[Web-SIG] A trivial template API counter-proposal
ianb at colorstudy.com
Sun Feb 5 21:36:40 CET 2006
Phillip J. Eby wrote:
>>This topic started with Buffet, the de-facto standard templating API for
>>CherryPy. Buffet is just about textual templating, which is a good
>>thing. That's why it's very simple, and is thus actually being used.
> Which is precisely why we don't need to rush into blessing it as some kind
> of web standard, when it doesn't have anything to do with the "web", as far
> as I can tell. If I needed a plugin for pure text or XML templating (as
> opposed to *web application* templates), or I were creating a pure text or
> XML output generator, I would absolutely use the TG/Buffet API, no
> question. It is 100% the right tool for the job, and the de facto standard
> as well.
> But I'm also 100% positive that it is *not* suitable to be declared a
> Python *web* standard by itself: it's not about the web at all. The web
> just happens to be where it's being used at the moment, and only in
> frameworks where the use cases slot neatly together with it. Heck, just
> look at the API documentation and see if you can find the word "web" or
> even "request" mentioned on the page:
It is not a complete spec that fits many use cases at this time. It
won't be sufficient for TG either before long -- Kevin has already said
that he'd like a find_template function somewhere in there.
Because the spec suggests that templates are given module-like names
coinciding with the package of the consuming software, it is hard to use
in any way where the templates themselves are taken from arbitrary
locations. It doesn't actually specify how the names are interpreted or
how the templates are found, but all the implementations so far use
pkg_resources and load templates in a way that makes it difficult to
load arbitrary files.
This probably seemed sensible since the first couple languages -- Kid
and Cheetah -- compile to Python modules. But while it seems sensible,
Python modules are far more difficult to work with than simpler
metaphors for a compiled template -- you get import hooks, rather
complicated recompilation steps, and add one more thing to the already
complex task of managing sys.path.
So no, this isn't sufficient now. I think very minor fixes could
improve it -- for instance, allow template_filename as an argument
instead of only template_name. Then at least simple template filling
would be handled well (e.g., enough for Paste Script), though it is
unlikely (with only those specs) that templates will handle including
other templates very well, as there's not even sufficient information
given for the template language to figure out the programmer's intent.
Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org
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