import cgi
import inspect
import mimetypes
import os
# See http://bugs.python.org/issue5853 which is a recursion bug
# that seems to effect Python 2.6, Python 2.6.1, and 2.6.2 (a fix
# has been applied on the Python 2 trunk). This workaround should
# really be in Paste if anywhere, but it's easiest to just do it
# here and get it over with to avoid needing to deal with any
# fallout.
if hasattr(mimetypes, 'init'):
mimetypes.init()
from webob import Response
from webob.exc import HTTPFound
from paste.urlparser import StaticURLParser
from zope.component import getSiteManager
from zope.component import providedBy
from zope.component import queryUtility
from zope.deprecation import deprecated
from zope.interface import implements
from repoze.bfg.interfaces import IAuthenticationPolicy
from repoze.bfg.interfaces import IAuthorizationPolicy
from repoze.bfg.interfaces import ILogger
from repoze.bfg.interfaces import IMultiView
from repoze.bfg.interfaces import IRendererFactory
from repoze.bfg.interfaces import IResponseFactory
from repoze.bfg.interfaces import IRoutesMapper
from repoze.bfg.interfaces import IView
from repoze.bfg.exceptions import NotFound
from repoze.bfg.exceptions import Forbidden
from repoze.bfg.path import caller_package
from repoze.bfg.renderers import renderer_from_name
from repoze.bfg.resource import resource_spec
from repoze.bfg.settings import get_settings
from repoze.bfg.static import PackageURLParser
# b/c imports
from repoze.bfg.security import view_execution_permitted
try:
all = all
except NameError: # pragma: no cover
def all(iterable):
for element in iterable:
if not element:
return False
return True
deprecated('view_execution_permitted',
"('from repoze.bfg.view import view_execution_permitted' was "
"deprecated as of repoze.bfg 1.0; instead use 'from "
"repoze.bfg.security import view_execution_permitted')",
)
deprecated('NotFound',
"('from repoze.bfg.view import NotFound' was "
"deprecated as of repoze.bfg 1.1; instead use 'from "
"repoze.bfg.exceptions import NotFound')",
)
_marker = object()
def render_view_to_response(context, request, name='', secure=True):
""" Render the view named ``name`` against the specified
``context`` and ``request`` to an object implementing
``repoze.bfg.interfaces.IResponse`` or ``None`` if no such view
exists. This function will return ``None`` if a corresponding
view cannot be found. If ``secure`` is ``True``, and the view is
protected by a permission, the permission will be checked before
calling the view function. If the permission check disallows view
execution (based on the current security policy), a
``repoze.bfg.exceptions.Forbidden`` exception will be raised; its
``args`` attribute explains why the view access was disallowed.
If ``secure`` is ``False``, no permission checking is done."""
provides = map(providedBy, (context, request))
sm = getSiteManager()
view = sm.adapters.lookup(provides, IView, name=name)
if view is None:
return None
if not secure:
# the view will have a __call_permissive__ attribute if it's
# secured; otherwise it won't.
view = getattr(view, '__call_permissive__', view)
# if this view is secured, it will raise a Forbidden
# appropriately if the executing user does not have the proper
# permission
return view(context, request)
def render_view_to_iterable(context, request, name='', secure=True):
""" Render the view named ``name`` against the specified
``context`` and ``request``, and return an iterable representing
the view response's ``app_iter`` (see the interface named
``repoze.bfg.interfaces.IResponse``). This function will return
``None`` if a corresponding view cannot be found. Additionally,
this function will raise a ``ValueError`` if a view function is
found and called but the view does not return an object which
implements ``repoze.bfg.interfaces.IResponse``. You can usually
get the string representation of the return value of this function
by calling ``''.join(iterable)``, or just use ``render_view``
instead. If ``secure`` is ``True``, and the view is protected by
a permission, the permission will be checked before calling the
view function. If the permission check disallows view execution
(based on the current security policy), a
``repoze.bfg.exceptions.Forbidden`` exception will be raised; its
``args`` attribute explains why the view access was disallowed.
If ``secure`` is ``False``, no permission checking is done."""
response = render_view_to_response(context, request, name, secure)
if response is None:
return None
return response.app_iter
def render_view(context, request, name='', secure=True):
""" Render the view named ``name`` against the specified
``context`` and ``request``, and unwind the the view response's
``app_iter`` (see the interface named
``repoze.bfg.interfaces.IResponse``) into a single string. This
function will return ``None`` if a corresponding view cannot be
found. Additionally, this function will raise a ``ValueError`` if
a view function is found and called but the view does not return
an object which implements ``repoze.bfg.interfaces.IResponse``.
