September 1999 - Zope-Dev

DTML Document ZClass storing id as <string>
by Jason Spisak 09 Sep '99

09 Sep '99

This is a second post on this one. I have a ZClass based on DTML Document that is doing something weird. After I create an instance, I can see it in the management interface and it has the 'id' that I gave it. However, I can't bring it's id up using , or the tree tag, or . I get back <string>. I can create these objects from python just fine. Here is the DTML used to create them:          The id 'html_resume' comes up in the management interface, but I can't get a link to it otherwise, or it's id back. Any ideas? -- Jason Spisak webmaster(a)mtear.com

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Intersection (set) in Zope
by Jason Spisak 09 Sep '99

09 Sep '99

Does anyone know if Zope already has (I'll bet it does, it's just a matter of finding it, which I haven't yet) an object or method for intersection or set of two lists. I want items common to both lists. It's a simple python external method, but why write code t hat's already written. I combed the dtml guide and the source in places and can't see what it would be called. Any ideas? Jason Spisak webmaster(a)mtear.com

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ZClass based on DTML Document not getting 'id'
by Jason Spisak 09 Sep '99

09 Sep '99

Gang, I have a ZClass based on DTMLMethod and when I instanciate it, the id shows up in the management interface, but if I do  inside it, I get <string>. Help? Jason Spisak webmaster(a)mtear.com

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RE: [Zope] Re: [Zope-dev] Re: [Zope] Import from Zope-1 to Zope-2
by Michel Pelletier 09 Sep '99

09 Sep '99

> -----Original Message----- > From: Michael Bernstein [mailto:mbernstein@profitscape.net] > Sent: Thursday, September 09, 1999 12:42 PM > To: Michel Pelletier > Cc: zope-dev(a)zope.org; zope(a)zope.org > Subject: [Zope] Re: [Zope-dev] Re: [Zope] Import from Zope-1 to Zope-2 > > > Michel Pelletier wrote: > > > <dtml-with "_.Client.Object('http://A/YourDocument')"> > > <dtml-var id> > > </dtml-with> > > > > and print 'YourDocument'. You can pass autentication > information in to > > all of the calls to access restricted object. > > Excelent! Content and sevice syndication among Zope sites > without going through > RSS or XML-RPC! This will start a snowballing of Zopes > 'network effect' and > increase the value of belonging to the Zope 'network'. Woah! Further experimentation shows that it is not this simple, but close. There would have to be some pretty nifty abstraction code above Client to do what you want, Client isn't much more powerful than XML-RPC, if at all, it's just more Zopeish. > In fact, unless I misunderstand, this will allow Zope > applications to not only > expose services to other servers, but will allow truly > distributed applications... Yep. Note that the performance won't be all that (because it's HTTP). This also doesn't really solve the problem of transparent database replication. > Will there be a separate set of permissions to allow/deny > objects to be called > like this? No. 'Client' waddles, swims, and quacks just like a 'web browser' to Zope. If a method or object is protected by a certain permission, then the 'Client' call must supply a username and password that matches a user with a valid Role that can satisfy that permission. Just like a browser. If the server supplies a cookie, 'Client' will return it with the rest of the HTTP headers and you can store it seperatly (since 'Client' calls are stateless). > > Another no-no would be for an object to call Client on itself. I > > suspect this would cause some sort of StackOverflow > exception. I'm not > > sure how well Zope would take that kind of behavior. > > Hmm, what if you have Zope behind Apache running two or more > virtual domain names? > can they call each other using this method? As long as there is a 'stop' you can do this like any other recursive operation. By no-no I didn't mean you shouldn't do it, I meant you should be aware that it is recursive. -Michel

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Re: [Zope] Import from Zope-1 to Zope-2
by Michel Pelletier 09 Sep '99

