mediagoblin/app.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 import os
  18 import logging
  19 from contextlib import contextmanager
  20
  21 from mediagoblin.routing import get_url_map
  22 from mediagoblin.tools.routing import endpoint_to_controller
  23
  24 from werkzeug.wrappers import Request
  25 from werkzeug.exceptions import HTTPException
  26 from werkzeug.routing import RequestRedirect
  27 from werkzeug.wsgi import SharedDataMiddleware
  28
  29 from mediagoblin import meddleware, __version__
  30 from mediagoblin.db.util import check_db_up_to_date
  31 from mediagoblin.tools import common, session, translate, template
  32 from mediagoblin.tools.response import render_http_exception
  33 from mediagoblin.tools.theme import register_themes
  34 from mediagoblin.tools import request as mg_request
  35 from mediagoblin.media_types.tools import media_type_warning
  36 from mediagoblin.mg_globals import setup_globals
  37 from mediagoblin.init.celery import setup_celery_from_config
  38 from mediagoblin.init.plugins import setup_plugins
  39 from mediagoblin.init import (get_jinja_loader, get_staticdirector,
  40     setup_global_and_app_config, setup_locales, setup_workbench, setup_database,
  41     setup_storage)
  42 from mediagoblin.tools.pluginapi import PluginManager, hook_transform
  43 from mediagoblin.tools.crypto import setup_crypto
  44 from mediagoblin.auth.tools import check_auth_enabled, no_auth_logout
  45
  46 from mediagoblin.tools.transition import DISABLE_GLOBALS
  47
  48
  49 _log = logging.getLogger(__name__)
  50
  51
  52 class Context(object):
  53     """
  54     MediaGoblin context object.
  55
  56     If a web request is being used, a Flask Request object is used
  57     instead, otherwise (celery tasks, etc), attach things to this
  58     object.
  59
  60     Usually appears as "ctx" in utilities as first argument.
  61     """
  62     pass
  63
  64
  65 class MediaGoblinApp(object):
  66     """
  67     WSGI application of MediaGoblin
  68
  69     ... this is the heart of the program!
  70     """
  71     def __init__(self, config_path, setup_celery=True):
  72         """
  73         Initialize the application based on a configuration file.
  74
  75         Arguments:
  76          - config_path: path to the configuration file we're opening.
  77          - setup_celery: whether or not to setup celery during init.
  78            (Note: setting 'celery_setup_elsewhere' also disables
  79            setting up celery.)
  80         """
  81         _log.info("GNU MediaGoblin %s main server starting", __version__)
  82         _log.debug("Using config file %s", config_path)
  83         ##############
  84         # Setup config
  85         ##############
  86
  87         # Open and setup the config
  88         self.global_config, self.app_config = setup_global_and_app_config(config_path)
  89
  90         media_type_warning()
  91
  92         setup_crypto(self.app_config)
  93
  94         ##########################################
  95         # Setup other connections / useful objects
  96         ##########################################
  97
  98         # Setup Session Manager, not needed in celery
  99         self.session_manager = session.SessionManager()
 100
 101         # load all available locales
 102         setup_locales()
 103
 104         # Set up plugins -- need to do this early so that plugins can
 105         # affect startup.
 106         _log.info("Setting up plugins.")
 107         setup_plugins()
 108
 109         # Set up the database
 110         if DISABLE_GLOBALS:
 111             self.db_manager = setup_database(self)
 112         else:
 113             self.db = setup_database(self)
 114
 115         # Quit app if need to run dbupdate
 116         ## NOTE: This is currently commented out due to session errors..
 117         ##  We'd like to re-enable!
 118         # check_db_up_to_date()
 119
 120         # Register themes
 121         self.theme_registry, self.current_theme = register_themes(self.app_config)
 122
 123         # Get the template environment
 124         self.template_loader = get_jinja_loader(
 125             self.app_config.get('local_templates'),
 126             self.current_theme,
 127             PluginManager().get_template_paths()
 128             )
 129
 130         # Check if authentication plugin is enabled and respond accordingly.