If ``secure`` is ``True``, and the view is protected by a
permission, the permission will be checked before calling the view
function. If the permission check disallows view execution (based
on the current security policy), a
``repoze.bfg.exceptions.Forbidden`` exception will be raised; its
``args`` attribute explains why the view access was disallowed.
If ``secure`` is ``False``, no permission checking is done."""
iterable = render_view_to_iterable(context, request, name, secure)
if iterable is None:
return None
return ''.join(iterable)
def is_response(ob):
""" Return True if ``ob`` implements the
``repoze.bfg.interfaces.IResponse`` interface, False if not. Note
that this isn't actually a true Zope interface check, it's a
duck-typing check, as response objects are not obligated to
actually implement a Zope interface."""
# response objects aren't obligated to implement a Zope interface,
# so we do it the hard way
if ( hasattr(ob, 'app_iter') and hasattr(ob, 'headerlist') and
hasattr(ob, 'status') ):
if ( hasattr(ob.app_iter, '__iter__') and
hasattr(ob.headerlist, '__iter__') and
isinstance(ob.status, basestring) ) :
return True
return False
class static(object):
""" An instance of this class is a callable which can act as a BFG
view; this view will serve static files from a directory on disk
based on the ``root_dir`` you provide to its constructor.
The directory may contain subdirectories (recursively); the static
view implementation will descend into these directories as
necessary based on the components of the URL in order to resolve a
path into a response.
You may pass an absolute or relative filesystem path to the
directory containing static files directory to the constructor as
the ``root_dir`` argument.
If the path is relative, and the ``package`` argument is ``None``,
it will be considered relative to the directory in which the
Python file which calls ``static`` resides. If the ``package``
name argument is provided, and a relative ``root_dir`` is
provided, the ``root_dir`` will be considered relative to the
Python package specified by ``package_name`` (a dotted path to a
Python package).
``cache_max_age`` influences the Expires and Max-Age response
headers returned by the view (default is 3600 seconds or five
minutes). ``level`` influences how relative directories are
resolved (the number of hops in the call stack), not used very
often.
.. note:: If the ``root_dir`` is relative to a package, the BFG
``resource`` ZCML directive can be used to override resources
within the named ``root_dir`` package-relative directory.
However, if the ``root_dir`` is absolute, the ``resource``
directive will not be able to override the resources it
contains.
"""
def __init__(self, root_dir, cache_max_age=3600, level=2,
package_name=None):
# package_name is for bw compat; it is preferred to pass in a
# package-relative path as root_dir
# (e.g. ``anotherpackage:foo/static``).
if os.path.isabs(root_dir):
self.app = StaticURLParser(root_dir, cache_max_age=cache_max_age)
return
caller_package_name = caller_package().__name__
spec = resource_spec(root_dir, package_name or caller_package_name)
package_name, root_dir = spec.split(':', 1)
self.app = PackageURLParser(package_name, root_dir,
cache_max_age=cache_max_age)
def __call__(self, context, request):
subpath = '/'.join(request.subpath)
request_copy = request.copy()
# Fix up PATH_INFO to get rid of everything but the "subpath"
# (the actual path to the file relative to the root dir).
request_copy.environ['PATH_INFO'] = '/' + subpath
# Zero out SCRIPT_NAME for good measure.
request_copy.environ['SCRIPT_NAME'] = ''
return request_copy.get_response(self.app)
class bfg_view(object):
""" Function or class decorator which allows Python code to make
view registrations instead of using ZCML for the same purpose.
E.g. in the module ``views.py``::
from models import IMyModel
from repoze.bfg.interfaces import IRequest
@bfg_view(name='my_view', request_type=IRequest, for_=IMyModel,
permission='read', route_name='site1'))
def my_view(context, request):
return render_template_to_response('templates/my.pt')
Equates to the ZCML::
The following arguments are supported: ``for_``, ``permission``,
``name``, ``request_type``, ``route_name``, ``request_method``,
``request_param``, and ``containment``.
If ``for_`` is not supplied, the interface
``zope.interface.Interface`` (matching any context) is used.
If ``permission`` is not supplied, no permission is registered for
this view (it's accessible by any caller).
If ``name`` is not supplied, the empty string is used (implying
the default view name).
If ``attr`` is not supplied, ``None`` is used (implying the
function itself if the view is a function, or the ``__call__``
callable attribute if the view is a class).
If ``renderer`` is not supplied, ``None`` is used (meaning that no
renderer is associated with this view).
If ``wrapper`` is not supplied, ``None`` is used (meaning that no
view wrapper is associated with this view).
