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ZPT, a next-generation template technology
by Hamish Lawson 11 Mar '01

11 Mar '01

The Zope Presentation Templates project is underway to develop a next-generation template technology for Zope* that is XHTML-compliant and which makes it easier for designers to work with. However it is hoped to design it in such a way that as much as possible is not specific to Zope, in the belief that the technology is more widely useful and could be adopted by other languages and tools. I'm extending an invitation (in a personal capacity rather than as an official spokesman for the project) to developers from other communities to consider contributing to the design of ZPT to help keep it language-independent, and to consider implementing the approach in their programming language of choice. First of all some background on what I mean by "next-generation". In the beginning programmers wrote program code with embedded HTML. Then technologies like eperl, ASP, JSP and PHP allowed us to reverse this and to embed program code in the HTML. However a school of thought wanted to have greater separation of presentation and logic, and so various template mechanisms were devised that provided just enough programmability to control presentation, but which moved the business logic out elsewhere. One example of this approach is Freemarker: <h1>$customername</h1> <table border="1"> <tr> <td>Date</td> <td>Amount</td> </tr> <list deposits as deposit> <tr> <td>${deposit.date}</td> <td>${deposit.amount}</td> </tr> </list> </table> Instead of custom tags, some other template mechanisms use special markers to designate control structures, but most template mechanisms share the property that their templates are not compliant with XHTML (though the rendered output may be). As such it can be awkward trying to use such template mechanisms with authoring tools that only understand XHTML. The approach that the ZPT project is pursuing is to attach the control-flow, formatting and placeholder directives as attributes of standard XHTML tags. The example above becomes something like: <h1 zpt:insert="customername">Bob Smith</h1> <table border="1"> <tr> <td>Date</td> <td>Amount</td> </tr> <tr zpt:repeat="deposit deposits"> <td zpt:insert="deposit/date">01/02/2001</td> <td zpt:insert="deposit/amount">23.40</td> </tr> </table> This is not only valid XHTML, but (borrowing an idea from Enhydra's XMLC template scheme) the ZPT template scheme allows prototypical content to be used as a proxy for the data to be substituted, so making it easier to work with in an authoring tool. An overview of the ZPT project can be found at http://www.zope.org/Wikis/DevSite/Projects/ZPT/VisionStatement More information on ZPT's attribute language is at http://www.zope.org//Wikis/DevSite/Projects/ZPT/TAL Hamish Lawson * Zope is a leading open-source web application server and content-management framework; it is written in Python. ____________________________________________________________ Do You Yahoo!? Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk or your free @yahoo.ie address at http://mail.yahoo.ie

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dtml-tree: Folder listing from different area(s)
by sbabu＠tnc.org 10 Mar '01

10 Mar '01

Hi, I've a requirement where my application needs to just browse the folder listing using collapsible/expandable trees. dtml-tree is just perfect for this. My application has a DTML document called /myapplication/browse_files.htm I pass a variable to this called BASEURL and that is the root URL from where I want the hierarchy to be displayed. Code is like this: Assume BASEURL has a value http://localhost:8080/mysite1/subsite2/ <dtml-try> <dtml-with "REQUEST.resolve_url(BASEURL)"> <dtml-call "REQUEST.set('currFolderId',id)"> <dtml-tree currFolderId branches_expr="objectValues(['Folder', 'DTML Document','Image','File'])" nowrap=1 sort=id> <IMG SRC="<dtml-var SCRIPT_NAME>/<dtml-var icon>"> <A HREF="<dtml-var absolute_url>"><dtml-var title_or_id></a> </dtml-tree> </dtml-with> <dtml-except> Error here </dtml-try> Now it all works fine initially. When the + sign is clicked to expand a folder, the BASEURL is not passed forward to the resulting display. That causes an error. I'm now passing BASEURL as a session variable, which I think is an ugly solution. My question is: 1. Is there any way I can pass BASEURL to the URLs generated when tree is browsed? 2. Or is there anyway this BASEURL thing can be avoided in the drill-down pages? If it helps, my application is something which will allow users to browse the folder structure and choose a document to make a hyper link from their document. Any pointers, solutions etc will be greatly appreciated. TIA http://vsbabu.csoft.net "The man who smiles when things go wrong has thought of someone to blame it on." --- Jone's Law

