> Read the latest version of this page
Edit me on GitHub

Source code for pyramid.traversal

import urllib

from zope.interface import implements
from zope.interface.interfaces import IInterface
from zope.deprecation import deprecated

from repoze.lru import lru_cache

from pyramid.interfaces import IContextURL
from pyramid.interfaces import IRequestFactory
from pyramid.interfaces import ITraverser
from pyramid.interfaces import VH_ROOT_KEY

from pyramid.encode import url_quote
from pyramid.exceptions import URLDecodeError
from pyramid.location import lineage
from pyramid.threadlocal import get_current_registry

[docs]def find_root(resource): """ Find the root node in the resource tree to which ``resource`` belongs. Note that ``resource`` should be :term:`location`-aware. Note that the root resource is available in the request object by accessing the ``request.root`` attribute. """ for location in lineage(resource): if location.__parent__ is None: resource = location break return resource
[docs]def find_resource(resource, path): """ Given a resource object and a string or tuple representing a path (such as the return value of :func:`pyramid.traversal.resource_path` or :func:`pyramid.traversal.resource_path_tuple`), return a resource in this application's resource tree at the specified path. The resource passed in *must* be :term:`location`-aware. If the path cannot be resolved (if the respective node in the resource tree does not exist), a :exc:`KeyError` will be raised. This function is the logical inverse of :func:`pyramid.traversal.resource_path` and :func:`pyramid.traversal.resource_path_tuple`; it can resolve any path string or tuple generated by either of those functions. Rules for passing a *string* as the ``path`` argument: if the first character in the path string is the with the ``/`` character, the path will considered absolute and the resource tree traversal will start at the root resource. If the first character of the path string is *not* the ``/`` character, the path is considered relative and resource tree traversal will begin at the resource object supplied to the function as the ``resource`` argument. If an empty string is passed as ``path``, the ``resource`` passed in will be returned. Resource path strings must be escaped in the following manner: each Unicode path segment must be encoded as UTF-8 and as each path segment must escaped via Python's :mod:`urllib.quote`. For example, ``/path/to%20the/La%20Pe%C3%B1a`` (absolute) or ``to%20the/La%20Pe%C3%B1a`` (relative). The :func:`pyramid.traversal.resource_path` function generates strings which follow these rules (albeit only absolute ones). Rules for passing a *tuple* as the ``path`` argument: if the first element in the path tuple is the empty string (for example ``('', 'a', 'b', 'c')``, the path is considered absolute and the resource tree traversal will start at the resource tree root object. If the first element in the path tuple is not the empty string (for example ``('a', 'b', 'c')``), the path is considered relative and resource tree traversal will begin at the resource object supplied to the function as the ``resource`` argument. If an empty sequence is passed as ``path``, the ``resource`` passed in itself will be returned. No URL-quoting or UTF-8-encoding of individual path segments within the tuple is required (each segment may be any string or unicode object representing a resource name). Resource path tuples generated by :func:`pyramid.traversal.resource_path_tuple` can always be resolved by ``find_resource``. .. note:: For backwards compatibility purposes, this function can also be imported as :func:`pyramid.traversal.find_model`, although doing so will emit a deprecation warning. """ D = traverse(resource, path) view_name = D['view_name'] context = D['context'] if view_name: raise KeyError('%r has no subelement %s' % (context, view_name)) return context
find_model = find_resource # b/w compat deprecated( 'find_model', 'pyramid.traversal.find_model is deprecated as of Pyramid 1.0. Use' '``pyramid.traversal.find_resource`` instead (API-compat, simple ' 'rename).')
[docs]def find_interface(resource, class_or_interface): """ Return the first resource found in the :term:`lineage` of ``resource`` which, a) if ``class_or_interface`` is a Python class object, is an instance of the class or any subclass of that class or b) if ``class_or_interface`` is a :term:`interface`, provides the specified interface. Return ``None`` if no resource providing ``interface_or_class`` can be found in the lineage. The ``resource`` passed in *must* be :term:`location`-aware. """ if IInterface.providedBy(class_or_interface): test = class_or_interface.providedBy else: test = lambda arg: isinstance(arg, class_or_interface) for location in lineage(resource): if test(location): return location
[docs]def resource_path(resource, *elements): """ Return a string object representing the absolute physical path of the resource object based on its position in the resource tree, e.g ``/foo/bar``. Any positional arguments passed in as ``elements`` will be appended as path segments to the end of the resource path. For instance, if the resource's path is ``/foo/bar`` and ``elements`` equals ``('a', 'b')``, the returned string will be ``/foo/bar/a/b``. The first character in the string will always be the ``/`` character (a leading ``/`` character in a path string represents that the path is absolute). Resource path strings returned will be escaped in the following manner: each unicode path segment will be encoded as UTF-8 and each path segment will be escaped via Python's :mod:`urllib.quote`. For example, ``/path/to%20the/La%20Pe%C3%B1a``. This function is a logical inverse of :mod:`pyramid.traversal.find_resource`: it can be used to generate path references that can later be