If ``request_type`` is not supplied, the interface
``repoze.bfg.interfaces.IRequest`` is used, implying the standard
request interface type.
If ``route_name`` is not supplied, the view declaration is
considered to be made against a URL that doesn't match any defined
:term:`route`. The use of a ``route_name`` is an advanced
feature, useful only if you're using :term:`url dispatch`.
If ``request_method`` is not supplied, this view will match a
request with any HTTP ``REQUEST_METHOD``
(GET/POST/PUT/HEAD/DELETE). If this parameter *is* supplied, it
must be a string naming an HTTP ``REQUEST_METHOD``, indicating
that this view will only match when the current request has a
``REQUEST_METHOD`` that matches this value.
If ``request_param`` is not supplied, this view will be called
when a request with any (or no) request GET or POST parameters is
encountered. If the value is present, it must be a string. If
the value supplied to the parameter has no ``=`` sign in it, it
implies that the key must exist in the ``request.params``
dictionary for this view to'match' the current request. If the value
supplied to the parameter has a ``=`` sign in it, e.g.
``request_params="foo=123"``, then the key (``foo``) must both exist
in the ``request.params`` dictionary, and the value must match the
right hand side of the expression (``123``) for the view to "match" the
current request.
If ``containment`` is not supplied, this view will be called when
the context of the request has any location lineage. If
``containment`` *is* supplied, it must be a class or :term:`interface`,
denoting that the view 'matches' the current request only if any graph
lineage node possesses this class or interface.
Any individual or all parameters can be omitted. The simplest
bfg_view declaration then becomes::
@bfg_view()
def my_view(...):
...
Such a registration implies that the view name will be
``my_view``, registered for models with the
``zope.interface.Interface`` interface, using no permission,
registered against requests which implement the default IRequest
interface when no urldispatch route matches, with any
REQUEST_METHOD, any set of request.params values, in any lineage
containment.
The ``bfg_view`` decorator can also be used as a class decorator
in Python 2.6 and better (Python 2.5 and below do not support
class decorators)::
from webob import Response
from repoze.bfg.view import bfg_view
@bfg_view()
class MyView(object):
def __init__(self, context, request):
self.context = context
self.request = request
def __call__(self):
return Response('hello from %s!' % self.context)
In Python 2.5 and below, the bfg_view decorator can still be used
against a class, although not in decorator form::
from webob import Response
from repoze.bfg.view import bfg_view
class MyView(object):
def __init__(self, context, request):
self.context = context
self.request = request
def __call__(self):
return Response('hello from %s!' % self.context)
MyView = bfg_view()(MyView)
.. note:: When a view is a class, the calling semantics are
different than when it is a function or another
non-class callable. See :ref:`class_as_view` for more
information.
.. warning:: Using a class as a view is a new feature in 0.8.1+.
To make use of any bfg_view declaration, you *must* insert the
following boilerplate into your application registry's ZCML::
"""
def __init__(self, name='', request_type=None, for_=None, permission=None,
route_name=None, request_method=None, request_param=None,
containment=None, attr=None, renderer=None, wrapper=None):
self.name = name
self.request_type = request_type
self.for_ = for_
self.permission = permission
self.route_name = route_name
self.request_method = request_method
self.request_param = request_param
self.containment = containment
self.attr = attr
self.renderer = renderer
self.wrapper_viewname = wrapper
def __call__(self, wrapped):
wrapped.__bfg_view_settings__ = self.__dict__.copy()
return wrapped
def default_view(context, request, status):
try:
msg = cgi.escape(request.environ['repoze.bfg.message'])
except KeyError:
msg = ''
html = """
%s
%s
%s
""" % (status, status, msg)
headers = [('Content-Length', str(len(html))),
('Content-Type', 'text/html')]
response_factory = queryUtility(IResponseFactory, default=Response)
return response_factory(status = status,
headerlist = headers,
app_iter = [html])
def default_forbidden_view(context, request):
return default_view(context, request, '401 Unauthorized')
def default_notfound_view(context, request):
return default_view(context, request, '404 Not Found')
class MultiView(object):
implements(IMultiView)
def __init__(self, name):
self.name = name
self.views = []
def add(self, view, score):
self.views.append((score, view))
self.views.sort()
def match(self, context, request):
for score, view in self.views:
if not hasattr(view, '__predicated__'):
return view
if view.__predicated__(context, request):
return view
raise NotFound(self.name)
def __permitted__(self, context, request):