 131         self.auth = check_auth_enabled()
 132         if not self.auth:
 133             self.app_config['allow_comments'] = False
 134
 135         # Set up storage systems
 136         self.public_store, self.queue_store = setup_storage()
 137
 138         # set up routing
 139         self.url_map = get_url_map()
 140
 141         # set up staticdirector tool
 142         self.staticdirector = get_staticdirector(self.app_config)
 143
 144         # Setup celery, if appropriate
 145         if setup_celery and not self.app_config.get('celery_setup_elsewhere'):
 146             if os.environ.get('CELERY_ALWAYS_EAGER', 'false').lower() == 'true':
 147                 setup_celery_from_config(
 148                     self.app_config, self.global_config,
 149                     force_celery_always_eager=True)
 150             else:
 151                 setup_celery_from_config(self.app_config, self.global_config)
 152
 153         #######################################################
 154         # Insert appropriate things into mediagoblin.mg_globals
 155         #
 156         # certain properties need to be accessed globally eg from
 157         # validators, etc, which might not access to the request
 158         # object.
 159         #
 160         # Note, we are trying to transition this out;
 161         # run with environment variable DISABLE_GLOBALS=true
 162         # to work on it
 163         #######################################################
 164
 165         if not DISABLE_GLOBALS:
 166             setup_globals(app=self)
 167
 168         # Workbench *currently* only used by celery, so this only
 169         # matters in always eager mode :)
 170         self.workbench_manager = setup_workbench()
 171
 172         # instantiate application meddleware
 173         self.meddleware = [common.import_component(m)(self)
 174                            for m in meddleware.ENABLED_MEDDLEWARE]
 175
 176     @contextmanager
 177     def gen_context(self, ctx=None, **kwargs):
 178         """
 179         Attach contextual information to request, or generate a context object
 180
 181         This avoids global variables; various utilities and contextual
 182         information (current translation, etc) are attached to this
 183         object.
 184         """
 185         if DISABLE_GLOBALS:
 186             with self.db_manager.session_scope() as db:
 187                 yield self._gen_context(db, ctx)
 188         else:
 189             yield self._gen_context(self.db, ctx)
 190
 191     def _gen_context(self, db, ctx, **kwargs):
 192         # Set up context
 193         # --------------
 194
 195         # Is a context provided?
 196         if ctx is None:
 197             ctx = Context()
 198
 199         # Attach utilities
 200         # ----------------
 201
 202         # Attach self as request.app
 203         # Also attach a few utilities from request.app for convenience?
 204         ctx.app = self
 205
 206         ctx.db = db
 207
 208         ctx.staticdirect = self.staticdirector
 209
 210         # Do special things if this is a request
 211         # --------------------------------------
 212         if isinstance(ctx, Request):
 213             ctx = self._request_only_gen_context(ctx)
 214
 215         return ctx
 216
 217     def _request_only_gen_context(self, request):
 218         """
 219         Requests get some extra stuff attached to them that's not relevant
 220         otherwise.
 221         """
 222         # Do we really want to load this via middleware?  Maybe?
 223         request.session = self.session_manager.load_session_from_cookie(request)
 224
 225         request.locale = translate.get_locale_from_request(request)
 226
 227         # This should be moved over for certain, but how to deal with
 228         # request.locale?
 229         request.template_env = template.get_jinja_env(
 230             self, self.template_loader, request.locale)
 231
 232         mg_request.setup_user_in_request(request)
 233
 234         ## Routing / controller loading stuff
 235         request.map_adapter = self.url_map.bind_to_environ(request.environ)
 236
 237         def build_proxy(endpoint, **kw):
 238             try:
 239                 qualified = kw.pop('qualified')
 240             except KeyError:
 241                 qualified = False
 242
 243             return request.map_adapter.build(
 244                     endpoint,
 245                     values=dict(**kw),
 246                     force_external=qualified)
 247
 248         request.urlgen = build_proxy
 249
 250         return request
 251
 252     def call_backend(self, environ, start_response):
 253         request = Request(environ)
 254
 255         # Compatibility with django, use request.args preferrably
 256         request.GET = request.args
 257
 258         # By using fcgi, mediagoblin can run under a base path
 259         # like /mediagoblin/. request.path_info contains the
 260         # path inside mediagoblin. If the something needs the
 261         # full path of the current page, that should include
 262         # the basepath.
