July 1999 - Zope - Zope lists

RE: [Zope] Re: creating ZClasses with external method
by Brian Lloyd 13 Jul '99

13 Jul '99

> Alex> I still cannot create ZClasses with an external method (using > Alex> aquisition) Since I can do it with ZPublisher.Client > and by typing > Alex> in a URL into my browser, but not via an external > method, this is > Alex> really seeming like a bug. Should I report this to Collector? > <snip> > > It looks so easy in retrospect :-) This method below works a like a > charm. I adapted this from Brian Lloyd's post today to zope-dev > (subject: ZClasses instances become detached from class). > > def addFoo(self, id='a_obj', REQUEST=None): > """ """ > # Get the actual destination object, using the this() > # method, to be sure we get it in the right context.. > self=self.this() > > # Create the new instance > newob=self.Control_Panel.Products.Foo.foo(id) > # redundant? > newob.id=id > > # Set properties based on the contents of the Add form > newob.propertysheets.info.manage_changeProperties(REQUEST) > > # Add the new instance to the target object > self._setObject(id, newob) > > return 'OK!' > > Question: why the heck does one need to call self=self.this()? In what > cases does it make a difference? That's just weird. Is this() def'd in > SimpleItem.py? > > Alex Rice Well, using the this() method is necessary because of the behind-the-scenes trickery that is actually going on when you create a new object. If you look at the target URL when you create an object, it looks something like: /myFolder/manage_addProduct/OFSP/folderAdd The 'manage_addProduct' method of ObjectManagers is actually a FactoryDispatcher object that masquerades as a method. It implements the trickery to find the right product and constructor, etc. The upshot is that when you actually submit the add form for an object, it is submitted to a constructor that is several levels deeper in the URL hierarchy than the actual destination where you are creating the new object. It is going through the destination object, a factory dispatcher, and the factory for the object itself to get to the object constructor. The constructor, of course, often wants to use the 'self' object, and expects it to be the parent object that the new object will be living in. However, as you can see above, the 'self' that you see in your external method is very likely going to actually be the _Factory_ object (which actually contains the constructor). Because of that, you need to set 'self' to the actual destination where the object will be living - we used to call self.Destination() to get that object, but the this() method has been made an alias for the old Destination() method. Using "self=self.this()" in your external method will set 'self' to the actual destination object. While this may be kind of unintuitive, it is a necessary evil that you have to set the destination to the right thing yourself, because your constructor may want to use attributes of the Product itself. For example, above, you created your ZClass above with the line: # Create the new instance newob=self.Control_Panel.Products.Foo.foo(id) It would be better in this case (to avoid hard coding product names and locations) to use 'self' in its initial context (the factory), and defer setting self to this() until after you are done using attributes of the Product/ Factory: def addFoo(self, id='a_obj', REQUEST=None): """ """ # Create the new instance. Here, self is still # the Factory, which can acquire the ZClass that # we want to instantiate (foo) from the Product. newob=self.foo(id) # Now we're done using things from the Factory or # Product, so set self to the actual destination # object where our new instance will live. self=self.this() # Set properties based on the contents of the Add form newob.propertysheets.info.manage_changeProperties(REQUEST) # Add the new instance to the destination object (which # is self at this point). self._setObject(id, newob) return 'OK!' The gory details of how this stuff works can be found in the App package in Zope (Product, Factory, FactoryDispatcher, etc.) Hopefully this explanation helps a bit - let me know if it did more harm than good, and maybe I can get Jim to explain it better... :^) Brian Lloyd brian(a)digicool.com Software Engineer 540.371.6909 Digital Creations http://www.digicool.com

2 1

Re: [Zope] any streaming audio formats that Zope can serve?
by Anthony Baxter 13 Jul '99

13 Jul '99

>>> Martin Dougiamas wrote > > Are there any "streaming" type audio formats that don't require a special > > server? Then Zope could just deliver this to ZServer (or Apache) and let it > > stream the data to the end system. > MP3 streams very well. eg http://www.icecast.org and http://www.shoutcast.com > And there are free versions of decoders and encoders. http://freshmeat.net Played a bit with this - mp3 is expensive to encode, and also isn't all that great for compression for the data I have. The data I have is 12 bit 6kHz sound samples, and it's necessary to convert it to a much higher resolution format to use it with MP3. > Realaudio also streams pretty well over http. I need to be able to convert data on the fly - unless things have changed, the realaudio sound format converters are expensive, and just not very good. Current plan is to play with using the Quicktime4Linux library to stream the data. I'll post more when I have had more of a play. (For those that are interested: the application in question is to allow a user to browse a voice message box, and select voice messages to play. It currently delivers a .wav file (generated by an external method) and the browser downloads it before playing... Anthony -- Anthony Baxter <anthony(a)interlink.com.au> It's never too late to have a happy childhood.

