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Re: [Zope-dev] Using Zope in a client-server system
by Itai Tavor 08 Mar '00

08 Mar '00

Tres Seaver wrote: >Itai Tavor wrote: > > > > Tres Seaver wrote: > > > > > > By default, browsers aren't servers: they don't know from > > > bind()/listen()/accept(), which is what push technology requires (unless > > > you have a long-running, bi-directional connection between browser and > > > server, which HTTP doesn't allow). Polling is the only >"native" technique > > > for refresh, and suffers from _horrible_ scalability problems. > > > > > > Options in order of simplicity: > > > > > > 1. Pull instead of push (ick!) > > > > My sentiments exactly. > > > > > 2. As Hung Jung suggests, build the "push model" stuff >separately from the > > > browser, using Python or Java to implement HTTP (and >perhaps XML-RPC?) > > > Integration with the browser is difficult: clients will >have to have > > > some mechanism for registering their mini-server with your server; > > > if you want the broser's display to update when the push event comes > > > in,you may be stuck. > > > > Right. Mixing two GUI's - a browser for most of the interface and a > > separate app for pushed data - would be real ugly. So I either have > > to work inside the browser, as in option 3 below, or code my own GUI. > > > > Registering the mini-servers would not be a problem. This project > > will be running on a small number of workstations, all located in one > > location. It's not designed for public or wide-area use and won't > > even be connected to the internet. > >If you control the deployment platform, and the pipe between client >and server, >then some of my tradeoffs don't apply, as you note: trusted applets are >reasonable, for instance, and polling is not nearly as terrible a >strategy over >a fast network with a small number of clients. Yeah... which brings me to making the choice to stick to the original plan of putting all the client UI inside a browser. > > < snip > > > - Would it still be a good idea to use Zope for the server, or should > > I code the server as well (a full Java solution comes to mind using > > COBRA for two-way communication). How would I handle push in Zope? > > Assuming I code a push client that speaks XML-RPC, how do I get Zope > > to send data outside the context of an http transaction? Actually, > > this same question is relevant for the solution of using a Java > > applet within the browser. > >You might look at Loren Stafford's recently-announced ZScheduler >product: Loren >is working on a way to have "internally-generated" events fire inside Zope. I've been forced away from Zope by other work, the current status of ZScheduler is one thing I need to catch up on. > > - Two good candidates for writing the GUI in are Java and wxPython. > > Using wxPython would have the advantage of keeping everything in > > Python. On the other hand, there's an XML-RPC server for Java, but > > not for Python - I guess I would use HTTP if I use wxPython. Can > > anyone suggest pros/cons for these solutions? > >I think I missed something here: Python *does* have an XML-RPC server >implementation (xmlrpclib.py), which is how Zope can do XML-RPC. I was thinking that for real two-way communication, the workstations will also have to be XML-RPC servers, and while I know that Zope can do that I have no idea how hard it would be to get xmlrpclib working outside Zope. But that's not really an issue if I use polling. > > I have one other question related to the use of Zope in this project: > > The server has to monitor a serial line and respond to received data > > by pushing messages to the clients. What would be the best way to > > achieve this? An external python process reading the serial line and > > calling ZPublisher.Client to triger a DTML method that will do the > > rest of the work? > >Right, but ot necessarily a DTML Method. The ZClient request might, for >example, trigger a method of a Python product instance, which could >enqueue the >event for processing by a notification thread, for instance. Ok. My main concern was how to get the external event into Zope, once I achieved that it will probably be dealt with using a product or a Python method. > > P.S. I know this is getting way off topic for the Zope group. I > > really appreciate all of you contributing your experience. > >I don't think this is off-topic at all -- we are pushing the *normal* Zope >envelope a bit, but I think Zope is up to the challenge. Glad to be pushing my little corner of the envelope :) -- Itai Tavor -- "Je sautille, donc je suis." -- itavor(a)vic.bigpond.net.au -- - Kermit the Frog -- -- "What he needs now is understanding... and a confederate victory" -- -- Dr. Jacobi, Twin Peaks --

