April 2002 - Zope - Zope lists

Audio visualisation problem
by sjoerd siebinga 03 Apr '02

03 Apr '02

Hi all. I am a newbie at python and zope. And this is what I want to do. I want to create an web-based audio transciber that displays wave-forms and spectograms using the snack toolkit ( http://www.speech.kth.se/snack ). At this moment I have most things working on my desktop using tkinter. A short sample script is included below. Is there any way to port such a script to zope? thanks in advance. sjoerd ======= #! /usr/bin/env python from Tkinter import * from tkSnack import * root = Tkinter.Tk() initializeSnack(root) s = Sound(load='ex1.wav') c = SnackCanvas(height=100, width=400) c.pack() c.create_waveform(0, 0, sound=s, width=400) Button(root, text='Exit', command=root.quit).pack() root.mainloop() ===========

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Ri:Z-SQL Method performance
by Stefano Vedovelli 03 Apr '02

03 Apr '02

Hello Rudi >My problem is the perfomance when executing a Z SQL Method >selecting a huge number of records, like 'select nr, name, ... from <table> >where ...'. dependend on the where-specification i have to deal with sets >about =~ 10000. when a ZSQL method is executed, the reult is fetched into a list object. If your query returns a great amount of records, the process of loading the list can take long. >my mysql-client tells me, that mysql by itself takes about .02 to .04 secs to >perform The MySQL client does not fetch all rows at once; rather, it retrieves the correct number of rows depending on your screen. >And: when i test a query in the Z SQL Method test-tab, i get 50 results per >page, with the same speed-delay. but when i click on the <next 50 ...> link, i >get instantly the next 50 records displayed. How is this perfomed and how can The fact that the next 50 elements are displayed so fast, is that because either Zope and MySQL perform a little caching. If you wait long enough, you will see that the display will take more. Let me advice you, however, that having a query that returns 10000 rows in a web application is bad practice or bad design. This is because you can potentially have thousands users requesting the same page, thus running the same query over and over on the database, potentially causing a loss of performance and can create a big swapping activity, especially if the record is big. It is true that sql servers cache and manage results, but this is still not a good excuse to allow a potentially high number of users to run such am heavy query. You should consider to break it up. And redesign properly. Do you like to flip through thousands of pages to reach the record you want? :) Hope this helps Stefano Message: 6 From: Rudi Wurm <net_seeker(a)web.de> To: zope(a)zope.org Date: Tue, 2 Apr 2002 20:15:42 +0200 Subject: [Zope] Z-SQL Method performance my situation: Zope 2.4.2 (binary release, python 2.1, linux2-x86) ZMySQLda 2.0.8, MySQLdb Revision 1.11 My problem is the perfomance when executing a Z SQL Method selecting a huge number of records, like 'select nr, name, ... from <table> where ...'. dependend on the where-specification i have to deal with sets about =~ 10000. my mysql-client tells me, that mysql by itself takes about .02 to .04 secs to perform the query, when enterd by hand into the mysql-client. a small python-program using routines from the _mysql-module doesnt take much longer. But telling a dtml-method to use the Z-SQL-Method in an <dtml-in <name of z-sql-method>> statement, it takes about 4-5 seconds, and thats very long. Does one know how to speed it up or how to tune a z-sql-method, and whats the reason for the delay ? And: when i test a query in the Z SQL Method test-tab, i get 50 results per page, with the same speed-delay. but when i click on the <next 50 ...> link, i get instantly the next 50 records displayed. How is this perfomed and how can i achieve this in batch-processing via <dtml-in start=?? ...> ? The batch-approach i use looks like <dtml-in expr="sql-query(REQUEST)" size=10 start=query_start> <dtml-if sequence-start> <dtml-if previous-sequence> <a href="<dtml-var URL><dtml-var sequence-query>query_start=<dtml-var previous-sequence-start-number>"</a> </dtml-if> </dtml-if> (my display of data) <dtml-if sequence-end> <dtml-if next-sequence> <a href="<dtml-var URL><dtml-var sequence-query >query_start=<dtml-var next-sequence-start-number>"></a> </dtml-if> </dtml-if> </dtml-in> , its like the example from the zope-book, batch processing with in-tag, chapter 8. activating caching for the Z SQL method helps not, because when i use it it returns allways the old set of data although the variables specifying the where-clause have changed, when a new query is send. thanks in advance Rudi free people, free living, free software

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webdav: collection does not work when I use file type object as baseclass
by Robert Rottermann 03 Apr '02

03 Apr '02

Hi there, I am creating a product that has a folderish and a file type aspect. I therefore use both ObjectManager and DTMLMethod as its base classes. When I do that, I can not use Webdav to access folders which contains instances of my product anymore. If I get rid of the DTMLMethod as base class things work fine again. Is such a combination of base classes sensible? If yes, what must I do to have webdav working? thanks for your help. Robert www.redcor.ch

