mediagoblin/tools/template.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 from math import ceil
  18
  19 import jinja2
  20 from jinja2.ext import Extension
  21 from jinja2.nodes import Include, Const
  22
  23 from babel.localedata import exists
  24 from werkzeug.urls import url_quote_plus
  25
  26 from mediagoblin import mg_globals
  27 from mediagoblin import messages
  28 from mediagoblin import _version
  29 from mediagoblin.tools import common
  30 from mediagoblin.tools.translate import get_gettext_translation
  31 from mediagoblin.tools.pluginapi import get_hook_templates
  32 from mediagoblin.tools.timesince import timesince
  33 from mediagoblin.meddleware.csrf import render_csrf_form_token
  34
  35
  36
  37 SETUP_JINJA_ENVS = {}
  38
  39
  40 def get_jinja_env(template_loader, locale):
  41     """
  42     Set up the Jinja environment,
  43
  44     (In the future we may have another system for providing theming;
  45     for now this is good enough.)
  46     """
  47     mg_globals.thread_scope.translations = get_gettext_translation(locale)
  48
  49     # If we have a jinja environment set up with this locale, just
  50     # return that one.
  51     if locale in SETUP_JINJA_ENVS:
  52         return SETUP_JINJA_ENVS[locale]
  53
  54     # jinja2.StrictUndefined will give exceptions on references
  55     # to undefined/unknown variables in templates.
  56     template_env = jinja2.Environment(
  57         loader=template_loader, autoescape=True,
  58         undefined=jinja2.StrictUndefined,
  59         extensions=[
  60             'jinja2.ext.i18n', 'jinja2.ext.autoescape',
  61             TemplateHookExtension])
  62
  63     template_env.install_gettext_callables(
  64         mg_globals.thread_scope.translations.ugettext,
  65         mg_globals.thread_scope.translations.ungettext)
  66
  67     # All templates will know how to ...
  68     # ... fetch all waiting messages and remove them from the queue
  69     # ... construct a grid of thumbnails or other media
  70     # ... have access to the global and app config
  71     template_env.globals['fetch_messages'] = messages.fetch_messages
  72     template_env.globals['app_config'] = mg_globals.app_config
  73     template_env.globals['global_config'] = mg_globals.global_config
  74     template_env.globals['version'] = _version.__version__
  75
  76     template_env.filters['urlencode'] = url_quote_plus
  77
  78     # add human readable fuzzy date time
  79     template_env.globals['timesince'] = timesince
  80
  81     # allow for hooking up plugin templates
  82     template_env.globals['get_hook_templates'] = get_hook_templates
  83
  84     if exists(locale):
  85         SETUP_JINJA_ENVS[locale] = template_env
  86
  87     return template_env
  88
  89
  90 # We'll store context information here when doing unit tests
  91 TEMPLATE_TEST_CONTEXT = {}
  92
  93
  94 def render_template(request, template_path, context):
  95     """
  96     Render a template with context.
  97
  98     Always inserts the request into the context, so you don't have to.
  99     Also stores the context if we're doing unit tests.  Helpful!
 100     """
 101     template = request.template_env.get_template(
 102         template_path)
 103     context['request'] = request
 104     rendered_csrf_token = render_csrf_form_token(request)
 105     if rendered_csrf_token is not None:
 106         context['csrf_token'] = render_csrf_form_token(request)
 107     rendered = template.render(context)
 108
 109     if common.TESTS_ENABLED:
 110         TEMPLATE_TEST_CONTEXT[template_path] = context
 111
 112     return rendered
 113
 114
 115 def clear_test_template_context():
 116     global TEMPLATE_TEST_CONTEXT
 117     TEMPLATE_TEST_CONTEXT = {}
 118
 119
 120 class TemplateHookExtension(Extension):
 121     """
 122     Easily loop through a bunch of templates from a template hook.
 123
 124     Use:
 125       {% template_hook("comment_extras") %}
 126
 127     ... will include all templates hooked into the comment_extras section.
 128     """
 129
 130     tags = set(["template_hook"])
 131
 132     def parse(self, parser):
 133         includes = []
 134         expr = parser.parse_expression()
 135         lineno = expr.lineno
 136         hook_name = expr.args[0].value
 137
 138         for template_name in get_hook_templates(hook_name):
 139             includes.append(
 140                 parser.parse_import_context(
 141                     Include(Const(template_name), True, False, lineno=lineno),
 142                     True))
 143
 144         return includes