Re: [Zope-dev] ZPatterns question
Christian Scholz wrote: yeah, this is exactly what I'm after too. I'd like the virtual objects the specialist is responsible for to have normal Zope management screens. Well, I think this shouldn't be too difficult to create. Just a subclass of Specialist and add some Contents-Tab, define objectIds() etc. in the Methods tab and call it in the management screen of "Contents". Though the more advanced things like Copy/Paste/Rename might then not be available.. But for me actually it would be sufficient to get the contents. :-S I was hoping for something along the lines of subclass from Specialist and Folder, and override objectIds (+ whatver else?) in my new class to do 'the right thing' I wonder how that would pan out? Also, much mroe trickily, I'd like them to be able to contain each other, although Steve A's __bobo_traverse__ trick might help with this bit... What do you mean? Nesting Specialists (or these virtual folder specialists)? The DataSkins stored in the specialist ;-) cheers, Chris ___ 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] ZPatterns question
Christian Scholz wrote: Well, virtual in the sense as a specialist is no real folder but can provide content from different sources. Thus what I mean is some mechanism which emulates objectIds() etc. so it looks to the user (and the ones using it via dtml) like a normal folder object. Somehow like the Customizer but without the need for actually creating Zope objects. Something inbetween Specialist and Customizer this would be I guess. yeah, this is exactly what I'm after too. I'd like the virtual objects the specialist is responsible for to have normal Zope management screens. Also, much mroe trickily, I'd like them to be able to contain each other, although Steve A's __bobo_traverse__ trick might help with this bit... cheers, Chris ___ 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] ZPatterns question
Hi! Well, virtual in the sense as a specialist is no real folder but can provide content from different sources. Thus what I mean is some mechanism which emulates objectIds() etc. so it looks to the user (and the ones using it via dtml) like a normal folder object. Somehow like the Customizer but without the need for actually creating Zope objects. Something inbetween Specialist and Customizer this would be I guess. yeah, this is exactly what I'm after too. I'd like the virtual objects the specialist is responsible for to have normal Zope management screens. Well, I think this shouldn't be too difficult to create. Just a subclass of Specialist and add some Contents-Tab, define objectIds() etc. in the Methods tab and call it in the management screen of "Contents". Though the more advanced things like Copy/Paste/Rename might then not be available.. But for me actually it would be sufficient to get the contents. Also, much mroe trickily, I'd like them to be able to contain each other, although Steve A's __bobo_traverse__ trick might help with this bit... What do you mean? Nesting Specialists (or these virtual folder specialists)? cheers, Christian -- COM.lounge http://comlounge.net/ communication design [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 )
Re: [Zope-dev] ZPatterns question
Hi! Actually should answer to these posts... ;-) On Thu, Dec 28, 2000 at 03:11:37PM -0500, Steve Spicklemire wrote: Hi Christian, Well, nobody else answered that I saw... so I'll take a crack at your questions "CS" == Christian Scholz [EMAIL PROTECTED] writes: CS Hi there! CS Finally I managed to get a basic understanding of how to do CS things with ZPatterns ;-) So seems quite cool :) (and CS hopefully I find some time to write some basic howto about it) CS But I have some little questions: CS 1. Is it possible to retrieve the set of known IDs from a CS specialist? Or would I need to add my own method to it which CS does this (and change it accordingly if I switch to another CS storage method)? If you store persistently you can use the Rack's method: "defaultRack.getPersistentItemIDs()" Thanks, also found this out in the meanwhile. but a couple of notes: 1) this returns a BTree object, not a simple list, so you can't iterate through it in DTML. You'll need to copy it to a simple list for that.. and 2) If you change to a different storage you'll need to create your own method (ZSQL Method?). What I've found is that if you have a large number of objects you'll either want to query a Catalog, or an SQL database to get Ids that match some criteria that limit the number of hits to something that makes sense to display in a browser. I am now using some method I create inside the specialist for it. CS 2. Is it planned to provide something like a virtual folder CS which acts like a normal object manager but is controlled via CS ZPatterns (so actually something like Folder with Customizer CS Support just without the "anchor" in ZODB. (would also CS require some mechanism asked for in 1.) Hmmm... I'm not sure what you're after here. Why not just use a Specialist? In what sense do you want it to be virtual? Well, virtual in the sense as a specialist is no real folder but can provide content from different sources. Thus what I mean is some mechanism which emulates objectIds() etc. so it looks to the user (and the ones using it via dtml) like a normal folder object. Somehow like the Customizer but without the need for actually creating Zope objects. Something inbetween Specialist and Customizer this would be I guess. (Are you looking for a dynamic traversal interface that would allow you to map URLs to objects that are managed by ZPatterns? Can you give an