaces.ComponentLookupError: ((1, 1), InterfaceClass __main__.ITest, u'') Oh dear, what have I done wrong here? cheers, Chris -- Simplistix - Content Management, Zope Python Consulting - http://www.simplistix.co.uk ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
[Zope3-dev] Re: wildcard adapter
Marius Gedminas wrote: On Thu, Jan 18, 2007 at 08:55:17AM +, Chris Withers wrote: Marius Gedminas wrote: BTW passing interfaces to provideAdapter/adapts is out of fashion. This stuff is getting almost perl-ish in it's there's many ways to do it, pick the style you like nature.. There's a slight difference, I think. In the Zope 3 world, there's usually one style that is considered to be the best way of doing stuff. Only it varies with time and with individual Zope 3 developers. ;-) Well, I'm sure with Perl the best way of doing stuff also varies with time and with individual Perl developers. :) I agree the you should now not write this bit in ZCML but in the class itself is frustrating, as the other way isn't forbidden and there is endless example code out there which does it that way. Grok lets you write everything in the class and do away with the ZCML entirely. I believe this to be a superior pattern as it's quick to write, simple to understand and doesn't require switching context to another file to figure out what's going on. It also gives you error messages if you do something Grok cannot figure out. Regards, Martijn ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
[Zope3-dev] Re: wildcard adapter
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Chris Withers wrote: Marius Gedminas wrote: Now when you try to adapt anything to ITest, zope.component will call your ``adapter`` function and then check the return value. A return value of None means the adapter is not available, and results in a TypeError you see here: Yes, apologies, both you and Philipp are correct, I was trying to show a simple version of a problem and oversimplified. Here's what I really meant: from zope.component import provideAdapter from zope.interface import Interface from zope.component import getMultiAdapter class ITest(Interface): pass ... def adapter(*args): return args ... provideAdapter(adapter,adapts=(None,),provides=ITest) ITest(1) (1,) Yay, as expected... getMultiAdapter((1,),ITest) (1,) Good, still works... provideAdapter(adapter,adapts=(None,None),provides=ITest) getMultiAdapter((1,1),ITest) Traceback (most recent call last): ... zope.component.interfaces.ComponentLookupError: ((1, 1), InterfaceClass __main__.ITest, u'') Oh dear, what have I done wrong here? The order of your adapter registration is *one*, but you are trying to look it up against *two* objects (like a view). Tres. - -- === Tres Seaver +1 540-429-0999 [EMAIL PROTECTED] Palladion Software Excellence by Designhttp://palladion.com -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.2.2 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFFsSp++gerLs4ltQ4RApjSAKCYZwOp8b7LlUYEdk5E54bMSStY+ACgzdRY 8ZKbrbRcpyGUhel5YXXeuw4= =nAls -END PGP SIGNATURE- ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
[Zope3-dev] Re: wildcard adapter
Tres Seaver wrote: provideAdapter(adapter,adapts=(None,None),provides=ITest) getMultiAdapter((1,1),ITest) Traceback (most recent call last): ... zope.component.interfaces.ComponentLookupError: ((1, 1), InterfaceClass __main__.ITest, u'') Oh dear, what have I done wrong here? The order of your adapter registration is *one*, Does the following not register for an order of two? provideAdapter(adapter,adapts=(None,None),provides=ITest) cheers, Chris -- Simplistix - Content Management, Zope Python Consulting - http://www.simplistix.co.uk ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
Re: [Zope3-dev] Re: wildcard adapter
Philipp von Weitershausen wrote:
If it is, then which of the following should I use to register a
generic adapter for any single object to an interface:
provideAdapter(...,adapts=(None,),...)
This one.
Given that you can register adapters for any class, whether or not it
implements any interface, this doesn't work as it should:
from zope.component import provideAdapter
def adapter(*args): pass
...
from zope.interface import Interface
class ITest(Interface): pass
...
provideAdapter(adapter,adapts=(None,),provides=ITest)
ITest(1)
Traceback (most recent call last):
...
TypeError: ('Could not adapt', 1, InterfaceClass __main__.ITest)
class test: pass
...
ITest(test())
...
TypeError: ('Could not adapt', __main__.test instance at ...,
InterfaceClass __main__.ITest)
I have no idea what a generic adapter is, but the zope.component API
docs (== interfaces) are certainly complete in this sense. There are
also doctests.
Where can I find the docs and interfaces you mention above? I looked
through both zope.interface and zope.component and obviously missed them :-(
Chris
--
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- http://www.simplistix.co.uk
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Re: [Zope3-dev] Re: wildcard adapter
On Thu, Jan 18, 2007 at 08:53:36AM +, Chris Withers wrote:
Philipp von Weitershausen wrote:
If it is, then which of the following should I use to register a
generic adapter for any single object to an interface:
provideAdapter(...,adapts=(None,),...)
