/
flask_app.py
425 lines (333 loc) · 13.5 KB
/
flask_app.py
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# encoding: utf-8
import os
import re
import inspect
import itertools
import pkgutil
from flask import Flask, Blueprint
from flask.ctx import _AppCtxGlobals
from flask.sessions import SessionInterface
from werkzeug.exceptions import default_exceptions, HTTPException
from werkzeug.routing import Rule
from flask_babel import Babel
from beaker.middleware import SessionMiddleware
from paste.deploy.converters import asbool
from fanstatic import Fanstatic
from repoze.who.config import WhoConfig
from repoze.who.middleware import PluggableAuthenticationMiddleware
import ckan.model as model
from ckan.lib import base
from ckan.lib import helpers
from ckan.lib import jinja_extensions
from ckan.common import config, g, request, ungettext
import ckan.lib.app_globals as app_globals
from ckan.plugins import PluginImplementations
from ckan.plugins.interfaces import IBlueprint, IMiddleware, ITranslation
from ckan.views import (identify_user,
set_cors_headers_for_response,
check_session_cookie,
set_controller_and_action
)
import logging
log = logging.getLogger(__name__)
class CKANBabel(Babel):
def __init__(self, *pargs, **kwargs):
super(CKANBabel, self).__init__(*pargs, **kwargs)
self._i18n_path_idx = 0
@property
def domain(self):
default = super(CKANBabel, self).domain
multiple = self.app.config.get('BABEL_MULTIPLE_DOMAINS')
if not multiple:
return default
domains = multiple.split(';')
try:
return domains[self._i18n_path_idx]
except IndexError:
return default
@property
def translation_directories(self):
self._i18n_path_idx = 0
for path in super(CKANBabel, self).translation_directories:
yield path
self._i18n_path_idx += 1
def make_flask_stack(conf, **app_conf):
""" This has to pass the flask app through all the same middleware that
Pylons used """
root = os.path.dirname(
os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
debug = asbool(conf.get('debug', conf.get('DEBUG', False)))
testing = asbool(app_conf.get('testing', app_conf.get('TESTING', False)))
app = flask_app = CKANFlask(__name__)
app.debug = debug
app.testing = testing
app.template_folder = os.path.join(root, 'templates')
app.app_ctx_globals_class = CKAN_AppCtxGlobals
app.url_rule_class = CKAN_Rule
app.jinja_options = jinja_extensions.get_jinja_env_options()
# Update Flask config with the CKAN values. We use the common config
# object as values might have been modified on `load_environment`
if config:
app.config.update(config)
else:
app.config.update(conf)
app.config.update(app_conf)
# Do all the Flask-specific stuff before adding other middlewares
# Secret key needed for flask-debug-toolbar and sessions
if not app.config.get('SECRET_KEY'):
app.config['SECRET_KEY'] = config.get('beaker.session.secret')
if not app.config.get('SECRET_KEY'):
raise RuntimeError(u'You must provide a value for the secret key'
' with the SECRET_KEY config option')
if debug:
from flask_debugtoolbar import DebugToolbarExtension
app.config['DEBUG_TB_INTERCEPT_REDIRECTS'] = False
DebugToolbarExtension(app)
# Use Beaker as the Flask session interface
class BeakerSessionInterface(SessionInterface):
def open_session(self, app, request):
if 'beaker.session' in request.environ:
return request.environ['beaker.session']
def save_session(self, app, session, response):
session.save()
namespace = 'beaker.session.'
