Will Kahn-Greene 05e007c1db Rework plugin infrastructure to nix side-effects
This reworks the plugin infrastructure so as to remove module-loading
side-effects which were making things a pain in the ass to test.

With the new system, there's no auto-registering meta class. Instead
plugins do whatever they want and then specify a hooks dict that maps
hook names to callables for the things they're tying into. The most
common one (and the only one we've implemented so far) is "setup".

This also simplifies the sampleplugin a little by moving the code
to __init__.py.
2012-07-17 21:02:12 -04:00

236 lines
8.8 KiB
Python

# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import os
import urllib
import logging
import routes
from webob import Request, exc
from mediagoblin import routing, meddleware, __version__
from mediagoblin.tools import common, translate, template
from mediagoblin.tools.response import render_404
from mediagoblin.tools.theme import register_themes
from mediagoblin.tools import request as mg_request
from mediagoblin.mg_globals import setup_globals
from mediagoblin.init.celery import setup_celery_from_config
from mediagoblin.init.plugins import setup_plugins
from mediagoblin.init import (get_jinja_loader, get_staticdirector,
setup_global_and_app_config, setup_workbench, setup_database,
setup_storage, setup_beaker_cache)
from mediagoblin.tools.pluginapi import PluginManager
_log = logging.getLogger(__name__)
class MediaGoblinApp(object):
"""
WSGI application of MediaGoblin
... this is the heart of the program!
"""
def __init__(self, config_path, setup_celery=True):
"""
Initialize the application based on a configuration file.
Arguments:
- config_path: path to the configuration file we're opening.
- setup_celery: whether or not to setup celery during init.
(Note: setting 'celery_setup_elsewhere' also disables
setting up celery.)
"""
_log.info("GNU MediaGoblin %s main server starting", __version__)
_log.debug("Using config file %s", config_path)
##############
# Setup config
##############
# Open and setup the config
global_config, app_config = setup_global_and_app_config(config_path)
##########################################
# Setup other connections / useful objects
##########################################
# Set up plugins -- need to do this early so that plugins can
# affect startup.
_log.info("Setting up plugins.")
setup_plugins()
# Set up the database
self.connection, self.db = setup_database()
# Register themes
self.theme_registry, self.current_theme = register_themes(app_config)
# Get the template environment
self.template_loader = get_jinja_loader(
app_config.get('local_templates'),
self.current_theme,
PluginManager().get_template_paths()
)
# Set up storage systems
self.public_store, self.queue_store = setup_storage()
# set up routing
self.routing = routing.get_mapper(PluginManager().get_routes())
# set up staticdirector tool
self.staticdirector = get_staticdirector(app_config)
# set up caching
self.cache = setup_beaker_cache()
# Setup celery, if appropriate
if setup_celery and not app_config.get('celery_setup_elsewhere'):
if os.environ.get('CELERY_ALWAYS_EAGER', 'false').lower() == 'true':
setup_celery_from_config(
app_config, global_config,
force_celery_always_eager=True)
else:
setup_celery_from_config(app_config, global_config)
#######################################################
# Insert appropriate things into mediagoblin.mg_globals
#
# certain properties need to be accessed globally eg from
# validators, etc, which might not access to the request
# object.
#######################################################
setup_globals(app=self)
# Workbench *currently* only used by celery, so this only
# matters in always eager mode :)
setup_workbench()
# instantiate application meddleware
self.meddleware = [common.import_component(m)(self)
for m in meddleware.ENABLED_MEDDLEWARE]
def call_backend(self, environ, start_response):
request = Request(environ)
## Routing / controller loading stuff
path_info = request.path_info
route_match = self.routing.match(path_info)
# By using fcgi, mediagoblin can run under a base path
# like /mediagoblin/. request.path_info contains the
# path inside mediagoblin. If the something needs the
# full path of the current page, that should include
# the basepath.
# Note: urlgen and routes are fine!
request.full_path = environ["SCRIPT_NAME"] + request.path_info
# python-routes uses SCRIPT_NAME. So let's use that too.
# The other option would be:
# request.full_path = environ["SCRIPT_URL"]
# Fix up environ for urlgen
# See bug: https://bitbucket.org/bbangert/routes/issue/55/cache_hostinfo-breaks-on-https-off
if environ.get('HTTPS', '').lower() == 'off':
environ.pop('HTTPS')
## Attach utilities to the request object
request.matchdict = route_match
request.urlgen = routes.URLGenerator(self.routing, environ)
# Do we really want to load this via middleware? Maybe?
request.session = request.environ['beaker.session']
# Attach self as request.app
# Also attach a few utilities from request.app for convenience?
request.app = self
request.locale = translate.get_locale_from_request(request)
request.template_env = template.get_jinja_env(
self.template_loader, request.locale)
request.db = self.db
request.staticdirect = self.staticdirector
mg_request.setup_user_in_request(request)
# No matching page?
if route_match is None:
# Try to do see if we have a match with a trailing slash
# added and if so, redirect
if not path_info.endswith('/') \
and request.method == 'GET' \
and self.routing.match(path_info + '/'):
new_path_info = path_info + '/'
if request.GET:
new_path_info = '%s?%s' % (
new_path_info, urllib.urlencode(request.GET))
redirect = exc.HTTPFound(location=new_path_info)
return request.get_response(redirect)(environ, start_response)
# Okay, no matches. 404 time!
request.matchdict = {} # in case our template expects it
return render_404(request)(environ, start_response)
# import the controller, or if it's already a callable, call that
route_controller = route_match['controller']
if isinstance(route_controller, unicode) \
or isinstance(route_controller, str):
controller = common.import_component(route_match['controller'])
else:
controller = route_match['controller']
# pass the request through our meddleware classes
for m in self.meddleware:
response = m.process_request(request, controller)
if response is not None:
return response(environ, start_response)
request.start_response = start_response
# get the response from the controller
response = controller(request)
# pass the response through the meddleware
for m in self.meddleware[::-1]:
m.process_response(request, response)
return response(environ, start_response)
def __call__(self, environ, start_response):
## If more errors happen that look like unclean sessions:
# self.db.check_session_clean()
try:
return self.call_backend(environ, start_response)
finally:
# Reset the sql session, so that the next request
# gets a fresh session
self.db.reset_after_request()
def paste_app_factory(global_config, **app_config):
configs = app_config['config'].split()
mediagoblin_config = None
for config in configs:
if os.path.exists(config) and os.access(config, os.R_OK):
mediagoblin_config = config
break
if not mediagoblin_config:
raise IOError("Usable mediagoblin config not found.")
mgoblin_app = MediaGoblinApp(mediagoblin_config)
return mgoblin_app