March 2001 - Zope - Zope lists

IE caching issues
by kosh 19 Mar '01

19 Mar '01

Not sure if this is a zope issue or not. I have some people doing work on a site developed in zope however ie is often showing the wrong version of the page. I followed the caching instructions in http://www.zope.org/Members/htrd/howto/caching and it works on every browser except ie. I have checked and they have set the browser to check on every page view however often it does not even hit the webserver. I have had them hit reload while watching server logs and no connect was attempted. I then tried it in vmware using nt 4 with ie 5.5 and it does the same thing also. Even when the cache is deleted on ie and it is told to run with no cache it seems to cache the documents somehow. It seems the only solution is rebooting windows on their machine which is not a good one or using some version of netscape. If someone knows why this is happening I would really like to get it solved. If I could get away with having no ie support I would but alas that is not an option I have. :(

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Loginmanager questions
by Alex Verstraeten 19 Mar '01

19 Mar '01

for those who have tried loginmanager: I've been trying to install and use loginmanager but it seems too complicated and undocumented (zope 2.3.0, python 1.5.2) I've followed some SQL/LoginManager howto without success, but before trying to get this working, I'd like to know some more about login manager if I do select a folder : security: add role , will that role get added to the loginmanager user source or do I have to map roles manually? can I add users, change passwords, etc, the way I currently do ? (select acl_users folder, click "add" or "delete" button, select a user, and change its password, etc) I mean, can a acl_users folder with loginmanager act the same way it does now (except that will authenticate with a form, and storing users on a SQL) please let me know if you know any documentation other than reading the loginmanager source code (which is not my idea at all) Thanks Alex

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Using psycopg connections directly
by cg＠cdegroot.com 19 Mar '01

19 Mar '01

Hi, I have an O/R mapping thingy that's written outside of Zope. Because I want to make it a good citizen when it is called by e.g. a Zope product, I've extended it to use Z Database connections; more specifically, it assumes psycopg (metadata intepretation under Python is quite driver dependent, it seems...). Because psycopg is advertised as having a per-cursor commits, initially I just did the same thing in my code as a Z SQL Method would do: call the database object for a connection and run query() on it. However, it turned out that when multiple threads did this, one thread's commit would also commit work on another thread. This is probably due to the fact that the psycopg DB class commits on the connection, not on the cursor it used. So I now grab a cursor, and register that (inside a wrapper) with the transaction manager, for every query. The finish/abort code does a commit/rollback and then a cursor.close() (shortly after that, the GC destroys the cursor). However, I seem to be leaking connections, because the number of in-use connections quickly goes up and Postgres starts complaining. There's probably some interaction between what I do and psycopg that I don't understand. Would anyone have a suggestion as to how I could use psycopg Z Database connections from Python code in such a way that everything works smoothly? What's the Zope model anyway - does it instantiate one Z connection per thread or do all the threads use the same connection and should the connection figure it out by itself? -- Cees de Groot http://www.cdegroot.com <cg(a)cdegroot.com> GnuPG 1024D/E0989E8B 0016 F679 F38D 5946 4ECD 1986 F303 937F E098 9E8B

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Zope not updating Control_Panel/Products?
by cg＠cdegroot.com 19 Mar '01

19 Mar '01

Hi, I have a problem with a Zope-2.3.0 installation (running with ZEO): when I add products to the Products/ directory, Zope does initialize them, but they are not added to Control_Panel/Products and therefore you cannot create new instances of the classes contained in the products. Zope starts normally, I've tried removing the ZEO caches, restarting both nodes, to no avail. It happened before and that's why I upgraded from 2.2 to 2.3, which seemed to help, but now it's back to the old behavior. The development system had 2.2 and now has 2.3 without ZEO, and works like a charm; it's just the production system that has these problems (so I can tell you that the problems are not in the products: they initialize without exceptions and they are copies of products as they are installed on the development system). Anyone familiar with this problem? Cees -- Cees de Groot http://www.cdegroot.com <cg(a)cdegroot.com> GnuPG 1024D/E0989E8B 0016 F679 F38D 5946 4ECD 1986 F303 937F E098 9E8B

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RV: [Long] Development in Zope (Was: Re: [Zope] data point on ease of learning Zope -- I give up.)
by Ernesto Revilla 19 Mar '01

