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     template_env.globals['auth'] = mg_globals.app.auth
  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     template_env.globals = hook_transform(
  85         'template_global_context', template_env.globals)
  86
  87     if exists(locale):
  88         SETUP_JINJA_ENVS[locale] = template_env
  89
  90     return template_env
  91
  92
  93 # We'll store context information here when doing unit tests
  94 TEMPLATE_TEST_CONTEXT = {}
  95
  96
  97 def render_template(request, template_path, context):
  98     """
  99     Render a template with context.
 100
 101     Always inserts the request into the context, so you don't have to.
 102     Also stores the context if we're doing unit tests.  Helpful!
 103     """
 104     template = request.template_env.get_template(
 105         template_path)
 106     context['request'] = request
 107     rendered_csrf_token = render_csrf_form_token(request)
 108     if rendered_csrf_token is not None:
 109         context['csrf_token'] = render_csrf_form_token(request)
 110
 111     # allow plugins to do things to the context
 112     if request.controller_name:
 113         context = hook_transform(
 114             (request.controller_name, template_path),
 115             context)
 116
 117     # More evil: allow plugins to possibly do something to the context
 118     # in every request ever with access to the request and other
 119     # variables.  Note: this is slower than using
 120     # template_global_context
 121     context = hook_transform(
 122         'template_context_prerender', context)
 123
 124     rendered = template.render(context)
 125
 126     if common.TESTS_ENABLED:
 127         TEMPLATE_TEST_CONTEXT[template_path] = context
 128
 129     return rendered
 130
 131
 132 def clear_test_template_context():
 133     global TEMPLATE_TEST_CONTEXT
 134     TEMPLATE_TEST_CONTEXT = {}
 135
 136
 137 class TemplateHookExtension(Extension):
 138     """
 139     Easily loop through a bunch of templates from a template hook.
 140
 141     Use:
 142       {% template_hook("comment_extras") %}
 143
 144     ... will include all templates hooked into the comment_extras section.
 145     """
 146
 147     tags = set(["template_hook"])
 148
 149     def parse(self, parser):
 150         includes = []
 151         expr = parser.parse_expression()
 152         lineno = expr.lineno
 153         hook_name = expr.args[0].value
 154
 155         for template_name in get_hook_templates(hook_name):
 156             includes.append(
 157                 parser.parse_import_context(
 158                     Include(Const(template_name), True, False, lineno=lineno),
 159                     True))
 160
 161         return includes