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The first site?
by Zopista 10 Mar '01

10 Mar '01

http://www.zopezen.org/#powered is this a world's first? -- Zopista

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Re: [Zope] Image refresh
by Dieter Maurer 10 Mar '01

10 Mar '01

Patrick writes: > And this works fine.Now, I want to change render-image_dtml so that new > images are loaded everytime the page is refreshed by a certain user and so > that the images change automatically if the same page is viewed for say, > 5 minutes. Any ideas? If you want the images chosen randomly (from an image reservoir), then you can use the "whrandom" module, available via the DTML namespace. In any case, the solution depends on how you want to select the images to be displayed during a refresh .... Dieter

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Re: [Zope] "static" includes
by Dieter Maurer 10 Mar '01

10 Mar '01

Oliver Frommel writes: > is there a way to include DTML files in a "static" way, i.e. preserving the > same namespace the including DTML doc has. That is what happens by default, when you include a DTML Method (and not a DTML Document). The DTML Method uses the same namespace as the calling document (unless you explicitely call the method; in this case, it uses namespace and client, you pass in). For details, see URL:http://www.dieter.handshake.de/pyprojects/zope/book/chap3.html Dieter

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Re: [Zope] Cyrillic Characters in URL
by Tim Cook 10 Mar '01

10 Mar '01

Tim Cook wrote: > > Is this part of the Splitter.c problem? I know this is a catalog issue, I do not know why I included it here. :-( -- Tim Cook, President - FreePM,Inc. http://www.FreePM.com Office: (901) 884-4126 ONLINE DEMO: http://www.freepm.org:8080/FreePM

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adding a product
by Ulrich Wisser 10 Mar '01

10 Mar '01

Hello, I installed Yihaw and ran into the problem to add Yihaw items from my own dtml methods. From the HowTo (thanks Søren) I found some hints, but no solution. The problem is, that the items are not directly in the product folder, but instead are inside the YihawChannel ZClass. So here is what I try to do: <dtml-with "news.manage_addProduct['YihawDirectory']"> <dtml-with YihawChannel> <dtml-call "YihawNewsItem_add(_.None, _)"> </dtml-with> </dtml-with> I try to add a YihawNewsItem to my /news (Yihaw-)Folder. So far I was only able to get a security violation. Please find the traceback below. What do I do wrong? Thanks Ulrich Zope Error Zope has encountered an error while publishing this resource. Unauthorized You are not authorized to access YihawNewsItem_add. Traceback (innermost last): File /usr/local/Zope-2.2.5-linux2-x86/lib/python/ZPublisher/Publish.py, line 222, in publish_module File /usr/local/Zope-2.2.5-linux2-x86/lib/python/ZPublisher/Publish.py, line 187, in publish File /usr/local/Zope-2.2.5-linux2-x86/lib/python/ZPublisher/Publish.py, line 171, in publish File /usr/local/Zope-2.2.5-linux2-x86/lib/python/ZPublisher/mapply.py, line 160, in mapply (Object: dtNews) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/ZPublisher/Publish.py, line 112, in call_object (Object: dtNews) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/OFS/DTMLMethod.py, line 172, in __call__ (Object: dtNews) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/DocumentTemplate/DT_String.py, line 528, in __call__ (Object: dtNews) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/DocumentTemplate/DT_With.py, line 146, in render (Object: news.manage_addProduct['YihawDirectory']) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/DocumentTemplate/DT_With.py, line 146, in render (Object: YihawChannel) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/DocumentTemplate/DT_Util.py, line 331, in eval (Object: YihawNewsItem_add(_.None, _)) (Info: YihawNewsItem_add) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/OFS/DTMLMethod.py, line 194, in validate (Object: dtNews) File /usr/local/Zope-2.2.5-linux2-x86/lib/python/AccessControl/SecurityManager.py, line 139, in validate File /usr/local/Zope-2.2.5-linux2-x86/lib/python/AccessControl/ZopeSecurityPolicy.py, line 209, in validate Unauthorized: (see above) -- Searchengine Know How - Webpromotion - Optimization - Internal Search World Wide Web Publisher, Ulrich Wisser, Odensvag 13, S-14571 Norsborg http://www.publisher.de Tel: +46-8-53460905 Fax: +46-8-534 609 06

