[Zope] Messing with the namespaces stack [Was: (no subject)]

[Shane Hathaway]

Jim Hebert wrote:
> OK, I am just going to go ahead and spill the rest of what swirled around
> in my head about zope when I threw up this vistasource.com site, in the
> hopes that I'll either get another ego stroke (*grin*) or some more
> insights as to the reason why things are done the way they are (ie, not
> the way I do 'em!). This is probably going to be long, please forgive me
> for going from newly subscribed to thinks-he-can-write-a-howto overnight!
> =)

Ha ha! I like your enthusiasm, Jim.

> I am bucking a trend, I am starting to realize. Big time! The assumption
> seems to be that any given page will build itself, it will suck in
> standard_html_header and standard_html_footer, and compose itself of
> whatever else in between those things. DTML Document is the base unit of a
> page.
> 
> Partially because I was planning at the time to build an over-simplified
> front end for our system, I wanted people to be able to upload simple,
> stupid chunks of "content" html and not have to do things like put
> <dtml-var standard_html_header> at the top and ..._footer at the bottom.
> Any lame wysiwyg editor that had save-to-ftp could then push up a 'body
> file' into the right folder, and I could get writers writing without
> learning zope.

It's a great idea but I've had some thoughts on this myself.  I think
the approach I would take is to create a ZClass.  Content authors would
create instances of this ZClass and would not have to use
standard-html-header nor any other DTML if they don't want to.  The
ZClass would perform a simple transformation of the content before
presenting it on the Web, such as adding standard_html_header/footer
and including the title and date.

> I also started to really groove on the idea of Object Oriented precepts
> for my pages, and having to explicitly "#include" peices like the common
> stuff offended those sensibilities. I wanted "objects" that had both
> "data" and "code" as its members, in a nice little bundle.
>
> So, I made the decision that my atomic unit of what constitutes a "page"
> on my server is a Folder object. This lets me collect everything
> specific to a page, images that are only used there, methods that are
> only used there, etc, in a tidy little bundle. So here's my scheme:
> 
> I think of /index_html, a DTML Method, as if it were a member function of
> an object. It might as well be named "render_this_folder_as_a_page." So,
> it looks like (oversimplifying:)
> 
> <dtml-with images>
> <dtml-with "PARENTS[0]">
> <dtml-var standard_html_header>
> <table><tr><td>
> <dtml-var menu>
> </td><td>
> <dtml-var body>
> </td></tr></table>
> <dtml-var stnadard_html_footer>
> </dtml-with>
> </dtml-with>
> 
> So, now, in each folder I just put a dtml method called body. When you
> visit /about, index_html gets acquired, but since it's a dtml method, the
> /about folder remains the first place to look for other stuff, so body
> gets located in /about. If I want to override the menu code, I also stick
> another object in there called menu, but by default my toplevel menu code
> works for all the subfolders. In some perverse sense, sub-pages
> conceptually are sub-classes of higher up pages, which inherit some things
> (index_html for instance) things and override things (/body, nearly
> always, and sometimes other things).

I think you'll have more flexibility if you make ZClasses a major part
of your solution. When the time comes, you'll be able to make
fundamental changes more easily. Have you learned about property sheets
yet?  They are the key to success with ZClasses.

> If I repeitively built $header + $menu + some content + footer over and
> over again in page after page, I couldn't radically redesign my site (for
> instance, pulling in body and sticking an advertisement between every 3rd
> paragraph) without touching every page. But in the model that I use, the
> one true index_html method is free to suck body in, do crazy
> post-processing to it, and then send that out.
>
> And, of course, index_html itself can be overridden for sub-trees of the
> site, if need be.
> 
> And, I can also come up with different renderers, I suppose. Untested
> might be the idea that I could put /alt_renderer as a DTML Method at the
> top level, then visit /about/alt_renderer and invoke that method in the
> /about context. So by separating content from presentation, I can plug my
> content into lots of things simultaneously. Presumably.

Also remember you can play tricks with acquisition.  If you have a
"default" style and a "lowres" style, you can set up your directories
like this:

/home
  /lowres
  /content

"lowres" and "content" are both children of "home".  The default style
elements are in home.  When the user browses to
/home/content/index_html, they get the default style.  When the user
visits /home/lowres/content/index_html, they get the lowres style.

> The only thing that has bummed me out about this strategy is that I feel
> like that every time I use a 3rd party product I end up working up hill:
> it usually expects to be able to write out a DTML Method or Document that
> says
> 
> <dtml-var standard_html_header>
> app-specific-logic-here
> <dtml-var standard_html_footer>
>
> and have gotten it all. Adding a "Search Interface" is a typical example
> of this. When I can, I hack around this and migrate
> "app-specific-logic-here" into SomeFolderName/body. But for products which
> manufacture pages on an ongoing basis, e.g. FlexFaq/Knowledgebase,
> this is less of an option, and points more towards me hacking the package
> code itself.
> 
> I don't honestly expect that what I invented in the middle of the night 7
> days before the VistaSource launch to revolutionize how everyone builds
> pages (like I said, I actually suspect that these hacks that I invented
> have some major drawback that you guys will help clue me into, though,
> hehehe, I haven't been dissauded by the search drawback..), but
> perhaps someone will have suggestions on how I can make my style "play
> nicer" with all these products, too.
> 
> Sorry so long. If this was illustrative to anyone for seeing how
> unbelievably, scream it down the halls, wake your mom up in the middle of
> the night to tell her, very very cool Zope is, then it was worth it. =)
> Because Zope is quite simply the coolest damn thing I have ever worked on,
> bar none. I would love to bump into Jim Fulton at a show sometime, because
> I think I like the way his mind works!! =)

Jim and the rest of the Zope community have created a lot of mechanisms
in Zope and it's not easy to grasp all of them.  But learning each
concept is a fun experience.  And they all tie together.

Zope is like a collection of Legos (TM): you're given a bunch of blocks
and some instructions on how to build some specific models, but
encouraged to explore putting them together in new ways.  Have you
heard of the Lego Machine Gun?  :-)

Shane