October 2000 - Zope-Dev

Trying to catch up - what are the best Zope tools today?
by Itai Tavor 05 Oct '00

05 Oct '00

Hi, I've been out of the Zope world for a few months... now I'm back and I need to quickly write a small-scale e-commerce application. It's got enough peculiarities to make it impossible to do with eTailer or EMarket, so I'm trying to figure out the best tools and approach to use for writing it, but so much has changed in Zope since I last worked with it. There's ZPatterns, LoginManager instead of GenericUserFolder, new session management products... the new tools seem much better than the old, but most are in development and carry dire warnings, and at least some of the old tools don't work in Zope 2.2. Can anyone provide a quick rundown of the best choices for building a production site at this time? I'm going to need sessions, user registration and login, and the usual array of e-commerce pieces (products, carts, orders, payments...), with all data stored in SQL. I started reading about ZPatterns but I still can't get my head around it... I'm wondering if I should try to learn it fast enough for this project, or stick to what I already know. What in people's experience is the typical learning curve for ZPatterns? How much am I going to have to figure out to be able to build support for SQL storage? I couldn't find any examples for SQL use in ZPatterns - did I miss anything? Thanks in advance for any comments. -- Itai Tavor "Je sautille, donc je suis." C3Works itai(a)c3works.com - Kermit the Frog "If you haven't got your health, you haven't got anything"

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Re: [Zope-dev] Re: CoreSessionTracking proposal
by Anthony Baxter 04 Oct '00

04 Oct '00

>>> Toby Dickenson wrote > > Are you suggesting that the session token should actually > > store session > > data? > As an alternative SessionManager, it appears to have some advatanges that > others do not. It also has a major disadvantage, if you don't want the users to be able to monkey with their session settings. > Its also the only sensible option that lets you bookmark your place in a > session, and return to it much later (which interests me more). This of course assumes you put _everything_ in the session. This could become quite horribly Notes-like in it's URL. > Isnt the tree tag an example of one Session use case? It smells alot like a > session to me. Note that www.ekit.com's tree tag (go to, e.g. http://www.ekit.com/ekit/Info/) stores the tree tag state in the session. It was a simple enough mod to the tree tag (btw, in case no-one's repeated it recently, the tree tag is Pure Evil From Planet Ten, and must be destroyed :) Anthony -- Anthony Baxter <anthony(a)interlink.com.au> It's never too late to have a happy childhood.

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CORBA-ZODB: Is replacing global get_transaction() the only way...
by John D.Heintz 04 Oct '00

04 Oct '00

Hi all, I am about to embark on integrating ZODB with CORBA, and am in the deep thinking phase of the endeavor. ;-) What I want to do is _explicitly_ manage connections and transactions without being able to depend on what thread is running. I know that this is _not_ the way that Zope works, but if I want to use standard CORBA I think I have only two choices: 1) Explicitly associate Connections with Transactions in my CORBA layer. What I need to do is allow any thread to change a Persistent object from some Connection, and make sure that the right transaction is called for "register". 2) Build a complete wrapping adapter layer that does thread synchronization to the actual Persistent objects and proper thread for the transaction. - Lots of overhead and redundant coding - tricks with ExtensionClass might make this adaptation simpler to code, but still it won't be easy. Obviously number one is my preferred choice. In order to accomplish that, I see only two ways: 1) Modify ZODB to maintain a Connection to Transaction link, and modify cPersistence.c to use that link in the changed() function instead of relying on the standard get_transaction() thread index. 2) Replace the get_transaction() in globals to return the appropriate Transaction regardless of thread. Again, my preference is number one. After going over the ZODB code, I _think_ that a Connection is always associated with one Transaction. If this assumption is true, then it should be safe to make the change I'm proposing. If not, then I need to understand why so that I can rethink how to solve my problem. ;-) I hope that I've made my problems and ideas for solutions clear, if not please let me know. Also, I think that I should be able to make the changes to ZODB myself within the next few week, but only if there is the _possibility_ of folding them back into the main Zope codebase. Thanks for any help, John D. Heintz CORBA Threading description: CORBA defines the POA, which has two standard threading policies: ORB Controlled Model Single Threaded Model The POA is basically a controller for requests to one or more distributed objects, with thread policy as one of its parameters. The first threading policy means whatever the ORB gives you - single or multi, and you have to deal with all synchronizations. The second I consider a mis-nomer because there can be many threads, but only one at a time will access objects for a given POA. (This is the model that I perceive being used by default for ZODB object from a specific Connection.) -- John D. Heintz DataChannel, Inc. Senior Engineer 512-633-1198 jheintz(a)isogen.com ____________________________________________________________________ Get your own FREE, personal Netscape WebMail account today at http://home.netscape.com/webmail

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Zope 2.2.2 Issue: AttributeError: __call__
by knight 04 Oct '00

