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 get_hook_templates, hook_transform
  31 from mediagoblin.tools.timesince import timesince
  32 from mediagoblin.meddleware.csrf import render_csrf_form_token
  33
  34
  35
  36 SETUP_JINJA_ENVS = {}
  37
  38
  39 def get_jinja_env(template_loader, locale):
  40     """
  41     Set up the Jinja environment,
  42
  43     (In the future we may have another system for providing theming;
  44     for now this is good enough.)
  45     """
  46     set_thread_locale(locale)
  47
  48     # If we have a jinja environment set up with this locale, just
  49     # return that one.
  50     if locale in SETUP_JINJA_ENVS:
  51         return SETUP_JINJA_ENVS[locale]
  52
  53     # jinja2.StrictUndefined will give exceptions on references
  54     # to undefined/unknown variables in templates.
  55     template_env = jinja2.Environment(
  56         loader=template_loader, autoescape=True,
  57         undefined=jinja2.StrictUndefined,
  58         extensions=[
  59             'jinja2.ext.i18n', 'jinja2.ext.autoescape',
  60             TemplateHookExtension])
  61
  62     template_env.install_gettext_callables(
  63         mg_globals.thread_scope.translations.ugettext,
  64         mg_globals.thread_scope.translations.ungettext)
  65
  66     # All templates will know how to ...
  67     # ... fetch all waiting messages and remove them from the queue
  68     # ... construct a grid of thumbnails or other media
  69     # ... have access to the global and app config
  70     template_env.globals['fetch_messages'] = messages.fetch_messages
  71     template_env.globals['app_config'] = mg_globals.app_config
  72     template_env.globals['global_config'] = mg_globals.global_config
  73     template_env.globals['version'] = _version.__version__
  74
  75     template_env.filters['urlencode'] = url_quote_plus
  76
  77     # add human readable fuzzy date time
  78     template_env.globals['timesince'] = timesince
  79
  80     # allow for hooking up plugin templates
  81     template_env.globals['get_hook_templates'] = get_hook_templates
  82
  83     template_env.globals = hook_transform(
  84         'template_global_context', template_env.globals)
  85
  86     if exists(locale):
  87         SETUP_JINJA_ENVS[locale] = template_env
  88
  89     return template_env
  90
  91
  92 # We'll store context information here when doing unit tests
  93 TEMPLATE_TEST_CONTEXT = {}
  94
  95
  96 def render_template(request, template_path, context):
  97     """
  98     Render a template with context.
  99
 100     Always inserts the request into the context, so you don't have to.
 101     Also stores the context if we're doing unit tests.  Helpful!
 102     """
 103     template = request.template_env.get_template(
 104         template_path)
 105     context['request'] = request
 106     rendered_csrf_token = render_csrf_form_token(request)
 107     if rendered_csrf_token is not None:
 108         context['csrf_token'] = render_csrf_form_token(request)
 109
 110     # allow plugins to do things to the context
 111     if request.controller_name:
 112         context = hook_transform(
 113             (request.controller_name, template_path),
 114             context)
 115
 116     # More evil: allow plugins to possibly do something to the context
 117     # in every request ever with access to the request and other
 118     # variables.  Note: this is slower than using
 119     # template_global_context
 120     context = hook_transform(
 121         'template_context_prerender', context)
 122
 123     rendered = template.render(context)
 124
 125     if common.TESTS_ENABLED:
 126         TEMPLATE_TEST_CONTEXT[template_path] = context
 127
 128     return rendered
 129
 130
 131 def clear_test_template_context():
 132     global TEMPLATE_TEST_CONTEXT
 133     TEMPLATE_TEST_CONTEXT = {}
 134
 135
 136 class TemplateHookExtension(Extension):
 137     """
 138     Easily loop through a bunch of templates from a template hook.
 139
 140     Use:
 141       {% template_hook("comment_extras") %}
 142
 143     ... will include all templates hooked into the comment_extras section.
 144     """
 145
 146     tags = set(["template_hook"])
 147
 148     def parse(self, parser):
 149         includes = []
 150         expr = parser.parse_expression()
 151         lineno = expr.lineno
 152         hook_name = expr.args[0].value
 153
 154         for template_name in get_hook_templates(hook_name):
 155             includes.append(
 156                 parser.parse_import_context(
 157                     Include(Const(template_name), True, False, lineno=lineno),
 158                     True))
 159
 160         return includes