April 2000 - Zope - Zope lists

Is it just me?
by Daniel.Weber＠SEMATECH.Org 09 Apr '00

09 Apr '00

<RANT> Well, after fixing about the hundredth instance in my code of dmtl instead of dtml, I have to ask the question - why the heck couldn't it be <z-var ...> instead of <dtml-var>? it's gotten to the point where I'm going to hack the code to spell-check for dmtl.... </RANT>

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Re: [Zope] Storing an object in RAM during Zope's up-time
by Hung Jung Lu 09 Apr '00

09 Apr '00

--- In zope(a)egroups.com, "Li Dongfeng" <ldf@s...> wrote: >I'm afraid that the only way to keep an object in RAM >but not as a percistent object is to define the variable >in a product's global space. Thanks for answering. There are several ways to implement Zope up-time variables. But I just find it interesting that so few people has looked into my message. :) (Except you and Pavlos.) Using a product is an overkill. You can use any Python module. Since Digicool has the Globals.py module, we might as well use that one. That seems a nice place, better than using Python built-in modules. (If you really want to, you can even use the __builtins__ module instead of the Globals module, but I think that's a bit too drastic and too Perl-ish.) As the good and nice person that I am [heh heh :)], I include actual code so other people can play a bit, too. Implement an external method getMyVar() inside myExternal.py: ---------------------------------------- import Globals def getMyVar(self): if not hasattr(Globals, 'myVar'): Globals.myVar = 0 Globals.myVar = Globals.myVar + 1 return Globals.myVar ---------------------------------------- Voila, there you have a non-persistent variable that is: (1) Global to all threads, and (2) Has a lifetime equal to Zope's uptime. You can play around with different browser sessions and also reboot the Zope server to verify these features. --------------------------------------------------------- You might ask thread safety, and I would say this is a big issue. I haven't looked into Python threads lately, but I seem to recall that Python is borrowing Java's thread model... which almost makes me want to scream. When JDK 1.0 came out, I couldn't believe they let a total novice implement the thread features... Sure enough, most of the JDK 1.0 thread feature were quickly scrapped and the thread model in JDK 1.1 were better, but equally stupid because at no time are you guaranteed exclusive time-slice in a line of code, which in practice means you have to rely on primitive locking mechanisms that send you into deadlock minefields whereever you go. Jave doesn't allow exclusive time-slice (or a global lock) due to security concerns. But this makes thread programming really painful. Hopefully Python doesn't repeat the same mistake of Java. We really really need exclusive time-slice at least for some of the basic Python operations. Funny thing is that thread programming has been around town since a long time ago, but I don't understand why they let all these grandious novices dictate and screw up everything. :) ------------------------------------------------------------ In short, keep in Globals only those variables that you read a lot but write just a little. :) Sorry for digressing so much, but a bad Java experience haunts me a lifetime. :) regards, Hung Jung ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

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SQLmethods in a product...
by John Sutherland 09 Apr '00

09 Apr '00

This is going to take a bit to explain, so bear with me... I'm trying to create a python based product, where in the __init__ for the class, I write some data to a SQL DB (in this case MySQL..)... Using the code from SQLSession's as an example, I followed his method of making SQL statements in a class.. My problem comes in when I try to create an instance of the class, it tells me that the database adapter that I chose couldn't be found.. I've tried creating the database adapter in the same folder that I'm trying to create the instance, and all the folders up to the root one, without success... Could this be because I'm trying to access it in the __init__ function?? If I'm not clear, please let me know, and I'll forward some code up... --John

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International character sets - GB/BIG5 Chinese
by Paul Gresham 09 Apr '00

09 Apr '00

Hi, I was looking for more info on double-byte internationalisation and whether it is supported in Zope. Is there anything special required to make it work? I didn't find very much scanning through the mail archives. Any info would be greatly appreciated. Regards Paul Gresham www.mediavisual.com

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render/parse function ? (using <dtml-var x> in a property sheet ?) sheet ?)
by chas 09 Apr '00

09 Apr '00

Sorry to bother you all again, but solving this problem would save a lot of jumping through hoops and I was surprised that nobody else has encountered it. Consider : - we have a ZClass string property called 'myproperty'. - we set the value of 'myproperty' to "Hello <dtml-var FirstName>" where FirstName is a variable whose value is set to 'Fred' - we now try to render the value of 'myproperty' inside a DTML method using the DTML : <dtml-var myproperty> - as would be expected, the following is displayed - "Hello <dtml-var FirstName>" since it is just a string. But really we wanted it to display "Hello Fred" ie. to evaluate the DTML tags. Is there any method that can be called to parse the value of a property and evaluate the DTML ? Thank you very much, chas ps. To circumvent the above, I could create a DTML method called 'myproperty'. However, with 30 such properties it would be far nicer and faster to edit them in ZClass property sheets. I guess it would be nice if there were some ZClass property of type 'renderThis' where the contents will be rendered by Zope just as a DTML method's contents are. In lieu of this, any hacks would be appreciated :)

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ZCatalog and dictionary python instances variables (QUEST)
by Oscar Picasso 09 Apr '00