This one.
Given that you can register adapters for any class, whether or not it
implements any interface, this doesn't work as it should:
from zope.component import provideAdapter
def adapter(*args): pass
...
from zope.interface import Interface
class ITest(Interface): pass
...
provideAdapter(adapter,adapts=(None,),provides=ITest)
It's a bit subtle. The function you pass to provideAdapter is not the
adapter, it is an adapter factory. Consider the difference between
classes and objects. One is a factory for the other. Adapters are
usually objects, and but you register classes with provideAdapter.
Now when you try to adapt anything to ITest, zope.component will call
your ``adapter`` function and then check the return value. A return
value of None means the adapter is not available, and results in a
TypeError you see here:
ITest(1)
Traceback (most recent call last):
...
TypeError: ('Could not adapt', 1, InterfaceClass __main__.ITest)
This is useful when you want to have an adapter that is available
conditionally.
Insert a print statement in your adapter function, and you will see that
it does get called:
from zope.component import provideAdapter
def myAdapter(*args):
... print Hi
...
from zope.interface import Interface
class ITest(Interface): pass
...
provideAdapter(myAdapter,adapts=(None,),provides=ITest)
ITest(1)
Hi
Traceback (most recent call last):
File stdin, line 1, in ?
TypeError: ('Could not adapt', 1, InterfaceClass __main__.ITest)
I have no idea what a generic adapter is, but the zope.component API
docs (== interfaces) are certainly complete in this sense. There are
also doctests.
Where can I find the docs and interfaces you mention above? I looked
through both zope.interface and zope.component and obviously missed them :-(
src/zope/component/README.txt would be my guess. I do not remember
what's inside, I learnt adapters by osmosis and occasional studying of
the source code.
Marius Gedminas
--
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Re: [Zope3-dev] Re: wildcard adapter
On 18 Jan 2007, at 09:53 , Chris Withers wrote:
Philipp von Weitershausen wrote:
If it is, then which of the following should I use to register a
generic adapter for any single object to an interface:
provideAdapter(...,adapts=(None,),...)
This one.
Given that you can register adapters for any class, whether or not
it implements any interface, this doesn't work as it should:
from zope.component import provideAdapter
def adapter(*args): pass
...
This is your problem. The 'adapter' function is a factory so it's
supposed to actually return the value of the adaption. If ITest(1)
returns None, then the component architecture thinks adaption has
failed. This is a well-known and intended behaviour.
from zope.interface import Interface
class ITest(Interface): pass
...
provideAdapter(adapter,adapts=(None,),provides=ITest)
ITest(1)
Traceback (most recent call last):
...
TypeError: ('Could not adapt', 1, InterfaceClass __main__.ITest)
class test: pass
...
ITest(test())
...
TypeError: ('Could not adapt', __main__.test instance at ...,
InterfaceClass __main__.ITest)
I have no idea what a generic adapter is, but the zope.component
API docs (== interfaces) are certainly complete in this sense.
There are also doctests.
Where can I find the docs and interfaces you mention above? I
looked through both zope.interface and zope.component and obviously
missed them :-(
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[Zope3-dev] Re: wildcard adapter
Chris Withers wrote: Hi All, I was wondering if someone could give me a definitive explanation of what the following means: adapter for=* ISomething * ... ...means? Is the following equivalent: provideAdapter(...,adapts=(None,ISomething,None),...) ? Yes. If it is, then which of the following should I use to register a generic adapter for any single object to an interface: provideAdapter(...,adapts=(None,),...) This one. provideAdapter(...,adapts=None,...) This will give you most likely an error. I'm not having a lot of joy registering generic adapters so I thought I'd come and check my understanding here ;-) I have no idea what a generic adapter is, but the zope.component API docs (== interfaces) are certainly complete in this sense. There are also doctests. -- http://worldcookery.com -- Professional Zope documentation and training 2nd edition of Web Component Development with Zope 3 is now shipping! ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
[Zope3-dev] Re: wildcard adapter
Martin Aspeli wrote: Chris Withers wrote: Hi All, I was wondering if someone could give me a definitive explanation of what the following means: adapter for=* ISomething * ... ...means? Is the following equivalent: provideAdapter(...,adapts=(None,ISomething,None),...) No, but this is: provideAdapter(...,adapts=(Interface, ISomething, Interface),...) Actually, ZCML translates a * to None. And as of Zope 3.3, adapting None or Interface is equivalent. -- http://worldcookery.com -- Professional Zope documentation and training 2nd edition of Web Component Development with Zope 3 is now shipping! ___ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
