Move view-related helper functions from zcml.py to view.py.

1 files changed, 112 insertions, 2 deletions

diff --git a/repoze/bfg/view.py b/repoze/bfg/view.py
index e5a6e5398..12c8b6f46 100644
--- a/repoze/bfg/view.py
+++ b/repoze/bfg/view.py
@@ -25,6 +25,9 @@ from zope.interface import implements
 
 from zope.deprecation import deprecated
 
+from repoze.bfg.interfaces import IAuthenticationPolicy
+from repoze.bfg.interfaces import IAuthorizationPolicy
+from repoze.bfg.interfaces import ILogger
 from repoze.bfg.interfaces import IResponseFactory
 from repoze.bfg.interfaces import IRendererFactory
 from repoze.bfg.interfaces import IView
@@ -32,11 +35,20 @@ from repoze.bfg.interfaces import IMultiView
 from repoze.bfg.interfaces import ITemplateRenderer
 
 from repoze.bfg.path import caller_package
-
+from repoze.bfg.security import Unauthorized
+from repoze.bfg.settings import get_settings
 from repoze.bfg.static import PackageURLParser
-
 from repoze.bfg.renderers import renderer_from_name
 
+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 "
@@ -608,3 +620,101 @@ def decorate_view(wrapped_view, original_view):
             pass
         return True
     return False
+
+def derive_view(original_view, permission=None, predicates=(), attr=None,
+                renderer=None, wrapper_viewname=None, viewname=None):
+    mapped_view = map_view(original_view, attr, renderer)
+    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 Unauthorized(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 = getattr(settings, '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
+