09 Apr '00

Hi, I' trying to use ZCatalog to index some values stored in a dictionary. The dictionary is an instance variable of a python class which is a base for a ZClass. **my python class** class Multi: def set(self): self.a = 'The a attribute' self.b = {'one' : 'un', 'two': 'deux', 'three': 'trois'} ZMulti is a ZClass derived from Multi, and multi is a ZMulti instance. Before Cataloging my object I run: <dtml-call "multi.set()"> Works fine: <dtml-var a> returns 'The a attribute' <dtml-var b> returns {'one' : 'un', 'two': 'deux', 'three': 'trois'} If i try to catalog multi with the Find tab, it works fine index : a but not for b. I've tried index : b (type TextIndex) index : b (type FieldIndex) index : b['one'] (type TextIndex) index : b['one'] (type FieldIndex) But it never works. Any help greatly appreciated.

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Re: [Zope] GUF: Generic User Folder
by Hung Jung Lu 09 Apr '00

09 Apr '00

OK, I know some of you are out there watching. :) Here is what I found out you can do to use Zope's folder security features using your own user info database, your own login interface, and without using GUF (Generic User Folder). It's kind of simple, so don't expect too much. :) Hey, but at least it does not lock you up and send you into a panic attack. :) (1) Have your own login interface, and use some session management product or cookies to keep track of whether the user has been authenticated by you. (2) Create additional user-defined roles at the root of your Zope project. (Click on the 'Security' tab of the root folder, and scroll to the bottom.) E.g: 'teacher', 'student', 'parent', etc. (3) Create an acl_users folder at the root of your Zope project. Inside the acl_users folder, add new generic users. E.g: 'GenericTeacher', 'GenericStudent', 'GenericParent'. Assign non-trivial passwords to them, of course. (4) In your standard_html_header or equivalent, you then check against your cookies or session data. If the user is a teacher, then call: <dtml-call "REQUEST.set('AUTHENTICATED_USER', acl_users.getUser('GenericTeacher'))"> Voila! Now you can use Zope's security settings to prevent people from accessing given folders. Hung Jung ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

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DTML method's contents accessible but not viewable within a class definition ? class definition ?
by chas 09 Apr '00

09 Apr '00

Having spent the better part of the night getting nowhere with this, I hope somebody can help. Consider a DTML method (called 'content') which is part of a ZClass as follows : /Control_Panel /Products /MyProduct /MyZClass content [dtml method] Is there no way to protect the DTML method so that it cannot be accessed directly from instances of this ZClass ? eg. if we create an instance of MyZClass in the Zope root : /MyInstance I don't want people to be able to call : http://Zope_server/MyInstance/content But we would like other DTML documents/methods such as http://Zope_server/MyInstance/index_html to be able to access the contents using "<dtml-var content>" I've been getting nowhere with the "Define Permissions" tab of the 'content' DTML method in the ZClass definition - it's simply not possible to disable the 'view' property. Thank you in advance if anybody can offer any suggestions here, chas

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Re: [Zope] Storing an object in RAM during Zope's up-time
by Hung Jung Lu 08 Apr '00

08 Apr '00

>From: Michel Pelletier <michel(a)digicool.com> >Hung Jung Lu wrote: > > but I seem to recall that Python is borrowing Java's > > thread model... which almost makes me want to scream. > >I don't think this is true, there are actually two thread extensions for >python, one is low-level and one is high-level. It might be true that >the high-level on is Java-esque, but the low-level one is very >straightforward. That's nice, yes, I was just looking into the two modules. But I'd like to know more, so I just send a message to Dag Gruneau (the person that implemented the NT thread part), too. >I believe almost all of the basic type operations in Python are thread >safe, such as list.append(), if this is what you mean by 'exclusive >time-slice', I'm not very up on the lingo. Well, in Java, you can have the two lines: i = 3; System.out.println(i); and it would print out 4 instead of 3, because between the first line and the second line some other thread has sneaked in and modified the value of i. That's the scary part. You have no exclusive time-slice (or in other words, the above two statements is non-blocking as a whole.) That is, the above two lines of code don't own the CPU time exclusively: some other thread may sneak in. (You draw a chart of owner-thread of CPU time, and different threads get slices of the CPU time. Say, thread 1 uses CPU from 2000/03/21 03:32:54.323 to 2000/03/21 03:32:54.345, that's one slice. And thread 2 uses CPU from 2000/03/21 03:32:55.345 to 2000/03/21 03:32:54.367, that's another slice.) In order to prevent that, you use a lot of "synchronized" keywords in Java, which blocks all other accesses to an object. But the downside is that it can cause deadlocks. regards, Hung Jung ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

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for linux, python-devel?
by Charlie Derr 08 Apr '00

08 Apr '00

Hi all, I've got zope running in a windoze environment, and i'm playing with and slowly learning. I tried to install the rpms to run it in linux, but i get a dependency error saying "python-devel" not installed. I've got redhat 6.1 and obviously python is present. Where do i find python-devel? TMIA, ~c

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