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TinyTable object type is Shared.DC.ZRDB.Results.Results???
by Itai Tavor 08 Mar '00

08 Mar '00

Hi, I create a TinyTable object. Then I run the following code: <dtml-in "objectItems('TinyTable')"> <dtml-var sequence-item fmt=html-quote> </dtml-in> I get this: <Shared.DC.ZRDB.Results.Results instance at 8628c78> Welcome to the Twilight Zone. What's happening here? This really gets in the way when I try to access the TinyTable object from a ZCatalog search: <dtml-in Catalog> <dtml-with "Catalog.getobject(data_record_id_)"> <IMG SRC="<dtml-var icon>"> <dtml-var id> </dtml-with> </dtml-in> This displays the correct icon and id for all objects other than TinyTable. For TinyTable this displays the Catalog icon, and the <dtml-var id> returns Unauthorized, even for Manager. Any ideas? Itai -- Itai Tavor -- "Je sautille, donc je suis." -- itavor(a)vic.bigpond.net.au -- - Kermit the Frog -- -- "What he needs now is understanding... and a confederate victory" -- -- Dr. Jacobi, Twin Peaks --

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ZCatalog
by Tom Deprez 08 Mar '00

08 Mar '00

Is there a way to see which keywords, etc are indexed in a catalog? eg. Let's say I indexed the title of a class and now I want to see all the titles in the catalog (so I can see if I'm programming correctly) Thanks tom.

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Errors searching ZCatalog
by Itamar Shtull-Trauring 08 Mar '00

08 Mar '00

Every once in a while our ZCatalog (from CVS) seems to get "corrupted" - usually one (or maybe more) items cause the following error whenever they come up in a search for certian search terms. For example today I seached for "tomato" (/recipe/manage_catalogView?title=recipe) and got this error: Error Type: KeyError Error Value: 431 Traceback (innermost last): File /home/zope/lib/python/ZPublisher/Publish.py, line 214, in publish_module File /home/zope/lib/python/ZPublisher/Publish.py, line 179, in publish File /home/zope/lib/python/Zope/__init__.py, line 211, in zpublisher_exception_hook (Object: ElementWithAttributes) File /home/zope/lib/python/ZPublisher/Publish.py, line 165, in publish File /home/zope/lib/python/ZPublisher/mapply.py, line 160, in mapply (Object: manage_catalogView) File /home/zope/lib/python/ZPublisher/Publish.py, line 102, in call_object (Object: manage_catalogView) File /home/zope/lib/python/App/special_dtml.py, line 120, in __call__ (Object: manage_catalogView) (Info: /home/zope/lib/python/Products/ZCatalog/catalogView.dtml) File /home/zope/lib/python/DocumentTemplate/DT_String.py, line 502, in __call__ (Object: manage_catalogView) File /home/zope/lib/python/DocumentTemplate/DT_In.py, line 592, in renderwb (Object: searchResults) File /home/zope/lib/python/Products/ZCatalog/Lazy.py, line 190, in __getitem__ File /home/zope/lib/python/Products/ZCatalog/Catalog.py, line 187, in __getitem__ KeyError: (see above) I discovered the entry that causes this, and it seems to be cataloged okay - i.e. if I'm just browsing the catalog it displays fine, and in some searches it displays fine. Only when I search by specific words in the title it gives an error - and not all words. Updating the catalog solves the problem. It's title is "Tomato Bread Salad", which doesn't seem to have any wierd characters or anything. -- Itamar S.T. itamars(a)ibm.net

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Re: [Zope-dev] Using Zope in a client-server system
by Tres Seaver 08 Mar '00

