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
  18 import jinja2
  19 from jinja2.ext import Extension
  20 from jinja2.nodes import Include, Const
  21
  22 from babel.localedata import exists
  23 from werkzeug.urls import url_quote_plus
  24
  25 from mediagoblin import mg_globals
  26 from mediagoblin import messages
  27 from mediagoblin import _version
  28 from mediagoblin.tools import common
  29 from mediagoblin.tools.translate import set_thread_locale
  30 from mediagoblin.tools.pluginapi import (
  31     get_hook_templates, hook_transform)
  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     set_thread_locale(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
 108     # allow plugins to do things to the context
 109     context = hook_transform(
 110         (request.controller_name, template_path),
 111         context)
 112
 113     rendered = template.render(context)
 114
 115     if common.TESTS_ENABLED:
 116         TEMPLATE_TEST_CONTEXT[template_path] = context
 117
 118     return rendered
 119
 120
 121 def clear_test_template_context():
 122     global TEMPLATE_TEST_CONTEXT
 123     TEMPLATE_TEST_CONTEXT = {}
 124
 125
 126 class TemplateHookExtension(Extension):
 127     """
 128     Easily loop through a bunch of templates from a template hook.
 129
 130     Use:
 131       {% template_hook("comment_extras") %}
 132
 133     ... will include all templates hooked into the comment_extras section.
 134     """
 135
 136     tags = set(["template_hook"])
 137
 138     def parse(self, parser):
 139         includes = []
 140         expr = parser.parse_expression()
 141         lineno = expr.lineno
 142         hook_name = expr.args[0].value
 143
 144         for template_name in get_hook_templates(hook_name):
 145             includes.append(
 146                 parser.parse_import_context(
 147                     Include(Const(template_name), True, False, lineno=lineno),
 148                     True))
 149
 150         return includes