example?) yes, something like this comes close I guess. e.g. I have some sql database consisting of people's addresses and I want to create some specialist which queries this database (or how ever this specialist is configured right now in order to get the object ids) and shows it as if it's a normal folder. (seems to me more transparent at some point). But I assume it's not suited for all applications e.g. if the number of objects gets a little bigger. And I guess I can create this myself if I subclass from Specialist and add the rest of the ObjectManager's interface to it. CS 3. Is it possible to use ZPatterns also without some exta CS ZClass defined in a Product? At least if I don't need methods CS for my objects but simple want to define the attribute they CS know. Would be nice as I could then hold everything together CS in one place (the specialist that is) without requiring to CS install something also in the Products folder of the Control CS Panel. I believe you need to either create a Python subclass, or a ZClass subclass of DataSkin. "Raw" DataSkins don't have the right permissions to allow for TTW access. If you're creating a 'product' anyway... just make a 'dummy' class that you can use for storage. ok, but I still need to define the attributes I want to handle inside a propertysheet of this ZClass, right? Actually what I would like is something which directly resides inside the Specialist and not somewhere outside in some Product folder. So everything is close together in one place. CS That's it for now, I will keep experimenting then.. :) Good Luck! Oh, it's working better than I thought :) but thanks, christian ___ 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] ZPatterns question
Hi Steve! On Thu, Dec 28, 2000 at 10:45:46PM +, Steve Alexander wrote: Steve Spicklemire wrote: CS 2. Is it planned to provide something like a virtual folder CS which acts like a normal object manager but is controlled via CS ZPatterns (so actually something like Folder with Customizer CS Support just without the "anchor" in ZODB. (would also CS require some mechanism asked for in 1.) Hmmm... I'm not sure what you're after here. Why not just use a Specialist? In what sense do you want it to be virtual? (Are you looking for a dynamic traversal interface that would allow you to map URLs to objects that are managed by ZPatterns? Can you give an example?) Reading this just after reading the source to Specialists.py, I had a thought; and tried it out; and it works! :-) You can use SkinScript to define __bobo_traverse__ for a particular kind of DataSkin in a Specialist. For example: WITH SELF COMPUTE __bobo_traverse__=traversal_method that's very cool :) I just created some base class for this from which my ZClasses are derived but nice to know that it's also possible without this base class. (though for this application it's easier with this base class as it's easier to configure then) cheers, Christian ___ 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] ZPatterns question
Steve Spicklemire wrote: CS 2. Is it planned to provide something like a virtual folder CS which acts like a normal object manager but is controlled via CS ZPatterns (so actually something like Folder with Customizer CS Support just without the "anchor" in ZODB. (would also CS require some mechanism asked for in 1.) Hmmm... I'm not sure what you're after here. Why not just use a Specialist? In what sense do you want it to be virtual? (Are you looking for a dynamic traversal interface that would allow you to map URLs to objects that are managed by ZPatterns? Can you give an example?) Reading this just after reading the source to Specialists.py, I had a thought; and tried it out; and it works! :-) You can use SkinScript to define __bobo_traverse__ for a particular kind of DataSkin in a Specialist. For example: WITH SELF COMPUTE __bobo_traverse__=traversal_method Then, define a method in the specialist (or rack) called traversal_method. I used a PythonScript, and gave it the parameter list "REQUEST, name". Make your method return the appropriate object to traverse to from your DataSkin, depending on the name passed. Something like return getattr(container.path.to.somewhere, name) That's the simple version, and it won't give the traversed-to object the correct context most of the time. To do that, I'd need to use an external method, and use the __of__ method to give the returned object an appropriate context. However, it is a start, and proves that it can be done. Take a look in the __bobo_traverse__ method of Specialists.py (from ZPatterns) for a good algorithm for traversal. The variable _marker is almost always a class attribute initialized to [], to make a unique object, as a sentinel. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ 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] ZPatterns question
Steve Alexander wrote: return getattr(container.path.to.somewhere, name) That's the simple version, and it won't give the traversed-to object the correct context most of the time. To do that, I'd need to use an external method, and use the __of__ method to give the returned object an appropriate context. However, if all you are doing is saying "does this object have the named attribute? if not, get it from another specialist", and you're using Specialist.getItem() to do the latter part, then the object you want comes ready-wrapped in the appropriate context, courtesy of the Rack that gives it to you! -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ 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] ZPatterns Question - Talking to a Specialist....
