Django snippets

#!/usr/bin/python2.4

"""JsCompiler Django template filter."""

__author__ = 'jeremydw@gmail.com (Jeremy Weinstein)'

import base64
import urllib
from django.core.cache import cache
from django import template
from django.utils import simplejson

COMPILER_SERVICE = 'http://closure-compiler.appspot.com/compile'

register = template.Library()


@register.filter
def jscomp(js):
  """Returns compiled Javascript from raw source.

  Makes a remote call to Closure Compiler service to compile filter contents.
  Args:
    js: The raw Javascript source.
  Returns:
    Compiled Javascript.
  """
  js_id = base64.urlsafe_b64encode(js).strip()
  compiled_code = cache.get(js_id)
  if not compiled_code:
    params = urllib.urlencode({
        'output_format': 'json',
        'output_info': 'compiled_code',
        'compilation_level': 'ADVANCED_OPTIMIZATIONS',
        'warning_level': 'verbose',
        'use_closure_library': 'true',
        'js_code': js,
    })
    try:
      response = urllib.urlopen(COMPILER_SERVICE, params).read()
    except IOError:
      raise Exception(
          'Failed to download from: %s?%s', (COMPILER_SERVICE, params))
    compiled_code = simplejson.loads(response)['compiledCode']
    cache.set(js_id, compiled_code)
  return compiled_code