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Zope 1, Lotus Notes 0, M$ .5
by Richard Gordon 03 Apr '02

03 Apr '02

Geek Summary: Thru some bizarre alignment of the planets, a large international client of mine has rejected a proposal to migrate it's web-based ISO documentation to Lotus Notes in favor of my Zope alternative even tho a month ago the only option in the running was Notes and none of the people who matter had ever heard of Zope. The current implementation consists of a large number of M$ Office documents being served via NT/IIS4 and maintained with a lot of Python. The forthcoming version will still be mostly Office documents (please don't point out the obvious- there are some good reasons for this) served by windoze2k/Apache, but augmented by Zope and MySQL for managerial and other purposes. But it gets stranger: This good fortune is largely attributable to Evil Bill and the passions that M$ arouses. It seems that at the corporate level, there was a tussle about whether a proposed enterprise resource portal would be based on Lotus Notes or on M$ SharePoint- this is still in the "great idea" stage and goes well beyond the scope of the ISO documentation intranet site. Since my scheme has most of the content remaining in the file system, I was able to tell them that it was obviously consistent with a SharePoint portal that could otherwise be ignored, while it was by no means clear that the Notes solution would allow for this because of some security constraints that never made much sense anyway. The Point: I am recounting this episode to give some encouragement to those many of you who daily fend off suggestions that whatever you are doing would be a lot better if you would just use some proprietary piece of crap in lieu of Zope. Occasionally, you don't have to sell Zope so much as make sure that the factions in favor of other approaches exhaust themselves fighting with one another, so you win by default (especially if you can claim to be M$ tolerant to boot). Given the context and history of this situation, it's also further proof that Chaos Theory is not just theory. So now I know that there will be ample Guinness on the table for many months to come and I have Zope, Python, and the wonders of corporate politics to thank for it. Richard Gordon -------------------- Gordon Design Web Design/Database Development http://www.richardgordon.net

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Re: Solaris threading, redux
by Anthony Baxter 03 Apr '02

03 Apr '02

>>> Anthony Baxter wrote > from http://www.theregister.co.uk/content/4/24658.html > > One of the important changes in Solaris 9 is a > change in the threading library. Solaris 8 had an more on this can be found at: http://java.sun.com/docs/hotspot/threads/threads.html -- Anthony Baxter <anthony(a)interlink.com.au> It's never too late to have a happy childhood.

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Solaris threading, redux
by Anthony Baxter 03 Apr '02

03 Apr '02

from http://www.theregister.co.uk/content/4/24658.html One of the important changes in Solaris 9 is a change in the threading library. Solaris 8 had an alternate threading library that Sun was allowing customers to play around with, and this is now the default threading library with Solaris 9. The replaced threading library will not affect application compatibility - Solaris 8 apps will run unchanged - but this change in threading schemes will allow nearly all applications to scale to larger processor counts than they currently can on Solaris 8 servers. (This is known as vertical scaling in the nomenclature of the server business.) no idea what this will do for Zope... -- Anthony Baxter <anthony(a)interlink.com.au> It's never too late to have a happy childhood.

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zope license plate (trivial non-technical question)
by Donald Braman 03 Apr '02

03 Apr '02

I saw a van with a license plate that said "ZOPE" in Los Angeles...anyone know who it was? -Don

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How to refer an object in a sub folder?
by Rengasamy, Samy 03 Apr '02

03 Apr '02

How to refer an object in a sub folder? I have a folder 'java' under a folder 'tech'. I have a template 'index' in 'tech'. How do I refer to 'index' in the folder 'java' from an object in 'tech'? <dtml-var java/index> ??? Thanks in advance, Samy Rengasamy.

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Allowing access to Zope Product in Control Panel
by Itai Tavor 02 Apr '02

02 Apr '02

Hi, I have a python Product MyProduct, defining a class MyClass. I want to be able to do two things with this class from a Python Script: - Access a property defined in the class without creating an instance of the class class MyClass(SimpleItem): menu = ('a', 'b', 'c') In Python Script: menu = context.Control_Panel.MyProduct.MyClass.MyClass.menu - Create an instance of MyClass without doing registerClass on it. The question is, how do I create the right permissions so the above can be done? I tried playing with the various methods detailed in PythonScripts/module_access_examples.py but didn't get anywhere. TIA, Itai -- -- Itai Tavor -- "Je sautille, donc je suis." -- itai(a)optusnet.com.au -- - Kermit the Frog -- -- -- -- "If you haven't got your health, you haven't got anything" --

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tar xvf Zope-2.4.x-to-2.4.1-src.tgz doesn't work
by Alex.Basile＠bmsus.com 02 Apr '02

02 Apr '02

Hi, I've tried serveral times on a Sun0S box but keep getting the following error message: tar: directory checksum error. Any ideas? Thanks, Alex

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