09 Sep '99

"Jay, Dylan" wrote: > > > -----Original Message----- > > From: anders.brun(a)abc.se [mailto:anders.brun@abc.se] > > Sent: Tuesday, September 07, 1999 05:24 > > To: zope(a)zope.org > > Subject: [Zope] Import from Zope-1 to Zope-2 > > > > > > Hi, > > > > I have a site built in Zope version 1.10.2 (binary release, > > python 1.5.1, linux2-x86). Now I´d like to export everything > > into Zope-2. It doesn´t work using export/import ... Have > > anyone experiensed anything similar? > > The answer is to use the upgrade utility in the utilities dir but on a > related note heres another idea I had. How about a product that can mount > one zope ODB into another. Using XML-RPC or something to connect the two > sites togeather over the internet. It may not be fast enough for using that > way but at least it would be really easy for transfering data between zope > odb's. We are entertaining the possibility of putting ZPublisher.Client into the _ DTML Namespace. I am primarily championing the idea. 'Client' offers many cool uses. 'Client.Function' will call a remote 'Zope Method' which marshals simple types around (int, list, tuple etc.) and act as Zope oriented RPC. 'Client.call' is a convienent wrapper around 'Client.Function'. These both have the upshot of working with any URL, turning non 'object content' into file Message objects and return them in a list. Even cooler, 'Client.Object' will create surrogate objects of remote Zope objects. If you have a DTML Document on machine A, then Machine B could say: <dtml-with "_.Client.Object('http://A/YourDocument')"> <dtml-var id> </dtml-with> and print 'YourDocument'. You can pass autentication information in to all of the calls to access restricted object. The downside is that this is the first method to be introduced into DTML namespace that may block forever (not so say that in the past other methods didn't block because of bugs ;). The reason why there are no blocking methods is because Zope used to be single threaded. If the above Client calls took a minute to return, then your entire system hung for a minute. Granted, the OS should eventually time out the socket. Now that Zope is multi threaded, this isn't much of an issue, but it should be understood that these calls block and will take time and maybe hang individual threads for a while. Another no-no would be for an object to call Client on itself. I suspect this would cause some sort of StackOverflow exception. I'm not sure how well Zope would take that kind of behavior. The proposal mearly needs to pass the scrutiny of our security dictator. It is a trivial change to the code. I think it's pretty safe since no holes are introduced in the server, just client functionality, and any security bugs this could reveal could be just as easily exploited in python with Client or urllib (immagine, hacking machines in DTML!! It *is* a real language ;). -Michel

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RE: [Zope] Re: Two newbie questions + Zope patch
by Michel Pelletier 09 Sep '99

09 Sep '99

> -----Original Message----- > From: Evan Simpson [mailto:evan@tokenexchange.com] > Sent: Thursday, September 09, 1999 9:39 AM > To: Michel Pelletier; Martijn Pieters > Cc: zope-dev(a)zope.org; zope(a)zope.org > > <dtml-var number/3/the_larch> Ok. > <dtml-with thingy><dtml-var "_[varwithstringpath]"></dtml-with> That's cool. > <dtml-var "_.getattr(eric(), 'half/a/bee')"> Ouch! I can see changing var to work with relative paths, but not getattr. You can try and convince me otherwise but I think _.getattr should work as much like the python getattr as possible (after all, it *is* the python getattr!). -Michel

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Use Factories
by Jason Spisak 09 Sep '99

09 Sep '99

Zopists, I discovered a mapping that probably was meant to be turned on by default like the Add Permission, when you create a ZClass. Inside the Factory that is created by default when you adda ZClass, go under the define permissions tab. You have to map the "Use Factories" permission to the permission you want to apply to using that factory. It isn't enough just to map the "Permission" on the edit tab of the Factory to the "Add MyZClass" permission, you have to duplicate that under the "Define Permissions" tab. Unless you want only people with the Manager role to add those, then the default works. Just a heads up. Jason Spisak webmaster(a)mtear.com

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Re: [Zope] Re: Two newbie questions + Zope patch
by Michel Pelletier 09 Sep '99

