Malcolm Tredinnick wrote:
> On Tue, 2007-06-12 at 05:44 -0400, Andrew R wrote:
>> I have to admit, though, that I think adding a custom filter should be as
>> simple
>> as this code alone:
>>
>>> from django.template import Library
>>>
>>> register = Library()
>>>
>>> @register.filter
>>> def javadoc_filter(value, arg):
>>> return "whatever"
>>>
>> I think part of my confusion was that my subconscious thinking was "my filter
>> code has been imported (I can see the .pyc) so I know python has seen it, and
>> therefore the filter is registered with the library, so I should be able to
>> use
>> it.".
>
> ...
>
> If you come up with a patch to make filter registration remember the
> path to the file so that the "load" template tag can find it later, we'd
> certainly consider it.
Malcolm - you mentioned a patch to support this - I've provided one below.
With the patch, I can write a filter like this in my main program (or anywhere):
def filter_rst_h1(value, arg='-'):
"Write a single underline under the text"
line=arg * len(value)
return "%s\n%s" % (value, line)
To use this filter, all I need is this:
from django.template import BuiltinLibrary # <-- NEW!
# set up extra library of routines for later use...
library = BuiltinLibrary()
library.filter('filter_rst_h1', filter_rst_h1)
Then the template uses the filter like this:
{{subtitle|rst_format_h1}}
Below is the patch - 4 new lines of code - to enable BuiltinLibrary:
---->8---->8---->8----
$ svn diff django/template
Index: django/template/__init__.py
===================================================================
--- django/template/__init__.py (revision 5572)
+++ django/template/__init__.py (working copy)
@@ -912,6 +912,11 @@
return func
return dec
+class BuiltinLibrary(Library):
+ def __init__(self, *args, **kwargs):
+ Library.__init__(self, *args, **kwargs)
+ builtins.append(self)
+
def get_library(module_name):
lib = libraries.get(module_name, None)
if not lib:
---->8---->8---->8----
Here is a complete, standalone example program:
---->8---->8---->8----
"""Proof of concept for on-the-fly, standalone DJango filter code.
Problem: in some of my work I use the nifty DJango template code
for documentation generation in standalone code - i.e. I generate
documentation of some form without using any web app/infrastructure
at all.
DJango can works fine sans-web so long as you set it up correctly
and you don't use custom filters or tags.
Actually, thats not 100% true. You *can* use custom filters and tags,
but it takes a bit of magic that I didn't think should be necessary.
The challenge was to submit a patch to the DJango code, but to do
that I need a small demo app that proves the new work..
Objective: Render a template, completely standalone, using custom filters
and tags, in a "Django-compliant" way with minimal code changes to DJango.
Specifically, this demo renders some restructured text using filters
to generate underlines and header formatting.
Remember: the changes to DJango mustn't break any existing behavior!
A.E. June 2007
"""
import sys, re, os, os.path
try: import django
except ImportError, e:
sys.stderr.write("DJango not installed\n")
sys.exit(1)
template_content="""{{ title|rst_format_title:"=" }}
{{author|rst_format_author}}
{% rst_doc_date %}
{{subtitle|rst_format_h1}}
{{para}}
"""
def do_filter_demo():
"""Render a template from a string using our local filter.
This will render something like:
>>>
===============
Filtered Demo
===============
:Author: A. Roark
:Date: 2007-06-30 21:45:40.205000
Simple restructured text demo
-----------------------------
This uses builtin filters for formatting text
<<<
"""
# Render the template here - note that no special imports/code needed.
t=Template(template_content)
context=Context({
'title': 'Filtered Demo',
'author': 'A. Roark',
'subtitle': 'Simple restructured text demo',
'para': 'This uses builtin filters for formatting text',
})
out=t.render(context)
print "\nDjango Custom Filter Demo:\n>>>\n%s\n<<<\n" % out
#
# --- Define some filters here ---
#
def filter_rst_h1(value, arg='-'):
"Write a single underline under the text"
line=arg * len(value)
return "%s\n%s" % (value, line)
def filter_rst_title(value, arg='-'):
"Add a line before and after the text"
line=arg * (2+len(value))
return "%s\n %s \n%s" % (line, value, line)
def filter_rst_author(value, arg=None):
return ":Author: %s" %value
#
# --- A simple tag ---
#
def tag_rst_doc_date(parser, token):
# A "real" tag should be much more than this -
# I'm amazed this works as-is, but its ok for a demo.
# For real details, see:
#
http://www.djangoproject.com/documentation/templates_python/#writing-the-compilation-function
import datetime
return ":Date: %s" % datetime.datetime.now()
#
# --- Main code ---
#
if __name__ == "__main__":
# In a standalone app, do this first, before other imports
from django.conf import settings
settings.configure(
# for debug:
# DEBUG=True, TEMPLATE_DEBUG=True,
# for template files, something like...
# TEMPLATE_DIRS=(root_dir, os.path.join(root_dir, 'ref'))
)
from django.template import Template, Context, BuiltinLibrary
# set up extra library of routines for later use...
custom_library = BuiltinLibrary()
custom_library.filter('rst_format_title', filter_rst_title)
custom_library.filter('rst_format_h1', filter_rst_h1)
custom_library.filter('rst_format_author', filter_rst_author)
custom_library.tag( 'rst_doc_date', tag_rst_doc_date)
do_filter_demo()
---->8---->8---->8----
WDYT?
Andrew
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Django users" group.
To post to this group, send email to django-users@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/django-users?hl=en
-~----------~----~----~----~------~----~------~--~---
