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.meddleware.csrf import render_csrf_form_token
  33
  34
  35 SETUP_JINJA_ENVS = {}
  36
  37
  38 def get_jinja_env(template_loader, locale):
  39     """
  40     Set up the Jinja environment,
  41
  42     (In the future we may have another system for providing theming;
  43     for now this is good enough.)
  44     """
  45     mg_globals.thread_scope.translations = get_gettext_translation(locale)
  46
  47     # If we have a jinja environment set up with this locale, just
  48     # return that one.
  49     if locale in SETUP_JINJA_ENVS:
  50         return SETUP_JINJA_ENVS[locale]
  51
  52     # jinja2.StrictUndefined will give exceptions on references
  53     # to undefined/unknown variables in templates.
  54     template_env = jinja2.Environment(
  55         loader=template_loader, autoescape=True,
  56         undefined=jinja2.StrictUndefined,
  57         extensions=[
  58             'jinja2.ext.i18n', 'jinja2.ext.autoescape',
  59             TemplateHookExtension])
  60
  61     template_env.install_gettext_callables(
  62         mg_globals.thread_scope.translations.ugettext,
  63         mg_globals.thread_scope.translations.ungettext)
  64
  65     # All templates will know how to ...
  66     # ... fetch all waiting messages and remove them from the queue
  67     # ... construct a grid of thumbnails or other media
  68     # ... have access to the global and app config
  69     template_env.globals['fetch_messages'] = messages.fetch_messages
  70     template_env.globals['app_config'] = mg_globals.app_config
  71     template_env.globals['global_config'] = mg_globals.global_config
  72     template_env.globals['version'] = _version.__version__
  73
  74     template_env.filters['urlencode'] = url_quote_plus
  75
  76     # allow for hooking up plugin templates
  77     template_env.globals['get_hook_templates'] = get_hook_templates
  78
  79     if exists(locale):
  80         SETUP_JINJA_ENVS[locale] = template_env
  81
  82     return template_env
  83
  84
  85 # We'll store context information here when doing unit tests
  86 TEMPLATE_TEST_CONTEXT = {}
  87
  88
  89 def render_template(request, template_path, context):
  90     """
  91     Render a template with context.
  92
  93     Always inserts the request into the context, so you don't have to.
  94     Also stores the context if we're doing unit tests.  Helpful!
  95     """
  96     template = request.template_env.get_template(
  97         template_path)
  98     context['request'] = request
  99     rendered_csrf_token = render_csrf_form_token(request)
 100     if rendered_csrf_token is not None:
 101         context['csrf_token'] = render_csrf_form_token(request)
 102     rendered = template.render(context)
 103
 104     if common.TESTS_ENABLED:
 105         TEMPLATE_TEST_CONTEXT[template_path] = context
 106
 107     return rendered
 108
 109
 110 def clear_test_template_context():
 111     global TEMPLATE_TEST_CONTEXT
 112     TEMPLATE_TEST_CONTEXT = {}
 113
 114
 115 class TemplateHookExtension(Extension):
 116     """
 117     Easily loop through a bunch of templates from a template hook.
 118
 119     Use:
 120       {% template_hook("comment_extras") %}
 121
 122     ... will include all templates hooked into the comment_extras section.
 123     """
 124
 125     tags = set(["template_hook"])
 126
 127     def parse(self, parser):
 128         includes = []
 129         expr = parser.parse_expression()
 130         lineno = expr.lineno
 131         hook_name = expr.args[0].value
 132
 133         for template_name in get_hook_templates(hook_name):
 134             includes.append(
 135                 parser.parse_import_context(
 136                     Include(Const(template_name), True, False, lineno=lineno),
 137                     True))
 138
 139         return includes