view = self.match(context, request)
if hasattr(view, '__permitted__'):
return view.__permitted__(context, request)
return True
def __call_permissive__(self, context, request):
view = self.match(context, request)
view = getattr(view, '__call_permissive__', view)
return view(context, request)
def __call__(self, context, request):
for score, view in self.views:
try:
return view(context, request)
except NotFound:
continue
raise NotFound(self.name)
def rendered_response(renderer, response, view, context,request, renderer_name):
if ( hasattr(response, 'app_iter') and hasattr(response, 'headerlist') and
hasattr(response, 'status') ):
return response
result = renderer(response, {'view':view, 'renderer_name':renderer_name,
'context':context, 'request':request})
response_factory = queryUtility(IResponseFactory, default=Response)
response = response_factory(result)
attrs = request.environ.get('webob.adhoc_attrs', {})
content_type = attrs.get('response_content_type', None)
if content_type is not None:
response.content_type = content_type
headerlist = attrs.get('response_headerlist', None)
if headerlist is not None:
for k, v in headerlist:
response.headers.add(k, v)
status = attrs.get('response_status', None)
if status is not None:
response.status = status
charset = attrs.get('response_charset', None)
if charset is not None:
response.charset = charset
cache_for = attrs.get('response_cache_for', None)
if cache_for is not None:
response.cache_expires = cache_for
return response
def map_view(view, attr=None, renderer_name=None):
wrapped_view = view
renderer = None
if renderer_name is None:
factory = queryUtility(IRendererFactory) # global default renderer
if factory is not None:
renderer_name = ''
renderer = factory(renderer_name)
else:
renderer = renderer_from_name(renderer_name)
if inspect.isclass(view):
# If the object we've located is a class, turn it into a
# function that operates like a Zope view (when it's invoked,
# construct an instance using 'context' and 'request' as
# position arguments, then immediately invoke the __call__
# method of the instance with no arguments; __call__ should
# return an IResponse).
if requestonly(view, attr):
# its __init__ accepts only a single request argument,
# instead of both context and request
def _bfg_class_requestonly_view(context, request):
inst = view(request)
if attr is None:
response = inst()
else:
response = getattr(inst, attr)()
if renderer is not None:
response = rendered_response(renderer,
response, inst,
context, request,
renderer_name)
return response
wrapped_view = _bfg_class_requestonly_view
else:
# its __init__ accepts both context and request
def _bfg_class_view(context, request):
inst = view(context, request)
if attr is None:
response = inst()
else:
response = getattr(inst, attr)()
if renderer is not None:
response = rendered_response(renderer,
response, inst,
context, request,
renderer_name)
return response
wrapped_view = _bfg_class_view
elif requestonly(view, attr):
# its __call__ accepts only a single request argument,
# instead of both context and request
def _bfg_requestonly_view(context, request):
if attr is None:
response = view(request)
else:
response = getattr(view, attr)(request)
if renderer is not None:
response = rendered_response(renderer,
response, view,
context, request,
renderer_name)
return response
wrapped_view = _bfg_requestonly_view
elif attr:
def _bfg_attr_view(context, request):
response = getattr(view, attr)(context, request)
if renderer is not None:
response = rendered_response(renderer,
response, view,
context, request,
renderer_name)
return response
wrapped_view = _bfg_attr_view
elif renderer is not None:
def _rendered_view(context, request):
response = view(context, request)
response = rendered_response(renderer,
response, view,
context, request,
renderer_name)
return response
wrapped_view = _rendered_view
decorate_view(wrapped_view, view)
return wrapped_view
def requestonly(class_or_callable, attr=None):
""" Return true of the class or callable accepts only a request argument,
as opposed to something that accepts context, request """
if attr is None:
attr = '__call__'
if inspect.isfunction(class_or_callable):
fn = class_or_callable
elif inspect.isclass(class_or_callable):
try:
fn = class_or_callable.__init__
except AttributeError:
return False
else:
try:
fn = getattr(class_or_callable, attr)
except AttributeError:
return False
try:
argspec = inspect.getargspec(fn)
except TypeError:
return False
args = argspec[0]
defaults = argspec[3]
if hasattr(fn, 'im_func'):
# it's an instance method
if not args:
return False
args = args[1:]
if not args:
return False
if len(args) == 1:
return True
elif args[0] == 'request':
if len(args) - len(defaults) == 1:
return True
return False
def decorate_view(wrapped_view, original_view):
if wrapped_view is not original_view:
wrapped_view.__module__ = original_view.__module__
wrapped_view.__doc__ = original_view.__doc__
try:
wrapped_view.__name__ = original_view.__name__