 263         # Note: urlgen and routes are fine!
 264         request.full_path = environ["SCRIPT_NAME"] + request.path
 265         # python-routes uses SCRIPT_NAME. So let's use that too.
 266         # The other option would be:
 267         # request.full_path = environ["SCRIPT_URL"]
 268
 269         # Fix up environ for urlgen
 270         # See bug: https://bitbucket.org/bbangert/routes/issue/55/cache_hostinfo-breaks-on-https-off
 271         if environ.get('HTTPS', '').lower() == 'off':
 272             environ.pop('HTTPS')
 273
 274         ## Attach utilities to the request object
 275         with self.gen_context(request) as request:
 276             return self._finish_call_backend(request, environ, start_response)
 277
 278     def _finish_call_backend(self, request, environ, start_response):
 279         # Log user out if authentication_disabled
 280         no_auth_logout(request)
 281
 282         request.controller_name = None
 283         try:
 284             found_rule, url_values = request.map_adapter.match(return_rule=True)
 285             request.matchdict = url_values
 286         except RequestRedirect as response:
 287             # Deal with 301 responses eg due to missing final slash
 288             return response(environ, start_response)
 289         except HTTPException as exc:
 290             # Stop and render exception
 291             return render_http_exception(
 292                 request, exc,
 293                 exc.get_description(environ))(environ, start_response)
 294
 295         controller = endpoint_to_controller(found_rule)
 296         # Make a reference to the controller's symbolic name on the request...
 297         # used for lazy context modification
 298         request.controller_name = found_rule.endpoint
 299
 300         ## TODO: get rid of meddleware, turn it into hooks only
 301         # pass the request through our meddleware classes
 302         try:
 303             for m in self.meddleware:
 304                 response = m.process_request(request, controller)
 305                 if response is not None:
 306                     return response(environ, start_response)
 307         except HTTPException as e:
 308             return render_http_exception(
 309                 request, e,
 310                 e.get_description(environ))(environ, start_response)
 311
 312         request = hook_transform("modify_request", request)
 313
 314         request.start_response = start_response
 315
 316         # get the Http response from the controller
 317         try:
 318             response = controller(request)
 319         except HTTPException as e:
 320             response = render_http_exception(
 321                 request, e, e.get_description(environ))
 322
 323         # pass the response through the meddlewares
 324         try:
 325             for m in self.meddleware[::-1]:
 326                 m.process_response(request, response)
 327         except HTTPException as e:
 328             response = render_http_exception(
 329                 request, e, e.get_description(environ))
 330
 331         self.session_manager.save_session_to_cookie(
 332             request.session,
 333             request, response)
 334
 335         return response(environ, start_response)
 336
 337     def __call__(self, environ, start_response):
 338         ## If more errors happen that look like unclean sessions:
 339         # self.db.check_session_clean()
 340
 341         try:
 342             return self.call_backend(environ, start_response)
 343         finally:
 344             if not DISABLE_GLOBALS:
 345                 # Reset the sql session, so that the next request
 346                 # gets a fresh session
 347                 self.db.reset_after_request()
 348
 349
 350 def paste_app_factory(global_config, **app_config):
 351     configs = app_config['config'].split()
 352     mediagoblin_config = None
 353     for config in configs:
 354         if os.path.exists(config) and os.access(config, os.R_OK):
 355             mediagoblin_config = config
 356             break
 357
 358     if not mediagoblin_config:
 359         raise IOError("Usable mediagoblin config not found.")
 360     del app_config['config']
 361
 362     mgoblin_app = MediaGoblinApp(mediagoblin_config)
 363     mgoblin_app.call_backend = SharedDataMiddleware(mgoblin_app.call_backend,
 364                                                     exports=app_config)
 365     mgoblin_app = hook_transform('wrap_wsgi', mgoblin_app)
 366
 367     return mgoblin_app