2 1

RDBMS-backed ZClasses
by Petru Paler 13 Jul '99

13 Jul '99

Is it possible to have a ZClass that has some attributes in sync with a database table ? Each instance should be a record in the database table. Example: you have a FooClass with the a1 string , a2 and a3 integer attributes. In the same time you have a database table: create table foo ( a1 varchar(255), a2 integer, a3 integer ); When you add a FooClass instance a row should be added to the database and when you edit it the row should be updated. Ditto for deletion. -Petru

1 0

Re: [Zope] Zope and Apache vs ZAP? Which server to use?
by Kam Cheung 13 Jul '99

13 Jul '99

>> What's the difference between Zope+Apache and ZAP? Which do >> you recommend I >> use? >> > > There's no real difference. Zap is apache. Even if you compile and use > your own Apache, however, it is still quite useful to use Zap's .conf > file as a template for you own. Isn't Zap's Apache an older version than the current v1.3.6 ? Kam

1 0

Re: [Zope] Zope and Apache vs ZAP? Which server to use?
by Kam Cheung 13 Jul '99

13 Jul '99

> Anyway, which server should I use? > > I'm guessing the Zope Server is not what I want. > > What's the difference between Zope+Apache and ZAP? Which do you recommend I > use? Philip, Nice to see you here. I am a Frontier user also!! Your timing is perfect, since I just started using Zope as well. I installed Zope last weekend. My suggestion to you is, if you really want to learn Zope, try using it with your own Apache. To me, it turned out to be the most difficult part of the whole process. And, according to messages in the archive of this list, many people were having problem with this as well (you might be the lucky one, though). However, definitely download Zap, you should be able to learn how to configure your Apache by looking at Zap's conf file. What version of Linux are you running? If you are running RedHat Linux 6, and is using its bundled Apache 1.3.6, I can give you my conf file. That should help you get started. BTW, it takes me a while to get used to how Zope handles templates. It's quite different than Frontier. The way how Frontier handles inherited templates, pageheader, and pagefooter is definitely more advanced than how Zope does it (as far as I know, if I am wrong, someone please correct me and I am more than happy to know how to do it). Kam On Cheung

1 0

RE: [Zope] Object reference in Zope???
by Michel Pelletier 13 Jul '99

13 Jul '99

> -----Original Message----- > From: Kam Cheung [mailto:zope@littlecircle.com] > Sent: Monday, July 12, 1999 9:45 PM > To: Zope List > Subject: [Zope] Object reference in Zope??? > > > Thanks for everyone who has helped me on this problem. It > turned out that > there is something wrong with my permission setting. > > However, I am still not very clear what is the best way to refer to a > subfolder object in Zope. > > Here is what I find out so far: > > Let's say I have a site like this > > Home > index_html > testing > data > testing > > 1) Problem One > When I am in index_html, I can refer to Home.testing by doing: >  > > But if I want to display Home.data.testing in index_html, > I have to do: >  alternativly you can do:    > > NOTE: , without the double quote, > doesn't cut it. Also, if I want to see Home.testing's > title, I have to do , not >  > To use the python dot (.) operator, you must use an expression because it needs to be evaluated. > > Question: What's the reason behind this inconsistency of reference? > Given the excellent work the Zope team has shown in the > product, I am sure that there must be a reason, right? > This might be a little strange, but it's not inconsistent. The dot operator needs to be evaluated therfore it goes in double quotes. unquoted arguments (referencing by name) is a simpler case for when you just want the object to take care of itself. If you want to be picky about what on the object you want (a certain atribute, calling a method...) you must evaluate it. > > 2) Problem Two > Let's say in index_html, I have a string property called "pageID", and > "pageID" equals to the string "testing". > > Now, if I want to use the "pageID" to refer to the two "testing" > documents, I thought I can do: > >  > or >  > > But they don't work. What I end up doing is: >  > > That work. The problem is, how can I get "Home.data.testing"? >  surely won't work, >   !--#/with--> I'm not sure, but I believe:    will work. won't take long to find out! ;) > but I am surprised that even if I spell out the full path, it still > wouldn't work: >  > nor does >  > getitem cannot resolve objects through the dot operator. it expects a string which it uses to find an attribute by the same name, it cannot find attributes of attributes. > What I end up doing is: >  >  >  > exactly. > > Question: What is the preferred to do that? Is there a better method? > Why can't I simply refer to an object inside "_.getitem" using > a format like "xxx.yyy"? > That's just the way getitem works, this is how it comes from Python. It's actually quite consistent. -Michel

1 0

RE: [Zope] External method: import error
by Michel Pelletier 13 Jul '99

13 Jul '99

> -----Original Message----- > From: HCSCCS(a)prudential.com.my [mailto:HCSCCS@prudential.com.my] > Sent: Tuesday, July 13, 1999 4:06 AM > To: zope(a)zope.org > Subject: [Zope] External method: import error > > > Hi Zopiens! I'll start with one question... is Zope stable to > use thus > far? > 1.10.3 is extremely stable. > Anyway, back to my problem. I have Zap (pre-built Zope with Apache) > running on Red Hat 5.2 machine. I also put all my customize Python > scripts in the Extensions directory of Zope. > > Recently I wrote a script file to access a Postgres database > and this > file is called by other scripts whenever database access is > needed. Now I > got a problem of "importing" the database script from other > scripts. Why > so? I have tried to include the Extensions directory in the > PYTHONPATH, > but it doesn't work. > The import may be failing, is it rasing an exception on import? That may appear like it's not finding it, when really the import is failing. -Michel > Thanks for any suggestion or solution given. > > PauL ChunG > > > _______________________________________________ > Zope maillist - Zope(a)zope.org > http://www.zope.org/mailman/listinfo/zope > > (For developer-specific issues, use the companion list, > zope-dev(a)zope.org - http://www.zope.org/mailman/listinfo/zope-dev ) >