Hmm... this is probably more of a plain Zope question than a ZPatterns question.. but since I'm *using* ZPatterns, I thought I'd check what other folks are doing to implement apps with ZPatterns. I've been creating Specialists with DataSkin subclassed objects in their defaultRacks. The methods of the objects are pretty easy, I can put them in the ZClass, or the Product class that I'm sub-ZClassing from. But since my Specialists are just 'plain' objects I can only make methods of Specialists as 'DTML Methods' or 'Python Methods'. I'd love to call these methods as: dtml-in "TableManager.getAllProductCategories(_.None, _)" but this doesn't work. The current namespace doesn't include any of the queries or other methods that I need to *implement* getAllProductCategories.. so I end up doing: dtml-with TableManager dtml-in "getAllProductCategories(_.None, _)" ... but this seems obtuse when the TableManager needs to talk to the ProductManager or other managers I end up with a *lot* of dtml-with... statements! What are other folks doing? thanks, -steve ___ 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] ZPatterns Question
At 11:58 PM 8/9/00 +0100, Steve Alexander wrote: 1: ZClass instances can have PropertySheets added to them, independently of any sheets declared in the ZClass class definition. I've been working with Zope for a while, but this had never occurred to me. I guess this is just another one of those hangovers from writing in Java for so long. It's not a very well-known feature of Zope. AFAIK, it was implemented to support WebDAV, which requires the capability to add arbitrary propertysets to an object, which must NOT interfere with one another or the object's base properties. 2: If, in a dataskin-derived ZClass class definition, I define a "common instance" propertysheet, values in that propertysheet for instances get stored in the ZODB just like any other ZClass instances' propertysheets. Not exactly. What happens is that __getattr__ never gets called for those attributes, so you can't have a provider give a value for them. __setattr__ and __delattr__ *do* get called, so if you modify those values on an instance, the providers will get called. However, since they never get called for attribute retrieval, you will never see the effects of the change. In short, "common instance" property sheets are *broken* with respect to DataSkins and should be avoided in favor of DataSkin propertysheets which are built so as not to have this problem. However, if I define a "dataskin" propertysheet for my ZClass, I can provide the content of these sheets to my ZClass instances using AttributeProviders. Yes. However, because of the way Attributes work, I cannot supply data for a dataskin-propertysheet as a separate independent sheet object. The sheet comes from the ZClass, the data comes from an Attribute Provider. Yep. To supply an independent sheet object, you need a sheet provider. And ZPatterns "out of the box" only includes a Persistent Sheet Provider, primarily to support WebDAV's requirement for adding arbitrary property sets. 3: If I want to use a SheetProvider, and thus use some of the important features of ZPatterns, I need to use object.propertysheets.manage_addPropertySheet() on each ZClass instance that should have a sheet from a SheetProvider. One way of doing this is with a Trigger. Yes. Another way is that if you write your own SheetProvider, you can define its _objectAdding() and _objectDeleting() methods to automatically create the sheet. Or, if existence of the sheet is predicated upon something else, you can simply answer the getSheet/getSheets() method calls by checking to see if that sheet exists, and if so, returning it. This is useful when, for example, you need to provide an object with a propertysheet that presents and/or updates data from a legacy database or other external system. 4: If you needed to add this atop a class which needed to be "final" (in the Java sense, i.e. no modifications allowed), then the best route would be a custom SQL sheet provider. ..because the SQL sheet provider can provide sheets to ZClass-dataskin instances, even though the original ZClass was not defined to have this propertysheet. But I'd also have to add sheets to each applicablt instance, as in learning point 3 above. Right, unless you write your sheet provider to just provide the sheet anyway. Sheet providers get asked what sheets are available for an object, and can simply provide some whether they've been "added" or not. The "manage_addPropertySheet" step is optional if you're creating custom sheet providers which can either add the sheet automatically, or have the sheet just always exist. ___ 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] ZPatterns Question
Thanks for your answers, Phillip. Here's what I've learned. I still need to try these out on a test system, to prove to myself that they work the way I think they do. 1: ZClass instances can have PropertySheets added to them, independently of any sheets declared in the ZClass class definition. I've been working with Zope for a while, but this had never occurred to me. I guess this is just another one of those hangovers from writing in Java for so long. 2: If, in a dataskin-derived ZClass class definition, I define a "common instance" propertysheet, values in that propertysheet for instances get stored in the ZODB just like any other ZClass instances' propertysheets. However, if I define a "dataskin" propertysheet for my ZClass, I can provide the content of these sheets to my ZClass instances using AttributeProviders. (Are the above two paragraphs correct? Or can I use AttributeProviders to supply data for common instance propertysheets also, but I can't use default values for such sheets?) However, because of the way Attributes work, I cannot supply data for a dataskin-propertysheet as a separate independent sheet object. The sheet comes from the ZClass, the data comes from an Attribute Provider. 3: If I want to use a SheetProvider, and thus use some of the important features of ZPatterns, I need to use object.propertysheets.manage_addPropertySheet() on each ZClass instance that should have a sheet from a SheetProvider. One way of doing this is with a Trigger. 4: If you needed to add this atop a class which needed to be "final" (in the Java sense, i.e. no modifications allowed), then the best route would be a custom SQL sheet provider. ...because the SQL sheet provider can provide sheets to ZClass-dataskin instances, even though the original ZClass was not defined to have this propertysheet. But I'd also have to add sheets to each applicablt instance, as in learning point 3 above. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ 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 )