except AttributeError:
wrapped_view.__name__ = repr(original_view)
try:
wrapped_view.__permitted__ = original_view.__permitted__
except AttributeError:
pass
try:
wrapped_view.__call_permissive__ = original_view.__call_permissive__
except AttributeError:
pass
try:
wrapped_view.__predicated__ = original_view.__predicated__
except AttributeError:
pass
return True
return False
def derive_view(original_view, permission=None, predicates=(), attr=None,
renderer_name=None, wrapper_viewname=None, viewname=None):
mapped_view = map_view(original_view, attr, renderer_name)
owrapped_view = owrap_view(mapped_view, viewname, wrapper_viewname)
secured_view = secure_view(owrapped_view, permission)
debug_view = authdebug_view(secured_view, permission)
derived_view = predicate_wrap(debug_view, predicates)
return derived_view
def owrap_view(view, viewname, wrapper_viewname):
if not wrapper_viewname:
return view
def _owrapped_view(context, request):
response = view(context, request)
request.wrapped_response = response
request.wrapped_body = response.body
request.wrapped_view = view
wrapped_response = render_view_to_response(context, request,
wrapper_viewname)
if wrapped_response is None:
raise ValueError(
'No wrapper view named %r found when executing view named %r' %
(wrapper_viewname, viewname))
return wrapped_response
decorate_view(_owrapped_view, view)
return _owrapped_view
def predicate_wrap(view, predicates):
if not predicates:
return view
def _wrapped(context, request):
if all((predicate(context, request) for predicate in predicates)):
return view(context, request)
raise NotFound('predicate mismatch for view %s' % view)
def checker(context, request):
return all((predicate(context, request) for predicate in predicates))
_wrapped.__predicated__ = checker
decorate_view(_wrapped, view)
return _wrapped
def secure_view(view, permission):
wrapped_view = view
authn_policy = queryUtility(IAuthenticationPolicy)
authz_policy = queryUtility(IAuthorizationPolicy)
if authn_policy and authz_policy and (permission is not None):
def _secured_view(context, request):
principals = authn_policy.effective_principals(request)
if authz_policy.permits(context, principals, permission):
return view(context, request)
msg = getattr(request, 'authdebug_message',
'Unauthorized: %s failed permission check' % view)
raise Forbidden(msg)
_secured_view.__call_permissive__ = view
def _permitted(context, request):
principals = authn_policy.effective_principals(request)
return authz_policy.permits(context, principals, permission)
_secured_view.__permitted__ = _permitted
wrapped_view = _secured_view
decorate_view(wrapped_view, view)
return wrapped_view
def authdebug_view(view, permission):
wrapped_view = view
authn_policy = queryUtility(IAuthenticationPolicy)
authz_policy = queryUtility(IAuthorizationPolicy)
settings = get_settings()
debug_authorization = False
if settings is not None:
debug_authorization = settings.get('debug_authorization', False)
if debug_authorization:
def _authdebug_view(context, request):
view_name = getattr(request, 'view_name', None)
if authn_policy and authz_policy:
if permission is None:
msg = 'Allowed (no permission registered)'
else:
principals = authn_policy.effective_principals(request)
msg = str(authz_policy.permits(context, principals,
permission))
else:
msg = 'Allowed (no authorization policy in use)'
view_name = getattr(request, 'view_name', None)
url = getattr(request, 'url', None)
msg = ('debug_authorization of url %s (view name %r against '
'context %r): %s' % (url, view_name, context, msg))
logger = queryUtility(ILogger, 'repoze.bfg.debug')
logger and logger.debug(msg)
if request is not None:
request.authdebug_message = msg
return view(context, request)
wrapped_view = _authdebug_view
decorate_view(wrapped_view, view)
return wrapped_view
def append_slash_notfound_view(context, request):
"""For behavior like Django's ``APPEND_SLASH=True``, use this view
as the Not Found view in your application.
When this view is the Not Found view (indicating that no view was
found), and any routes have been defined in the configuration of
your application, if the value of ``PATH_INFO`` does not already
end in a slash, and if the value of ``PATH_INFO`` *plus* a slash
matches any route's path, do an HTTP redirect to the
slash-appended PATH_INFO. Note that this will *lose* ``POST``
data information (turning it into a GET), so you shouldn't rely on
this to redirect POST requests.
Add the following to your application's ``configure.zcml`` to use
this view as the Not Found view::
See also :ref:`changing_the_notfound_view`.
.. note:: This function is new as of :mod:`repoze.bfg` version 1.1.
"""
path = request.environ.get('PATH_INFO', '/')
mapper = queryUtility(IRoutesMapper)
if mapper is not None and not path.endswith('/'):
slashpath = path + '/'
for route in mapper.get_routes():
if route.match(slashpath) is not None:
return HTTPFound(location=slashpath)
return default_view(context, request, '404 Not Found')