1 0

RE: [Zope] documentation bugs
by Michel Pelletier 13 Jul '99

13 Jul '99

> -----Original Message----- > From: Alexander Staubo [mailto:alex@mop.no] > Sent: Monday, July 12, 1999 5:58 PM > To: Zope Mailing List (E-mail); bruce(a)perens.com > Subject: RE: [Zope] documentation bugs > > > Which raises the issue of whether perhaps -- as much as it's an > excellent tool for documentation -- FrameMaker is the ideal > tool to use > here. Other formats (XML/SGML, TeX) come to mind that are > better suited > for the collaborative environment of an open-source project. > I don't like Frame because I can't run it on my computer, but to quote Jim, the problem with out documentation isn't what tool it's written in, but the quality and quantity. Granted a more 'cross-platform' tool would be better in my opinion, and also one which followed a more open format. I'm going to be looking into some XML stuff for an upcomming documentation project, a side effect of which might be implimented here. I have a lot of time put into lyx (WYSIMYM TeX editor for Linux) and I find it quite usable, but it's image handling is pretty poor, and it also is not cross platform the other way... many people here use Windows, or MacOS, on their desks to client into our Linux and Solaris servers. -Michel > -- > Alexander Staubo http://www.mop.no/~alex/ > "He could open a tin of sardines with his teeth, strike a Swan Vestas > on his chin, rope steers, drive a steam locomotive and hum all the > works of Gilbert and Sullivan without becoming confused or breaking > down in tears." > --Robert Rankin, _The Book of Ultimate Truths_ > > >-----Original Message----- > >From: zope-admin(a)zope.org [mailto:zope-admin@zope.org]On Behalf Of > >bruce(a)perens.com > >Sent: 12. juli 1999 23:37 > >To: zope(a)zope.org > >Subject: [Zope] documentation bugs > > > > > >I was about to send a patch for spelling errors in the content > >manager's > >guide, but then I realized that the original was written in > >FrameMaker and > >isn't accessable to me. Someone definitely has to push the > spell-check > >button on these pages. > > > > Thanks > > > > Bruce > > > >_______________________________________________ > >Zope maillist - Zope(a)zope.org > >http://www.zope.org/mailman/listinfo/zope > > > >(For developer-specific issues, use the companion list, > >zope-dev(a)zope.org - http://www.zope.org/mailman/listinfo/zope-dev ) > > > > > _______________________________________________ > Zope maillist - Zope(a)zope.org > http://www.zope.org/mailman/listinfo/zope > > (For developer-specific issues, use the companion list, > zope-dev(a)zope.org - http://www.zope.org/mailman/listinfo/zope-dev ) >

1 0

RE: [Zope] documentation bugs
by Michel Pelletier 13 Jul '99

13 Jul '99

> -----Original Message----- > From: bruce(a)perens.com [mailto:bruce@perens.com] > Sent: Monday, July 12, 1999 5:06 PM > To: zope(a)zope.org > Subject: [Zope] documentation bugs > > > I was about to send a patch for spelling errors in the > content manager's > guide, but then I realized that the original was written in > FrameMaker and > isn't accessable to me. Someone definitely has to push the spell-check > button on these pages. > I forwarded this to our new technical writer, who I believe is working on revising all existing guides. I do remember her mentioning we should use the psell checker more ofte... -Michel > Thanks > > Bruce > > _______________________________________________ > Zope maillist - Zope(a)zope.org > http://www.zope.org/mailman/listinfo/zope > > (For developer-specific issues, use the companion list, > zope-dev(a)zope.org - http://www.zope.org/mailman/listinfo/zope-dev ) >

1 0

RE: [Zope] Cutting, copying and pasting products
by Jeffrey Shell 13 Jul '99

13 Jul '99

> It is possible to move folder objects around, but products > can supposedly only > be cut, copied and pasted in the products directory. Could > anyone give a > rationale for this? The Products Folder is a special object for, naturally, Products -- both disk-based (ala the primary built in Zope products, as well as any others) and Zope-based (Products that are instantiated using Factories). Remember that Zope Folders are not directories, but are actual objects, and some objects may act folder-ish but be very specialized and may only allow certain types of objects. (Similar to the Control Panel in Windows 9x, and /dev type directories on Unix). The Products Folder is one of these types of Objects. I believe the rationale was as a centralized product management area (letting you see what Products where installed with the system), and as a development area for through-the-web products.

3 3