March 1999 - Zope-Dev

RE: [Zope-dev] New Counter Product
by Paul Everitt 25 Mar '99

25 Mar '99

Martijn wrote: > That would be something for a new Event structure in Zope. I > think there > are already too many different notification calls... Correct on both counts. > A Event handling mixin would be nice... you know, registering > which Events > are available on a given object, registering of event > listeners, standards > towards canceling events.... Are there any ideas/plans on this DC? Yes, this had been discussed back in the Bobo/Principia days but nothing ever came of it. --Paul

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RE: [Zope-dev] New Counter Product
by Paul Everitt 25 Mar '99

25 Mar '99

Michel wrote: > Howard wrote: > > 1. How can I create a variable within a Product that will not be > > persistent (i.e. will not be written to disk)? > > > Prefix your variable name with _v_. If you don't want the > attribute foo > to be persistent, call it _v_foo. But alas, there's a dark side to this. If you're object gets swapped out by the Zope cache manager, splat, there goes the updates since your last change. Presumably it wouldn't be as it would be getting used a lot. There is a way to make your objects "sticky", i.e. they won't be deactivated. But Jim isn't comfortable documenting it. Sticky appears to be the operative term here... --Paul

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New Counter Product
by Shaw, Howard 25 Mar '99

25 Mar '99

Well, it is basically finished and working, combining a visible Product interface and a counter tag... But, overriding __setstate__, removing the temporary entry from the state, and called Persistent.__setstate__, while generating no errors, fails to prevent the temporary entry from being written into the database. Please help, I need two answers! 1. How can I create a variable within a Product that will not be persistent (i.e. will not be written to disk)? 2. What function is called at normal shutdown? I need to call a function at shutdown to move the current value from temp to real. Note: The counter is usable as is, so if the list members think that Paul's now repudiated fear of constant disk growth is a non-issue, I could drop the temporary variable, and just keep the advantages of the interface, and the potential for an SQL based backend whilst keeping the same front-end. Thanks again. Howard C. Shaw III Programmer/SysAdmin St. Thomas High School

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Announcing FAQ 0.2.3
by Martijn Faassen 25 Mar '99

25 Mar '99

Hi there, Though the ZDP FAQ hasn't moved at the relentless pace it did before this week, there's still a new version of the FAQ at zdp.zope.org. It's a fairly minor change, but you might find some things that are useful to you. Of course, if you haven't seen it yet, go rush over! Happy Zoping, Martijn

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New Counter Product
by Shaw, Howard 25 Mar '99

25 Mar '99

Here is the updated Counter Product. This contains two classes, one which provides a visible Counter Product which can be added as an object, and which has Security options, and a new tag which provides a means of accessing the Counter Product. Note: the tag should be able to access ANY object which possesses a getCount() and a incrementCount(md) where md==_. So an SQLCounter Product which stores its numbers in an SQL database should be able to use the same tag structure. Since it passes md into the incrementCount, the Product is free to store as much or as little of the REQUEST as it chooses. My product stores only the IP address, and only under proper conditions. The tag structure is described in the CounterTag.py source file, and examples are given. I hope this is useful to someone. <<Counter.tar>> Howard C. Shaw III Programmer/SysAdmin St. Thomas High School

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RE: [Zope-dev] New Counter Product
by Michel Pelletier 25 Mar '99

25 Mar '99

> -----Original Message----- > From: Shaw, Howard [mailto:ShawH@STHS.org] > Sent: Wednesday, March 24, 1999 7:11 PM > To: 'Zope-Dev(a)zope.org' > Subject: [Zope-dev] New Counter Product > > > Well, it is basically finished and working, combining a > visible Product > interface and a counter tag... But, overriding __setstate__, removing > the temporary entry from the state, and called > Persistent.__setstate__, > while generating no errors, fails to prevent the temporary entry from > being written into the database. Please help, I need two answers! > > 1. How can I create a variable within a Product that will not be > persistent (i.e. will not be written to disk)? > Prefix your variable name with _v_. If you don't want the attribute foo to be persistent, call it _v_foo. > 2. What function is called at normal shutdown? I need to call > a function > at shutdown to move the current value from temp to real. > Uhm.. there isn't a shutdown hook for Products. Is this what your looking for? > Note: The counter is usable as is, so if the list members think that > Paul's now repudiated fear of constant disk growth is a non-issue, I > could drop the temporary variable, and just keep the advantages of the > interface, and the potential for an SQL based backend whilst > keeping the > same front-end. > > Thanks again. > > Howard C. Shaw III > Programmer/SysAdmin > St. Thomas High School > -Michel > > _______________________________________________ > Zope-Dev maillist - Zope-Dev(a)zope.org > http://www.zope.org/mailman/listinfo/zope-dev > > (For non-developer, user-level issues, use the companion list, > zope(a)zope.org, http://www.zope.org/mailman/listinfo/zope ) >

