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Viewing changes to ivle/dispatch/__init__.py

  • Committer: William Grant
  • Date: 2010-02-24 07:22:43 UTC
  • Revision ID: grantw@unimelb.edu.au-20100224072243-xq5w2we8iuoteen1
Reword and reformat the tour a bit.

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ivle/dispatch/__init__.py
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import os
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import os.path
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import urllib
 
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import urlparse
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import cgi
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import traceback
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import logging
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import time
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import mod_python
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import routes
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from ivle import util
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import ivle.config
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import ivle.webapp.security
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from ivle.webapp.base.plugins import ViewPlugin, PublicViewPlugin
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from ivle.webapp.base.xhtml import XHTMLView, XHTMLErrorView
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from ivle.webapp.errors import HTTPError, Unauthorized, NotFound
 
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from ivle.webapp.errors import BadRequest, HTTPError, NotFound, Unauthorized
 
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from ivle.webapp.publisher import Publisher, PublishingError
 
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from ivle.webapp import ApplicationRoot
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config = ivle.config.Config()
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def generate_router(view_plugins, attr):
 
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class ObjectPermissionCheckingPublisher(Publisher):
 
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    """A specialised publisher that checks object permissions.
 
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    This publisher verifies that the user holds any permission at all
 
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    on the model objects through which the resolution path passes. If
 
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    no permission is held, resolution is aborted with an Unauthorized
 
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    exception.
 
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    IMPORTANT: This does NOT check view permissions. It only checks
 
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    the objects in between the root and the view, exclusive!
 
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    """
 
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    def traversed_to_object(self, obj):
 
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        """Check that the user has any permission at all over the object."""
 
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        if (hasattr(obj, 'get_permissions') and
 
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            len(obj.get_permissions(self.root.user, config)) == 0):
 
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            # Indicate the forbidden object if this is an admin.
 
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            if self.root.user and self.root.user.admin:
 
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                raise Unauthorized('Unauthorized: %s' % obj)
 
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            else:
 
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                raise Unauthorized()
 
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def generate_publisher(view_plugins, root, publicmode=False):
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    """
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    Build a Mapper object for doing URL matching using 'routes', based on the
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    given plugin registry.
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    """
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    m = routes.Mapper(explicit=True)
 
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    r = ObjectPermissionCheckingPublisher(root=root)
 
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    r.add_set_switch('api', 'api')
 
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    if publicmode:
 
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        view_attr = 'public_views'
 
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        forward_route_attr = 'public_forward_routes'
 
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        reverse_route_attr = 'public_reverse_routes'
 
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    else:
 
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        view_attr = 'views'
 
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        forward_route_attr = 'forward_routes'
 
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        reverse_route_attr = 'reverse_routes'
 
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    for plugin in view_plugins:
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        # Establish a URL pattern for each element of plugin.urls
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        assert hasattr(plugin, 'urls'), "%r does not have any urls" % plugin 
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        for url in getattr(plugin, attr):
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            routex = url[0]
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            view_class = url[1]
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            kwargs_dict = url[2] if len(url) >= 3 else {}
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            m.connect(routex, view=view_class, **kwargs_dict)
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    return m
 
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        if hasattr(plugin, forward_route_attr):
 
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            for fr in getattr(plugin, forward_route_attr):
 
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                # An annotated function can also be passed in directly.
 
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                if hasattr(fr, '_forward_route_meta'):
 
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                    r.add_forward_func(fr)
 
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                else:
 
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                    r.add_forward(*fr)
 
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        if hasattr(plugin, reverse_route_attr):
 
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            for rr in getattr(plugin, reverse_route_attr):
 
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                # An annotated function can also be passed in directly.
 
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                if hasattr(rr, '_reverse_route_src'):
 
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                    r.add_reverse_func(rr)
 
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                else:
 
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                    r.add_reverse(*rr)
 
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        if hasattr(plugin, view_attr):
 
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            for v in getattr(plugin, view_attr):
 
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                r.add_view(*v)
 
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    return r
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def handler(apachereq):
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    """Handles an HTTP request.
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        if user and user.valid:
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            req.user = user
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    if req.publicmode:
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        req.mapper = generate_router(config.plugin_index[PublicViewPlugin],
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                                    'public_urls')
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    else:
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        req.mapper = generate_router(config.plugin_index[ViewPlugin], 'urls')
 
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    req.publisher = generate_publisher(
 
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        config.plugin_index[ViewPlugin],
 
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        ApplicationRoot(req.config, req.store, req.user),
 
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        publicmode=req.publicmode)
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    matchdict = req.mapper.match(req.uri)
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    if matchdict is not None:
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        viewcls = matchdict['view']
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        # Get the remaining arguments, less 'view', 'action' and 'controller'
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        # (The latter two seem to be built-in, and we don't want them).
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        kwargs = matchdict.copy()
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        del kwargs['view']
 
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    try:
 
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        obj, viewcls, subpath = req.publisher.resolve(req.uri.decode('utf-8'))
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        try:
 
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            # We 404 if we have a subpath but the view forbids it.
 
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            if not viewcls.subpath_allowed and subpath:
 
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                raise NotFound()
 
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            # Instantiate the view, which should be a BaseView class
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            view = viewcls(req, **kwargs)
 
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            view = viewcls(req, obj, subpath)
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            # Check that the request (mainly the user) is permitted to access
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            # the view.
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            if not view.authorize(req):
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                raise Unauthorized()
 
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                # Indicate the forbidden object if this is an admin.
 
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                if req.user and req.user.admin:
 
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                    raise Unauthorized('Unauthorized: %s' % view)
 
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                else:
 
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                    raise Unauthorized()
 
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            # Non-GET requests from other sites leave us vulnerable to
 
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            # CSRFs. Block them.
 
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            referer = req.headers_in.get('Referer')
 
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            if (referer is None or
 
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                urlparse.urlparse(req.headers_in.get('Referer')).netloc !=
 
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                    req.hostname):
 
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                if req.method != 'GET' and not view.offsite_posts_allowed:
 
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                    raise BadRequest(
 
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                        "Non-GET requests from external sites are forbidden "
 
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                        "for security reasons.")
 
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            # Render the output
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            view.render(req)
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        except HTTPError, e:
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                errviewcls = XHTMLView.get_error_view(e)
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            if errviewcls:
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                errview = errviewcls(req, e)
 
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                errview = errviewcls(req, e, obj)
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                errview.render(req)
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                return req.OK
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            elif e.message:
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        else:
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            req.store.commit()
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            return req.OK
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    else:
 
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    except Unauthorized, e:
 
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        # Resolution failed due to a permission check. Display a pretty
 
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        # error, or maybe a login page.
 
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        XHTMLView.get_error_view(e)(req, e, req.publisher.root).render(req)
 
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        return req.OK
 
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    except PublishingError, e:
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        req.status = 404
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        XHTMLErrorView(req, NotFound()).render(req)
 
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        if req.user and req.user.admin:
 
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            XHTMLErrorView(req, NotFound('Not found: ' +
 
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                                         str(e.args)), e[0]).render(req)
 
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        else:
 
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            XHTMLErrorView(req, NotFound(), e[0]).render(req)
 
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        return req.OK
 
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    finally:
 
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        req.store.close()
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def handle_unknown_exception(req, exc_type, exc_value, exc_traceback):
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    """