04 Oct '00

I hope I haven't overlooked anything here, and not posting ignorantly. After installing a fresh copy of Zope 2.2.2 on Python 1.5.2, everything seems to look ok. I created a new user with Manager, and then proceeded to create a subfolder for a new web site to test out some things in 2.2.2. I created some dtml documents, then I connected with ftp to create a few more dtml documents, and a couple subfolders with docs. All dtml docs in the main subfolder were renderable. ANY dtml docs in subfolders below that were _not_ renderable, and spit an AttributeError: __call__ generally inside the standard_html_header. However, thinking that there was something wrong rendering my header, I realized there was nothing technically wrong with the dtml in the header. After installing some products, they all ended up complaining about the same thing. I have confirmed this issue with the latest checkout of Zope2 from cvs. Can anyone else confirm this as an issue? Regards, Knight knight(a)phunc.com

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Zope Suitability for Computer Lab Project
by John Hopkins 04 Oct '00

04 Oct '00

Greetings from a "potential newbie". I need to build an application for recording clients who use a computer lab. The idea is to collect demographic information on clients who use the lab, and session information such as date/time and whether the client attended a class. Objects include clients, sessions and classes (or I think they do; I'm more used to thinking in relational terms. I was going to build it in MS-Access, since it's available on all the PC's in the lab, can do everything I need (including reporting), and I know it well; on the other hand, there are undeniable advantages to having something server-based with minimal client dependencies. I'm pretty sure it would take me more time to build it in Zope than in Access, mainly because I don't know Zope yet. What I don't know is whether this is an appropriate application for Zope; it's not really what I think of as "publishing"; more like data acquisition and subsequent reporting. Observations based on experience will be gratefully received. Thanks in advance, John Hopkins john_hopkins(a)bigfoot.com

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ConflictError
by Andre Schubert 04 Oct '00

04 Oct '00

Hi, who can tell me a story about the following error. thanks as 2000-10-04T15:49:35 INFO(0) Z2 CONFLICT Competing writes at, /Management/Geyer/Cluster_1/Verstaerker_1/Modem_7/chart_images Traceback (innermost last): File /usr/share/zope_2.2/Zope-2.2.0-src/lib/python/ZPublisher/Publish.py, line 175, in publish File /usr/share/zope_2.2/Zope-2.2.0-src/lib/python/Zope/__init__.py, line 235, in commit File /usr/share/zope_2.2/Zope-2.2.0-src/lib/python/ZODB/Transaction.py, line 251, in commit File /usr/share/zope_2.2/Zope-2.2.0-src/lib/python/ZODB/Connection.py, line 267, in commit ConflictError: yä

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ZPatterns: SkinScript discovery
by Steve Alexander 04 Oct '00

04 Oct '00

I just found out that you can access all sorts of useful methods in SkinScript from the magical "_" namespace variable. Let's say I have a DataSkin that has a propertysheet "journey", which has a "steps" property of type "lines". I can expose its "steps" property as an attribute, and also a neatly formatted version of the same, using this SkinScript: WITH self.propertysheets.get('journey') COMPUTE steps=getProperty('steps'), steps_comma_sep=_.string.join(self.steps, ', ') -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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DynPersist.so from ZPatterns 0-4-2a3
by Danny William Adair 04 Oct '00

04 Oct '00

Hi all! I'm desperately looking for the DynPersist shared library (new for ZPatterns 0-4-2a3) in compiled form. Can someone help me (send it to me)? I'm running a Zope instance at NIP (www.nipltd.net) that's 2.2.1 on Unix platform. tia, Prost, Danny

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How to add a SessionID to each page
by Loibl Johann 04 Oct '00

04 Oct '00

Hi, I would like to add a SessionID at the end of each requested URL because I would like to know which pages were requested by one user in one session. For example like AMAZON does it: www.amazon.com/books?SessionID=123456 <http://www.amazon.com/books?SessionID=123456> My problem: There are to many pages belonging to my homepage that I can't rewrite each link like: <a href="next_page?SessionID=<dtml-var SessionID>">next_page</a> Also I tried to pass a SessionID with the help of SiteAccess but a automatic insertion of a random ID doesn't work at my machine. Could anyone give me please a helping hand? (Also, excuse my English) Thanks, Hannes

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Re: [Zope-dev] (no subject)
by Dieter Maurer 04 Oct '00

04 Oct '00

ralf.herold(a)charite.de writes: > using LocalFS 0.95 war fine until trying to upgrade to Zope 2.2.2. Both > freshly installed, the following snippet raises the error: "Unauthorized", > "You are not authorized to access read.": > > <dtml-var standard_html_header> > <dtml-var "frei['analog.html'].read()"> > <dtml-var standard_html_footer> In earlier Zope versions, a method without a permission meant "can be used freely". Now, it means "cannot be used via DTML/URL". Thus, you must provide a permission for "read". Unfortunately, "read" is not a method of "LocalFS" but from the Zope objects wrapped around the files. You, probably, will not want to change the respective Zope sources. The quickest solution for you would be an external method that gets the file, performs the "read" and returns the result. Alternatively, you may subclass the Zope object classes, provide a permission for "read" and use them in "LocalFS._create_XXXX". Dieter

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