Re: [Zope-dev] The Application object
Yves-Eric Martin wrote: Shane Hathaway [EMAIL PROTECTED] wrote: You *must* remember to close the connection: app._p_jar.close() This is not mentionned in the above document, so I was doing without so far, and did not run into any problem. Now that I see it, I believe this is the Right Thing to Do and will include it in the release. But since you put an emphasis on its being required, can you tell us what evil things may happen if you don't close the connection? (Consuming ressources?) That's correct. Only a certain number of connections are allowed at a time. Currently, as the "app" object falls out of scope it should close the connection automatically, but that may not always be the case IMHO. BTW if you're using this technique, be sure you're not opening two connections in one thread. It can prove hazardous. Shane ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
RE: [Zope-dev] The Application object
I'm not sure I understand. What is AppSingleton? What does the Instance() method do? -Original Message- From: Jeff K. Hoffman [mailto:[EMAIL PROTECTED]] Sent: Monday, July 17, 2000 11:54 AM To: [EMAIL PROTECTED] Subject: [Zope-dev] The Application object Hello, What is the easiest way for me to get ahold of the Application object at run-time? I am writing a Product that needs to access some things in the Control_Panel, and need the app object to get there. I know how to do it given a reference to an object in the ZODB (getPhysicalRoot(), etc.), but need a way to do it given no references. I need something like: import AppSingleton app = AppSingleton.Instance() app.Control_Panel.blah --Jeff --- Jeff K. Hoffman 704.849.0731 x108 Chief Technology Officer mailto:[EMAIL PROTECTED] Going Virtual, L.L.C. http://www.goingv.com/ ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope ) ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
RE: [Zope-dev] The Application object
On Mon, 17 Jul 2000, Chris McDonough wrote:
I'm not sure I understand. What is AppSingleton? What does the
Instance() method do?
Sorry I wasn't clear enough. The Singleton is a design pattern from the
Gang of Four book that fits this situation well. It is a class that is
meant to control access to the one and only instance of a global
variable. I was just using that as a frame of reference, though; Zope has
no such class for the Application object, or I wouldn't be writing this
message.
I just need some way of getting at the one and only Application object at
run-time. Something like:
from Globals import app
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
...
Given a reference to an object in the ZODB, I can do this via:
app = self.getPhysicalRoot()
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
But, this does not work from methods like __init__, or __setstate__, where
we do not have a physical location in the ZODB, yet.
I just need a reference to the app object. I know the answer has to be
simple, but I can't find it.
--Jeff
---
Jeff K. Hoffman 704.849.0731 x108
Chief Technology Officer mailto:[EMAIL PROTECTED]
Going Virtual, L.L.C. http://www.goingv.com/
___
Zope-Dev maillist - [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope-dev
** No cross posts or HTML encoding! **
(Related lists -
http://lists.zope.org/mailman/listinfo/zope-announce
http://lists.zope.org/mailman/listinfo/zope )
RE: [Zope-dev] The Application object
Sorry I wasn't clear enough. The Singleton is a design
pattern from the
Gang of Four book that fits this situation well. It is a
class that is
meant to control access to the one and only instance of a global
variable. I was just using that as a frame of reference,
though; Zope has
no such class for the Application object, or I wouldn't be
writing this
message.
Oh, ok, sorry, hard to tell intent from actual code. :-)
I just need some way of getting at the one and only
Application object at
run-time. Something like:
from Globals import app
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
...
Given a reference to an object in the ZODB, I can do this via:
app = self.getPhysicalRoot()
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
But, this does not work from methods like __init__, or
__setstate__, where
we do not have a physical location in the ZODB, yet.
Ah, I see the problem.
I'm afraid I don't know the answer.
I generally use the manage_afterAdd and manage_beforeDelete methods to
do things like this.
I suppose you could pass the root object into the constructor.
__setstate__... well. Err...
Anybody else?
___
Zope-Dev maillist - [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope-dev
** No cross posts or HTML encoding! **
(Related lists -
http://lists.zope.org/mailman/listinfo/zope-announce
http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] The Application object
Chris McDonough wrote:
Sorry I wasn't clear enough. The Singleton is a design
pattern from the
Gang of Four book that fits this situation well. It is a
class that is
meant to control access to the one and only instance of a global
variable. I was just using that as a frame of reference,
though; Zope has
no such class for the Application object, or I wouldn't be
writing this
message.
Oh, ok, sorry, hard to tell intent from actual code. :-)
I just need some way of getting at the one and only
Application object at
run-time. Something like:
from Globals import app
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
...
Given a reference to an object in the ZODB, I can do this via:
app = self.getPhysicalRoot()
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
But, this does not work from methods like __init__, or
__setstate__, where
we do not have a physical location in the ZODB, yet.
Ah, I see the problem.
I'm afraid I don't know the answer.
I generally use the manage_afterAdd and manage_beforeDelete methods to
do things like this.
I suppose you could pass the root object into the constructor.
__setstate__... well. Err...
Anybody else?
The way to get the root application object is to open a connection to
the ZODB and get the 'Application' object from the list of root
objects. There is an easy shortcut:
import Zope
app = Zope.app()
app now refers to a *copy* of the root Application object. When you're
done modifying it and its descendants you have to commit or abort the
transaction.
get_transaction().commit() (or abort())
This gives you all kinds of benefits like undo and elimination of
threading conflicts. You *must* remember to close the connection:
app._p_jar.close()
Shane
___
Zope-Dev maillist - [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope-dev
** No cross posts or HTML encoding! **
(Related lists -
http://lists.zope.org/mailman/listinfo/zope-announce
http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] The Application object
On Mon, 17 Jul 2000, Shane Hathaway wrote:
The way to get the root application object is to open a connection to
the ZODB and get the 'Application' object from the list of root
objects. There is an easy shortcut:
import Zope
app = Zope.app()
app now refers to a *copy* of the root Application object.