19 Mar '01

Hi Cees, hi Stefano, I have the very same problem. I think we would enjoy an IDE like VisualStudio or Delphi for development and deploy the results under Zope. Still this is not the case. A tighter union between ActiveState and DigiCool could give such results. ActiveState has the IDE and DigiCool has the Application Server. I still haven't seen the Komodo or the Wing packeges working. Also, the documentation for developers (say the class/package model and the function-call interfaces and semantics) is scarce, but I've read that this is now in development. This should be directly accesible by an IDE or a Documentation browser with search capabilities and so on. Of course, could be Zope, but Zope is not an IDE, and I need the docs accesible from the window where I write my source code. I can identify some more features I'm would enjoy in a development framework: * A data modeller, object oriented, with adaptors to real-world storage systems. UML-modelling would nice. I know that some of these exist but I still didn't see one working. I would like to model my (persistent) classes visually, designing the inheritance relations and the properties a class has. Also I would put modification info, such as: if attribute x of class instance y changes, change also attribute z of class instance w. This data schema would be translated to a OODMBS with some updating logic or into a RDBMS with all the referential integerity rules and triggers to maintain data cosistent. * A document-framework. This is a good way to abstract all type of real-world logic. The document framework would make it possible to search and recover document, and to update one or more class instances in one transaction, and treat any multiuser access problems. * A GUI-builder, which could work in a generic way, having some types of widgets and wich could help to build the GUI graphically. I saw this is VisualAge for Java and I liked it very much. But now, there should be local calls and remote procedure call based e.g. on XML-RPC. The interfaces could translate to Java, HTML/JavaScript and other languages. It would be like a visual modeller for the Mozilla framework which separates contents (what elements will be on the screen), behaviour (what action will perform whatever event), locales and layout (where will be put each of the elements, what colour, etc.). This should be completed with guidelines for designing GUI and integrate them with the business logic (and a document framework) running on the application server. All these ideas come from the wishes to get a higher level of abstraction. We need persistent classes, we need a data-modeller and we need a way to change data schemas in a fast and flexible manner. Also do we need to separate data-model aspects from representation on the screen, so we can make good projects dividing software departments into backend and frontend engineers (and possible these into programmers and visual designers). But frontend and backend are very related and so backend engineers should have an easy way to write documentation for the classes and their methods, and frontend engineer should have an easy way to access the necessary documentation. The power of the GUI will directly affect the successfullness of the software. It's the same as the use of natural language: If it has a lot of words which effectively describe the concepts I need (in an easy way) and I use them in the right manner, communication with other people will be very effective and efficient, the degree of communication is one of the most important factors of business success. I have a ERP solution (made with MS-Access) for small companies and want to migrate to another platform, but I don't know how to start. I would like to use standard browser technologies, but sometimes it seems not to be sufficient. Also I would like to have a O(bject)Q(uery)L(anguage) Object Store to access efficiently thousand of objects, but I still haven't found / experienced a good solution. The same thing with the data-modeller and document-framework. So I spend really a lot of time browsing through the Web. What should we do? Erny > Hello Cees > > the problem you raised is exactly the same problem I am facing. Allow me to > list my problems: > > - I am an experienced Java programmer, as well as many other -win- languages > - I want to build a big site with lots of logic > - I want to have a comfortable tool > - I do not want to build tons of classes from scratch. > > I have been evaluating a lot of other solutions, including ColdFusion, > Enhydra as app servers, PHP, ASP, and other as languages. After a lot of > headaches, I came out with the idea that unfortunately there are no "all in > one out of the box" solutions. From product A you get abc tools/solutions, > from B you get def and so on. So at the end I decided to stick with Zope, > for many reasons including: > > - Perl, maybe IMHO not the best, but terribly efficient and widespread. > - Python, even if I do not like it at all, but after all the important is > that it does it work :)) > - XML-RPC so Java for me > - you can hide Zope behind Apache, so you can also use Tomcat, PHP and > whatever. > > In the end, a mig mix. But please tell me, where in world can you find an > all in one? I did not, so at least, I will take the advantage of the great > manageabilty of Zope, those tons of "speed-of-light" tools like DTML-IN and > ZSQL methods, and do the rest in the tool I like most for that specific > work. > > I do not like it, however, because it lacks consistency, but at least I will > not end up reinventing the weel that somebody has already invented, and > debugged veeeery well, seen the tons of peple using Zope. > > Regards > Stefano >

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ZOPE installation problems
by K H Subrahmanyan 19 Mar '01

19 Mar '01

Hi, I tried to install zope on a Linux (slackware) platform. but it is not installing. I have successfully installed zope in Redhat. what may be the problem. subrahmanyan.

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Wish List
by Ernesto Revilla 19 Mar '01

19 Mar '01

Hi all, some wishes: 1. integrate Zope Beans or something like this into the core. They are cool. 2. Java-applet to design UML diagrams (doesn't need to be complete, but should model class charts, with the possibility to transform the diagrams into Zope Beans. 3. make ZODB understand OQL. (Bombastic for translating relational systems into OO systems, great for prototyping). Cheers, Erny

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Design Patterns
by Ben Ocean 18 Mar '01

18 Mar '01

Hi; I'm new to Zope and Design Patterns, but I notice some wonderful similarities between the two. Can someone please help me to understand which design patterns Zope has laid into its architecture and where? The reason for my question is specifically because of the *Factory* method. Is this a straight *Factory Method* as outlined in the GoF book, or is it an *Abstract Factory*? Are Abstract Factories built into Zope's architecture? How about other creational methods, such as Prototype and Builder? How about Behavioral Methods and Structural Methods? TIA, BenO

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Re: [Zope] Acquisition
by Dieter Maurer 18 Mar '01

18 Mar '01

Axel Missbach writes: > ... unexpected acquisition behaviour ... > Where is my failure? > Is there another (better) way to do it? Jim Fulton gave a talk about Acquisition algebra at a conference. He explains the primary acquisition behaviour by the key sentence: "Containment before Context". Either look at this talk on zope.org or read the acquisition section in URL:http://www.dieter.handshake.de/pyprojects/zope/book/chap3.html Dieter

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Re: [Zope] Upgrading 2.0 to 2.3
by Dieter Maurer 18 Mar '01

18 Mar '01

Albert Kinderman writes: > I have a site running on 2.0.1. I would like to upgrade to 2.3.x. The big step is to 2.2 because with this step Zope security model changed. There is a document from Brian explaining what need to be change (-> Zope Security on zope.org) The step from 2.2 to 2.3 will not make big problem. You plan to go directly to 2.3. Nevertheless, you need to take care of the changes introduced with Zope 2.2. Dieter

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