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How to Defeat Acquisition
by Edmund Goppelt 10 Mar '01

10 Mar '01

I'd like to create a generic index_html for those folders that I haven't gotten around to creating a custom index_html. So, create the default index_html in the root directory and let acquisition do the heavy lifting, right? But, suppose I want to handle the inbetween case where there's custom text I'd like a folder to display, but not enough to justify writing a custom index_html? How can I get my generic index_html to display the contents of a DTML method guts_html if it exists in a folder, *without* acquiring any guts_html from parent folders? How do I defeat acquisition and have my generic index_html *only* look in the namespace of the folder it is called on? Here's the generic index_html I have in my root directory which unfortunately acquires guts_html from folders higher up: <dtml-var standard_html_header> <h2><dtml-var title></h2> <dtml-var folderlist> <dtml-var "PARENTS[0].guts_html" missing=""> <dtml-var standard_html_footer> -- Ed Goppelt

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Re: [Zope] externalmount & zeo voodoo
by Bak ＠ kedai 10 Mar '01

10 Mar '01

> >It sounds like you have two issues: > > 1. you need better write performance. this can be done by minimizing >conflicterrors. > > 2. your zope is apparently unstable (which may have nothing to do with the >number of conflict errors you're getting) > >Issue #1 is addressable by new application level conflict resolution code >added to ZODB which should be out in 2.3.1b2 (the release of which is >currently pending on new catalog code to pass all of its unit and >performance tests). You can read about it at >http://www.zope.org/Members/jim/ZODB/ApplicationLevelConflictResolution. >Other complementary ways to deal with this are intelligent coding (don't do >writes when you don't have to, don't modify objects that you don't need to), >appropriate data structuring (use lots of subfolders in objectmanagers, use >other partitioned data structures like BTrees when possible), and can you elaborate more on using lots of subfolders and BTrees knowing >when to punt and use a relational database that uses locking instead of >optimistic concurrency like the ZODB. There's no cookie-cutter solution... >hopefully when folks get used to the new app-level conflict resolution, >they'll make use of it in their products to increase write performance and >minimize conflicts. I'm going to try this for the next sessioning release. >The current generation of Zope products know nothing about conflict >resolution, so it'll probably take a while for it to become mainstream. > >Issue #2 is separate... you should turn on request logging (see the -M i see this happening when i enabled poll. when there's a lot of users clicking, zope restarts. the restarts stop when i took out poll. otherwise, zope has been solid like a rock >switch in z2.py) and use the script at >http://www.zope.org/Members/mcdonc/HowTos/DEBUG-LOG (ignore the bit at the >top about inserting stuff into z2.py, it's been superseded by the -M switch) >to figure out what requests aren't returning from a method call. With that >info, you should hopefully be able to establish a pattern and isolate the >problem. i'll try and enable poll and start zope with -M thanks _______________________________________________ >Zope maillist - Zope(a)zope.org >http://lists.zope.org/mailman/listinfo/zope >** No cross posts or HTML encoding! ** >(Related lists - > http://lists.zope.org/mailman/listinfo/zope-announce > http://lists.zope.org/mailman/listinfo/zope-dev ) >

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probably stupid: changing zstylesheet properties through dtml
by Danny William Adair 10 Mar '01

10 Mar '01

How can I programmatically change A ZStyleSheet attribute (ZSSAttr) through dtml??? <dtml-with css_content> <dtml-with Body> <dtml-call "background.manage_changeProperties({'value' : new_bg})"> </dtml-with> </dtml-with> won't do, it gets me an authentication request (whatever my role), telling me I am not allowed to access "changeProperties". It's not a ZClass, so there is no propertysheet I would have to define, is that right? Through the management screen, everything works fine, but I want to change only a few attributes from a _dtml method_, and I simply don't know how to do it. I've given the method every available proxy role, and still. I really believe that my problem is not ZStyleSheet-specific, but could anyone out there who has successfully done _this_ tell me how to do it? Thx in advance, Danny

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