django/template/loaders/app_directories.py

   1 """
   2 Wrapper for loading templates from "template" directories in INSTALLED_APPS
   3 packages.
   4 """
   5
   6 import os
   7
   8 from django.conf import settings
   9 from django.core.exceptions import ImproperlyConfigured
  10 from django.template import TemplateDoesNotExist
  11 from django.utils._os import safe_join
  12
  13 # At compile time, cache the directories to search.
  14 app_template_dirs = []
  15 for app in settings.INSTALLED_APPS:
  16     i = app.rfind('.')
  17     if i == -1:
  18         m, a = app, None
  19     else:
  20         m, a = app[:i], app[i+1:]
  21     try:
  22         if a is None:
  23             mod = __import__(m, {}, {}, [])
  24         else:
  25             mod = getattr(__import__(m, {}, {}, [a]), a)
  26     except ImportError, e:
  27         raise ImproperlyConfigured, 'ImportError %s: %s' % (app, e.args[0])
  28     template_dir = os.path.join(os.path.dirname(mod.__file__), 'templates')
  29     if os.path.isdir(template_dir):
  30         app_template_dirs.append(template_dir)
  31
  32 # It won't change, so convert it to a tuple to save memory.
  33 app_template_dirs = tuple(app_template_dirs)
  34
  35 def get_template_sources(template_name, template_dirs=None):
  36     """
  37     Returns the absolute paths to "template_name", when appended to each
  38     directory in "template_dirs". Any paths that don't lie inside one of the
  39     template dirs are excluded from the result set, for security reasons.
  40     """
  41     if not template_dirs:
  42         template_dirs = app_template_dirs
  43     for template_dir in template_dirs:
  44         try:
  45             yield safe_join(template_dir, template_name)
  46         except UnicodeDecodeError:
  47             # The template dir name was a bytestring that wasn't valid UTF-8.
  48             raise
  49         except ValueError:
  50             # The joined path was located outside of template_dir.
  51             pass
  52
  53 def load_template_source(template_name, template_dirs=None):
  54     for filepath in get_template_sources(template_name, template_dirs):
  55         try:
  56             return (open(filepath).read().decode(settings.FILE_CHARSET), filepath)
  57         except IOError:
  58             pass
  59     raise TemplateDoesNotExist, template_name
  60 load_template_source.is_usable = True