09 Sep '99

Michel Pelletier wrote: > I'm not sure what your getting at here, but if you want to resolve a > path to a URL try: > > <dtml-with "REQUEST.resolve_url((SCRIPT_NAME + '/path/to/object'))"> > blah > </dtml-with> > Before I shot my mouth off, I should have metioned that this ability comes with a catch. This sort of functionality was necesary for ZCatalog and WebDAV to resolve URLs into Zope objects, but the usage and semantics of path=object-traversal were never standardized. In addition, the solution to serve the needs of the application did not, unfortuatly, jive with ZopeFind and ZCatalog. Brian and I had a hard time expaining the nature of the problem at the team meeting today, so I hope this explains it to everybody. ZopeFind is a method that will start at a container and search for objects that meet certain criteria with the option to recursivly traverse subfolders. Anyone who has used the Find view in the managment interface will be familiar with this, the interface is just an input form to the ZopeFind method that does all the actual work. Zope find returns a list of (relative_path, unwrapped_object) pairs. The relative_path, is *relative to the container from which ZopeFind was executed in the context of*. 'unwrapped_object' is the acutal object, not including any acquisition wrappers, therefore 'object.absolute_url()' just returns the id of the object, because there is are no layers of acquisition wrappers to build the path from. This is not a problem in itself, the absolute url of the object can be built by '(URL1 + relative_path). A further complication however is added because of the way ZCatalog remembers objects. The ZCatalog.Catalog.Catalog class works on the basis of object and their unique identifiers. The unique identifier can be anything at all, it is just used a document id in the class inverted file index that ZCatalog.Catalog.Catalog uses. The ZCatalog.ZCatalog.ZCatalog class, which is the actual Zope objects, used a (jeez) ZCatalog.Catalog.Catalog object as its engine, what it uses as a 'unique identifier' is the absolute *path* of the object, which is identical to the absolute url without SCRIPT_NAME (ie http://machine:port) in front of it; like '/absolute/path/to/object'. It would make no sense to catalog the whole URL, because if you changed the name of the computer or moved the port, your catalogs would break. 'REQUEST.resolve_url(URL)' wants an absolute url beginning with http: (like absolute_url() is supposed to return). ZopeFind returns relative paths with no context, and ZCatalog wants absolute paths. The work arounds between these three systems are simple, but the problem is that there are three seperate APIs in Zope that work with URLs in different ways. Brian and I tackled this problem in ZCatalog immediatly before the final release. The problem was discovered when a bug was reported that ZCatalog did not return proper URLs of objects when the Catalog was not in the root folder. The solution was simple, use absolute URLs everywhere and strip SCRIPT_NAME off of URLs before cataloging them, and with friendly community support, we found this discrepancy. So until we work it out by coming up with a common standard and implimenting it in the 2.1 release, use REQUEST.resolve_url(), ZopeFind and the Catalog with caution. When you absolutly must do it, use it like ZCatalog does and make sure you pass it the resolve_url() the absolute_url() of a properly wrapped object, or that you prepend URL1 to a relative path, and strip SCRIPT_NAME from URLs before calling Catalog methods. -Michel > -Michel

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Can't get ZClass baseclass to behave as DTML Method
by Martijn Faassen 09 Sep '99

09 Sep '99

Hi there again, Python and DTML Methods, one way or another they seem to be the theme for me today.. A couple of weeks ago I asked the same question (I encountered it in different circumstances). I'm trying to create a ZClass (deriving from a Python base class) that behaves like a DTML _method_. To this purpose, I tried to define this __call__: def __call__(self, client, REQUEST=None): "Call this ZClass as a DTML method." return self.render(client, REQUEST) in the base class that is inherited by a ZClass. If I grok the answers I got today by Martijn Pieters and Evan Simpson right, the arguments mean the following: self - the instance of this ZClass client - the object we're calling this method on (in my case an XML node) REQUEST - the regular request object the 'render' function figures out how to display the node (client) and returns the resulting string. This is however not working -- if I call an instance 'foo' like this on an XML node, like this: xmldoc/e7/e14/foo instead it'll display index_html (that is acquired and not defined on the ZClass). It apparently isn't calling __call__ at all. How do I fix that? Do I have to go full fledged product to do this? I'd like to use ZClasses because it's easier, but perhaps they simply don't allow it? Once I get this working I'll go back to the calling DTML Methods from Python problem again. :) Regards, Martijn

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Multiple inheritance woes
by Martijn Pieters 09 Sep '99

09 Sep '99

Hmm.. I know this is a python question, but DejaNews nor the Python website give me the answers I am looking for: I define a baseclass derived from CatalogAware and DTMLMethod: class Base(CatalogAware, DTMLMethod): def index_object(self): # check a few things I want to know about # before indexing, maybe even not allowing # the indexing CatalogAware.index_object(self) Then I define a bunch of classes based on this base class: class A(Base): pass class B(Base): pass etc. Now, if I do the following: a=A() a.index_object() I get a TypeError: unbound method must be called with class instance 1st argument Now, I have seen all sorts of messages relating this error, but none of them seem to relate to my problem... self in Vase.index_object _is_ a class instance, a step-by-step debug proves this. The python interpreter just won't accept it =(. -- Martijn Pieters, Web Developer | Antraciet http://www.antraciet.nl | Tel: +31-35-7502100 Fax: +31-35-7502111 | mailto:mj@antraciet.nl http://www.antraciet.nl/~mj | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 ------------------------------------------

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