08 Mar '00

Itai Tavor <itavor(a)bigpond.net.au> > > Tres Seaver wrote: <snip> > > > >I think I missed something here: Python *does* have an XML-RPC server > >implementation (xmlrpclib.py), which is how Zope can do XML-RPC. > > I was thinking that for real two-way communication, the workstations > will also have to be XML-RPC servers, and while I know that Zope can > do that I have no idea how hard it would be to get xmlrpclib working > outside Zope. But that's not really an issue if I use polling. xmlrpclib.py is a normal Python module, published by the F-bot; I expect it will be part of the Python 1.6 distribution, for instance. It comes "out of the box" with a trivial server implementation, I think. Tres. -- ========================================================= Tres Seaver tseaver(a)palladion.com 713-523-6582 Palladion Software http://www.palladion.com

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ZCatalog: Forgot to mention
by Tom Deprez 08 Mar '00

08 Mar '00

Oops, forgot to mention of course that I 've set added 2 indexes in the catalog which point to the 2 methods : getParentEx and getParents_html Tom.

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Re: [Zope-dev] unpickleable error
by auto44082＠hushmail.com 08 Mar '00

08 Mar '00

>Ive run into this several times, and you've prompted me to look into >why. > >I think manage_changeProperties and manage_editProperties should be >using self._updateProperty rather than self._setPropValue. > >self._updateProperty performs type checking on the property values. >In >this case you property would probably get the value ><file object at 0x12345678> >or something similar, which gives a good hint about what you did >wrong. Interesting... I finally fixed my problem without understanding completely why. I ended up deleting the property in question ("upload_file") with manage_delProperties, and re-adding it with manage_addProperties. This worked fine and I was on my way. Unfortunately I don't understand enough about Zope and the underlying Python to see immedately what I did wrong originally. It seems to me that manage_changeProperties should work too. Am I passing a reference to the file object instead of the file object itself? (Forgive my dullness, but I'm not a python expert yet :) -Andy IMPORTANT NOTICE: If you are not using HushMail, this message could have been read easily by the many people who have access to your open personal email messages. Get your FREE, totally secure email address at http://www.hushmail.com.

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Tree expand_all bug
by Jason Spisak 08 Mar '00

08 Mar '00

I've got a very simple tree tag and want all items to be expanded upon initial viewing. <dtml-tree branches_expr="objectValues()" sort=id> <dtml-if "meta_type=='Folder'"> <IMG SRC="<dtml-var icon>" BORDER=0> <dtml-var title> <dtml-else> <A HREF="<dtml-var tree-item-url>"> <dtml-if "title!=''"> <IMG SRC="<dtml-var icon>" BORDER=0> <dtml-var title></A> </dtml-if> </dtml-if> </dtml-tree> If I put this code before the tree tag it produces an error. <dtml-call "REQUEST.set('expand_all', 1)"> Zope has encountered an error while publishing this resource. Error Type: KeyError Error Value: branches Troubleshooting Suggestions This resource may be trying to reference a nonexistent object or variable branches. The URL may be incorrect. The parameters passed to this resource may be incorrect. A resource that this resource relies on may be encountering an error. For more detailed information about the error, please refer to the HTML source for this page. If the error persists please contact the site maintainer. Thank you for your patience. Traceback (innermost last): File /Zope/lib/python/ZPublisher/Publish.py, line 214, in publish_module File /Zope/lib/python/ZPublisher/Publish.py, line 179, in publish File /Zope/lib/python/Zope/__init__.py, line 202, in zpublisher_exception_hook (Object: ElementWithAttributes) File /Zope/lib/python/ZPublisher/Publish.py, line 165, in publish File /Zope/lib/python/ZPublisher/mapply.py, line 160, in mapply (Object: index_html) File /Zope/lib/python/ZPublisher/Publish.py, line 102, in call_object (Object: index_html) File /Zope/lib/python/OFS/DTMLMethod.py, line 145, in __call__ (Object: index_html) File /Zope/lib/python/DocumentTemplate/DT_String.py, line 502, in __call__ (Object: index_html) File /Zope/lib/python/TreeDisplay/TreeTag.py, line 154, in render (Object: a tree tag) File /Zope/lib/python/TreeDisplay/TreeTag.py, line 210, in tpRender (Object: ElementWithAttributes) KeyError: (see above) Any ideas? -- Jason Spisak 444(a)hiretechs.com