session_opts = dict([(k.replace('beaker.', ''), v)
for k, v in config.iteritems()
if k.startswith(namespace)])
if (not session_opts.get('session.data_dir') and
session_opts.get('session.type', 'file') == 'file'):
cache_dir = app_conf.get('cache_dir') or app_conf.get('cache.dir')
session_opts['session.data_dir'] = '{data_dir}/sessions'.format(
data_dir=cache_dir)
app.wsgi_app = SessionMiddleware(app.wsgi_app, session_opts)
app.session_interface = BeakerSessionInterface()
# Add Jinja2 extensions and filters
app.jinja_env.filters['empty_and_escape'] = \
jinja_extensions.empty_and_escape
# Common handlers for all requests
app.before_request(ckan_before_request)
app.after_request(ckan_after_request)
# Template context processors
app.context_processor(helper_functions)
app.context_processor(c_object)
@app.context_processor
def ungettext_alias():
u'''
Provide `ungettext` as an alias of `ngettext` for backwards
compatibility
'''
return dict(ungettext=ungettext)
# Babel
pairs = [(os.path.join(root, u'i18n'), 'ckan')] + [
(p.i18n_directory(), p.i18n_domain())
for p in PluginImplementations(ITranslation)
]
i18n_dirs, i18n_domains = zip(*pairs)
app.config[u'BABEL_TRANSLATION_DIRECTORIES'] = ';'.join(i18n_dirs)
app.config[u'BABEL_DOMAIN'] = 'ckan'
app.config[u'BABEL_MULTIPLE_DOMAINS'] = ';'.join(i18n_domains)
babel = CKANBabel(app)
babel.localeselector(get_locale)
@app.route('/hello', methods=['GET'])
def hello_world():
return 'Hello World, this is served by Flask'
@app.route('/hello', methods=['POST'])
def hello_world_post():
return 'Hello World, this was posted to Flask'
# Auto-register all blueprints defined in the `views` folder
_register_core_blueprints(app)
_register_error_handler(app)
# Set up each IBlueprint extension as a Flask Blueprint
for plugin in PluginImplementations(IBlueprint):
if hasattr(plugin, 'get_blueprint'):
app.register_extension_blueprint(plugin.get_blueprint())
# Set flask routes in named_routes
for rule in app.url_map.iter_rules():
if '.' not in rule.endpoint:
continue
controller, action = rule.endpoint.split('.')
needed = list(rule.arguments - set(rule.defaults or {}))
route = {
rule.endpoint: {
'action': action,
'controller': controller,
'highlight_actions': action,
'needed': needed
}
}
config['routes.named_routes'].update(route)
# Start other middleware
for plugin in PluginImplementations(IMiddleware):
app = plugin.make_middleware(app, config)
# Fanstatic
if debug:
fanstatic_config = {
'versioning': True,
'recompute_hashes': True,
'minified': False,
'bottom': True,
'bundle': False,
}
else:
fanstatic_config = {
'versioning': True,
'recompute_hashes': False,
'minified': True,
'bottom': True,
'bundle': True,
}
root_path = config.get('ckan.root_path', None)
if root_path:
root_path = re.sub('/{{LANG}}', '', root_path)
fanstatic_config['base_url'] = root_path
app = Fanstatic(app, **fanstatic_config)
for plugin in PluginImplementations(IMiddleware):
try:
app = plugin.make_error_log_middleware(app, config)
except AttributeError:
log.critical('Middleware class {0} is missing the method'
'make_error_log_middleware.'
.format(plugin.__class__.__name__))
# Initialize repoze.who
who_parser = WhoConfig(conf['here'])
who_parser.parse(open(app_conf['who.config_file']))
app = PluggableAuthenticationMiddleware(
app,
who_parser.identifiers,
who_parser.authenticators,
who_parser.challengers,
who_parser.mdproviders,
who_parser.request_classifier,
who_parser.challenge_decider,
logging.getLogger('repoze.who'),
logging.WARN, # ignored
who_parser.remote_user_key
)
# Update the main CKAN config object with the Flask specific keys
# that were set here or autogenerated
flask_config_keys = set(flask_app.config.keys()) - set(config.keys())
for key in flask_config_keys:
config[key] = flask_app.config[key]
# Add a reference to the actual Flask app so it's easier to access
app._wsgi_app = flask_app
return app
def get_locale():
u'''
Return the value of the `CKAN_LANG` key of the WSGI environ,
set by the I18nMiddleware based on the URL.
If no value is defined, it defaults to `ckan.locale_default` or `en`.