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RE: [Zope-dev] New Counter Product
by Shaw, Howard 24 Mar '99

24 Mar '99

Well, except for the debugging and the interconnection of the class that provides the tag with the class providing persistence its almost done, assuming the Persistent.__setstate__(self,state) call works. BTW, is it a bad thing for me to modify state, or should I modify a copy of state, and pass that instead? What does the list think? Should I just run with Counter as written, or write the update? The advantages of the update should be... * Compresses updates by a specified amount. I.e. doesn't write to db until X hits go by * Has visible management interface * Doesn't clutter up folder properties * Has security (You can prevent X from using counters, while allowing Y to) * Separates rendering from recording so rendering can occur in disparate locations from same counter * Should be easier to generate separate product with matching interface that uses SQL DB to store info and/or product that stores more info than just the IP, but use the same rendering tag... (I think...) The disadvantages would be... * More complicated source code * Requires adding a Counter object AND a tag, rather than just a tag Howard C. Shaw III Programmer/SysAdmin St. Thomas High School > ---------- > From: Paul Everitt[SMTP:Paul@digicool.com] > Sent: Wednesday, March 24, 1999 4:33 PM > To: 'Shaw, Howard' > Subject: RE: [Zope-dev] New Counter Product > > > Howard wrote: > > addition to > > the database of 4K. I am not sure that this is a significant > > amount, but > > I retract my statement. You're right -- it doesn't warrant the extra > complexity, so consider your hit counter contributed! > > --Paul >

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func called when Zope closes?
by Shaw, Howard 24 Mar '99

24 Mar '99

What function of the Product does Zope attempt to call during a normal shutdown to inform it that the system is going down? Howard C. Shaw III Programmer/SysAdmin St. Thomas High School

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RE: [Zope-dev] New Counter Product
by Shaw, Howard 24 Mar '99

24 Mar '99

Read Paul's message in the Zope list. He pointed out that because the ZODB uses a logfile structure (i.e. an append based mechanism where changes are appended rather than overwritten) something such as a counter which changes with each access will write to the database (appending, not overwriting) with every access. On a site with enough traffic to really warrant a counter, this could cause the database to grow significantly in a short amount of time. Can you imagine the amount of writing if the server got Slashdotted? Since my code uses Longs, which are (I assume) stored as strings (since no binary format exists to handle arbitrary lengths) wherefore a base count of 4000 hit by a Slashdot effect resulting in a 1000 hits results in a minium addition to the database of 4K. I am not sure that this is a significant amount, but Paul seems to think it would be better if the hits were accumulated before being written. This requires some place to temporarily store data... persistently as far as memory is concerned, but not persistent with regard to disk storage. The only way I can think to do this at the moment is to create a persistent Product, and force some of its attributes to fail to be seen by the persistence mechanism. At this point, my primary question is how do I, within my own __setstate__, call the original __setstate__? My guess is Persistent.__setstate__ and pass self in manually, but I would welcome advice. Thanks again. Howard C. Shaw III Programmer/SysAdmin St. Thomas High School > ---------- > From: Mike Pelletier[SMTP:mike@compar.com] > Sent: Wednesday, March 24, 1999 3:48 PM > To: Shaw, Howard > Subject: Re: [Zope-dev] New Counter Product > > > I don't understand... Why does the underlying persitance > mechanism matter > at all? And why do you want to not pickle certain instance > attributes? If I > knew that, it would be much clearer to me. > > Mike. > > > -- > --- | Mike Pelletier Work: > 519-746-1607 > /opeware! | Software Developer Home: > 519-725-7710 > --- | mike(a)zopeware.com Fax: > 519-746-7566 > http://www.zopeware.com | Zopeware is not endorsed by Digital > Creations >

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ZopeHTTPServer patch for userid
by Christopher Petrilli 24 Mar '99

24 Mar '99

Gang, I was bored, annoyed with this silly being forced to run something as nobody (since I'm using ZopeHTTPServer), and since it's a trivial fix, attached is a patch that behaves the same by default, but adds a command line option to ZopeHTTPServer which lets you specify the userid tor un as (obviously you must be able to change your userid)... it's still defaults to nobody. The option is.... </drumroll> -u ;-) You can also find the patch verbatim on the web: http://www.amber.org/petrilli/Technical/Python/Zope/ZopeHTTPServer.py.patch Have fun... bitch at me ;-) CHris -- | Christopher Petrilli ``Television is bubble-gum for | petrilli(a)amber.org the mind.''-Frank Lloyd Wright

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