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ZCatalog
by Tom Deprez 08 Mar '00

08 Mar '00

Hi, I'm cataloging my own created ZClass, the ZClass also has some methods: an external method (like David told, yesterday) : def getParentsEx(self): parentsnames = split(self.absolute_url(),'/')[3:-1] # [3:-1] removes the host info or use something different to split on.. # the -1 removes the last element, i.e. self.id return parentsnames an dtml method getParents_html (just trying if it also works with a dtml-method) : <dtml-in PARENTS> <dtml-if "_['sequence-item'].meta_type=='KBCategory'" > <dtml-var id> </dtml-if> </dtml-in> However I've this problem: 1. When I search on the property title. I get all classes which fulfill the search criteria. However! In the result table, I don't see the values of getParentsEx or getParents_html. (eg like the values of the id of each found class). eg. GetParents Meta html Id Title GetParentsEx type KBItem2 TEST KBItem reree TEST KBItem 2. When I fill in a search criteria in the getParentsEx search-box, I do get the classes back I want. (Except for one, which is also shown, but normally doesn't match the criteria! strange). And the GetParentsEx values are equal to the search criteria (in this case KBCat1) eg. GetParents Meta html Id Title GetParentsEx type KBItem2 TEST KBCat1 KBItem reree TEST KBCat1 KBItem Question: Why aren't the values of GetParentsEx shown in the result table (just like Meta Type is always returned)? What am I doing wrong. How can you show them? Question: Since, I don't see the values of the GetParents_html, I don't know if this works or what I'm doing wrong... Can it work? Thanks in advance, Tom.

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Tree-expand bug!?
by Petr Knapek 08 Mar '00

08 Mar '00

Hi Zopists, I have tried to expand tree and a Zope error has appeared. Below, you can see setting up of expand_all variable together with the beginning of my tree. The collapse_all is working without any problem, the tree collapses when the collapse_all is set up to '1'. The problem is only with the expand_all. Is it Zope bug or something wrong on my side? part of my code <A HREF="<dtml-var URL0>?expand_all=1"><IMG SRC="/p_/pl" ALT="Expand" BORDER="0"> <dtml-tree branches_expr="objectValues(['Folder', 'DTML Document', 'File', 'Image'])" skip_unauthorized=1 sort=is_sort_objects> Zope Error Zope has encountered an error while publishing this resource. Error Type: KeyError Error Value: branches Troubleshooting Suggestions This resource may be trying to reference a nonexistent object or variable branches. The URL may be incorrect. The parameters passed to this resource may be incorrect. A resource that this resource relies on may be encountering an error. For more detailed information about the error, please refer to the HTML source for this page. If the error persists please contact the site maintainer. Thank you for your patience. Traceback (innermost last): File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 214, in publish_module File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 179, in publish File /usr/lib/zope/lib/python/Zope/__init__.py, line 202, in zpublisher_exception_hook (Object: ElementWithAttributes) File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 165, in publish File /usr/lib/zope/lib/python/ZPublisher/mapply.py, line 160, in mapply (Object: is_tree_manage) File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 102, in call_object (Object: is_tree_manage) File /usr/lib/zope/lib/python/OFS/DTMLMethod.py, line 145, in __call__ (Object: is_tree_manage) File /usr/lib/zope/lib/python/DocumentTemplate/DT_String.py, line 502, in __call__ (Object: is_tree_manage) File /usr/lib/zope/lib/python/TreeDisplay/TreeTag.py, line 154, in render (Object: a tree tag) File /usr/lib/zope/lib/python/TreeDisplay/TreeTag.py, line 210, in tpRender (Object: ElementWithAttributes) KeyError: (see above) Thank you, Petr -- Petr Knápek PVT.NET, e-mail: petr.knapek(a)pvt.net, tel:+420-5-41 558 394 PVT a.s. - pvt.net, Veveří 102, 659 10 Brno, Czech Republic

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