'''
return request.environ.get(
u'CKAN_LANG',
config.get(u'ckan.locale_default', u'en'))
def ckan_before_request():
u'''Common handler executed before all Flask requests'''
# Update app_globals
app_globals.app_globals._check_uptodate()
# Identify the user from the repoze cookie or the API header
# Sets g.user and g.userobj
identify_user()
# Provide g.controller and g.action for backward compatibility
# with extensions
set_controller_and_action()
def ckan_after_request(response):
u'''Common handler executed after all Flask requests'''
# Dispose of the SQLALchemy session
model.Session.remove()
# Check session cookie
response = check_session_cookie(response)
# Set CORS headers if necessary
response = set_cors_headers_for_response(response)
return response
def helper_functions():
u'''Make helper functions (`h`) available to Flask templates'''
helpers.load_plugin_helpers()
return dict(h=helpers.helper_functions)
def c_object():
u'''
Expose `c` as an alias of `g` in templates for backwards compatibility
'''
return dict(c=g)
class CKAN_Rule(Rule):
u'''Custom Flask url_rule_class.
We use it to be able to flag routes defined in extensions as such
'''
def __init__(self, *args, **kwargs):
self.ckan_core = True
super(CKAN_Rule, self).__init__(*args, **kwargs)
class CKAN_AppCtxGlobals(_AppCtxGlobals):
'''Custom Flask AppCtxGlobal class (flask.g).'''
def __getattr__(self, name):
'''
If flask.g doesn't have attribute `name`, fall back to CKAN's
app_globals object.
If the key is also not found in there, an AttributeError will be raised
'''
return getattr(app_globals.app_globals, name)
class CKANFlask(Flask):
'''Extend the Flask class with a special method called on incoming
requests by AskAppDispatcherMiddleware.
'''
app_name = 'flask_app'
def can_handle_request(self, environ):
'''
Decides whether it can handle a request with the Flask app by
matching the request environ against the route mapper
Returns (True, 'flask_app', origin) if this is the case.
`origin` can be either 'core' or 'extension' depending on where
the route was defined.
'''
urls = self.url_map.bind_to_environ(environ)
try:
rule, args = urls.match(return_rule=True)
origin = 'core'
if hasattr(rule, 'ckan_core') and not rule.ckan_core:
origin = 'extension'
log.debug('Flask route match, endpoint: {0}, args: {1}, '
'origin: {2}'.format(rule.endpoint, args, origin))
return (True, self.app_name, origin)
except HTTPException:
return (False, self.app_name)
def register_extension_blueprint(self, blueprint, **kwargs):
'''
This method should be used to register blueprints that come from
extensions, so there's an opportunity to add extension-specific
options.
Sets the rule property `ckan_core` to False, to indicate that the rule
applies to an extension route.
'''
self.register_blueprint(blueprint, **kwargs)
# Get the new blueprint rules
bp_rules = itertools.chain.from_iterable(
v for k, v in self.url_map._rules_by_endpoint.iteritems()
if k.startswith(u'{0}.'.format(blueprint.name))
)
# This compare key will ensure the rule will be near the top.
top_compare_key = False, -100, [(-2, 0)]
for r in bp_rules:
r.ckan_core = False
r.match_compare_key = lambda: top_compare_key
def _register_core_blueprints(app):
u'''Register all blueprints defined in the `views` folder
'''
def is_blueprint(mm):
return isinstance(mm, Blueprint)
path = os.path.join(os.path.dirname(__file__), '..', '..', 'views')
for loader, name, _ in pkgutil.iter_modules([path], 'ckan.views.'):
module = loader.find_module(name).load_module(name)
for blueprint in inspect.getmembers(module, is_blueprint):
app.register_blueprint(blueprint[1])
log.debug(u'Registered core blueprint: {0!r}'.format(blueprint[0]))
def _register_error_handler(app):
u'''Register error handler'''
def error_handler(e):
if isinstance(e, HTTPException):
extra_vars = {u'code': [e.code], u'content': e.description}
return base.render(
u'error_document_template.html', extra_vars), e.code
extra_vars = {u'code': [500], u'content': u'Internal server error'}
return base.render(u'error_document_template.html', extra_vars), 500
for code in default_exceptions:
app.register_error_handler(code, error_handler)
if not app.debug and not app.testing:
app.register_error_handler(Exception, error_handler)