Yeehaw, that worked! I was so close. :-)
When you're done modifying it and its descendants you have to commit or
abort the transaction.
[snip]
Do I need to commit or abort even if I don't make changes to the
application object? The only thing I need it for is to get to the
Control_Panel; I am instantiating ZClass instances in the constructor of a
Python class, i.e.:
class MyClass:
def __init__(self, id, title=''):
import Zope
app = Zope.app()
ob = app.Control_Panel.Products.MyProduct.MyZClass('newId')
ob.id = 'newId'
self._setObject('newId', ob)
# Do I need a get_transaction().abort() here? Will that not abort
# the wrong transaction?
app._p_jar.close()
...
This gives you all kinds of benefits like undo and elimination of
threading conflicts.
[snip]
Good stuff. Thanks, Shane.
Shane
--Jeff
---
Jeff K. Hoffman 704.849.0731 x108
Chief Technology Officer mailto:[EMAIL PROTECTED]
Going Virtual, L.L.C. http://www.goingv.com/
___
Zope-Dev maillist - [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope-dev
** No cross posts or HTML encoding! **
(Related lists -
http://lists.zope.org/mailman/listinfo/zope-announce
http://lists.zope.org/mailman/listinfo/zope )
RE: [Zope-dev] The Application object
So it's kosher then to reimport the Zope module and use app() in a
constructor method, Shane? I was always afraid it would do something
horrible.
-Original Message-
From: Jeff K. Hoffman [mailto:[EMAIL PROTECTED]]
Sent: Monday, July 17, 2000 1:11 PM
To: Shane Hathaway
Cc: Chris McDonough; 'Jeff K. Hoffman'; [EMAIL PROTECTED]
Subject: Re: [Zope-dev] The Application object
On Mon, 17 Jul 2000, Shane Hathaway wrote:
The way to get the root application object is to open a
connection to
the ZODB and get the 'Application' object from the list of root
objects. There is an easy shortcut:
import Zope
app = Zope.app()
app now refers to a *copy* of the root Application object.
Yeehaw, that worked! I was so close. :-)
When you're done modifying it and its descendants you have
to commit or
abort the transaction.
[snip]
Do I need to commit or abort even if I don't make changes to the
application object? The only thing I need it for is to get to the
Control_Panel; I am instantiating ZClass instances in the
constructor of a
Python class, i.e.:
class MyClass:
def __init__(self, id, title=''):
import Zope
app = Zope.app()
ob = app.Control_Panel.Products.MyProduct.MyZClass('newId')
ob.id = 'newId'
self._setObject('newId', ob)
# Do I need a get_transaction().abort() here? Will that
not abort
# the wrong transaction?
app._p_jar.close()
...
This gives you all kinds of benefits like undo and elimination of
threading conflicts.
[snip]
Good stuff. Thanks, Shane.
Shane
--Jeff
---
Jeff K. Hoffman 704.849.0731 x108
Chief Technology Officer
mailto:[EMAIL PROTECTED]
Going Virtual, L.L.C. http://www.goingv.com/
___
Zope-Dev maillist - [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope-dev
** No cross posts or HTML encoding! **
(Related lists -
http://lists.zope.org/mailman/listinfo/zope-announce
http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] The Application object
On Mon, Jul 17, 2000 at 12:21:42PM -0400, Jeff K. Hoffman wrote:
On Mon, 17 Jul 2000, Chris McDonough wrote:
I'm not sure I understand. What is AppSingleton? What does the
Instance() method do?
Sorry I wasn't clear enough. The Singleton is a design pattern from the
Gang of Four book that fits this situation well. It is a class that is
meant to control access to the one and only instance of a global
variable. I was just using that as a frame of reference, though; Zope has
no such class for the Application object, or I wouldn't be writing this
message.
I just need some way of getting at the one and only Application object at
run-time. Something like:
from Globals import app
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
...
Given a reference to an object in the ZODB, I can do this via:
app = self.getPhysicalRoot()
myOb = app.Control_Panel.Products.MyProduct.MyZClass('foo')
But, this does not work from methods like __init__, or __setstate__, where
we do not have a physical location in the ZODB, yet.
I just need a reference to the app object. I know the answer has to be
simple, but I can't find it.
See the __init__.py method of ZScheduler, which can be found on Zope.org.
ZScheduler uses a Singleton as well.
--
Martijn Pieters
| Software Engineermailto:[EMAIL PROTECTED]
| Digital Creations http://www.digicool.com/
| Creators of Zope http://www.zope.org/
| ZopeStudio: http://www.zope.org/Products/ZopeStudio
-
___
Zope-Dev maillist - [EMAIL PROTECTED]
http://lists.zope.org/mailman/listinfo/zope-dev
** No cross posts or HTML encoding! **
(Related lists -
http://lists.zope.org/mailman/listinfo/zope-announce
http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] The Application object
On Mon, 17 Jul 2000 12:50:27 -0400 Shane Hathaway [EMAIL PROTECTED] wrote: import Zope app = Zope.app() get_transaction().commit() I am doing just that in the next version of zzLocale (Zope interface internationalization product) I was about to release. I figured it out from the "Zope Debugging" doc (http://www.zope.org/Documentation/Misc/DEBUGGING.txt), but: You *must* remember to close the connection: app._p_jar.close() This is not mentionned in the above document, so I was doing without so far, and did not run into any problem. Now that I see it, I believe this is the Right Thing to Do and will include it in the release. But since you put an emphasis on its being required, can you tell us what evil things may happen if you don't close the connection? (Consuming ressources?) -- Yves-Eric Martin Digital Garage Inc. [EMAIL PROTECTED] ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