resolved via that function. The ``resource`` passed in *must* be :term:`location`-aware. .. note:: Each segment in the path string returned will use the ``__name__`` attribute of the resource it represents within the resource tree. Each of these segments *should* be a unicode or string object (as per the contract of :term:`location`-awareness). However, no conversion or safety checking of resource names is performed. For instance, if one of the resources in your tree has a ``__name__`` which (by error) is a dictionary, the :func:`pyramid.traversal.resource_path` function will attempt to append it to a string and it will cause a :exc:`pyramid.exceptions.URLDecodeError`. .. note:: The :term:`root` resource *must* have a ``__name__`` attribute with a value of either ``None`` or the empty string for paths to be generated properly. If the root resource has a non-null ``__name__`` attribute, its name will be prepended to the generated path rather than a single leading '/' character. .. note:: For backwards compatibility purposes, this function can also be imported as ``model_path``, although doing so will cause a deprecation warning to be emitted. """ # joining strings is a bit expensive so we delegate to a function # which caches the joined result for us return _join_path_tuple(resource_path_tuple(resource, *elements))
model_path = resource_path # b/w compat deprecated( 'model_path', 'pyramid.traversal.model_path is deprecated as of Pyramid 1.0. Use' '``pyramid.traversal.resource_path`` instead (API-compat, simple rename).')
[docs]def traverse(resource, path): """Given a resource object as ``resource`` and a string or tuple representing a path as ``path`` (such as the return value of :func:`pyramid.traversal.resource_path` or :func:`pyramid.traversal.resource_path_tuple` or the value of ``request.environ['PATH_INFO']``), return a dictionary with the keys ``context``, ``root``, ``view_name``, ``subpath``, ``traversed``, ``virtual_root``, and ``virtual_root_path``. A definition of each value in the returned dictionary: - ``context``: The :term:`context` (a :term:`resource` object) found via traversal or url dispatch. If the ``path`` passed in is the empty string, the value of the ``resource`` argument passed to this function is returned. - ``root``: The resource object at which :term:`traversal` begins. If the ``resource`` passed in was found via url dispatch or if the ``path`` passed in was relative (non-absolute), the value of the ``resource`` argument passed to this function is returned. - ``view_name``: The :term:`view name` found during :term:`traversal` or :term:`url dispatch`; if the ``resource`` was found via traversal, this is usually a representation of the path segment which directly follows the path to the ``context`` in the ``path``. The ``view_name`` will be a Unicode object or the empty string. The ``view_name`` will be the empty string if there is no element which follows the ``context`` path. An example: if the path passed is ``/foo/bar``, and a resource object is found at ``/foo`` (but not at ``/foo/bar``), the 'view name' will be ``u'bar'``. If the ``resource`` was found via urldispatch, the view_name will be the name the route found was registered with. - ``subpath``: For a ``resource`` found via :term:`traversal`, this is a sequence of path segments found in the ``path`` that follow the ``view_name`` (if any). Each of these items is a Unicode object. If no path segments follow the ``view_name``, the subpath will be the empty sequence. An example: if the path passed is ``/foo/bar/baz/buz``, and a resource object is found at ``/foo`` (but not ``/foo/bar``), the 'view name' will be ``u'bar'`` and the :term:`subpath` will be ``[u'baz', u'buz']``. For a ``resource`` found via url dispatch, the subpath will be a sequence of values discerned from ``*subpath`` in the route pattern matched or the empty sequence. - ``traversed``: The sequence of path elements traversed from the root to find the ``context`` object during :term:`traversal`. Each of these items is a Unicode object. If no path segments were traversed to find the ``context`` object (e.g. if the ``path`` provided is the empty string), the ``traversed`` value will be the empty sequence. If the ``resource`` is a resource found via :term:`url dispatch`, traversed will be None. - ``virtual_root``: A resource object representing the 'virtual' root of the resource tree being traversed during :term:`traversal`. See :ref:`vhosting_chapter` for a definition of the virtual root object. If no virtual hosting is in effect, and the ``path`` passed in was absolute, the ``virtual_root`` will be the *physical* root resource object (the object at which :term:`traversal` begins). If the ``resource`` passed in was found via :term:`URL dispatch` or if the ``path`` passed in was relative, the ``virtual_root`` will always equal the ``root`` object (the resource passed in). - ``virtual_root_path`` -- If :term:`traversal` was used to find the ``resource``, this will be the sequence of path elements traversed to find the ``virtual_root`` resource. Each of these items is a Unicode object. If no path segments were traversed to find the ``virtual_root`` resource (e.g. if virtual hosting is not in effect), the ``traversed`` value will be the empty list. If url dispatch was used to find the ``resource``, this will be ``None``. If the path cannot be resolved, a :exc:`KeyError` will be raised. Rules for passing a *string* as the ``path`` argument: if the first character in the path string is the with the ``/`` character, the path will considered absolute and the resource tree traversal will start at the root resource. If the first character of the path string is *not* the ``/`` character, the path is considered relative and resource tree traversal will begin at the resource object supplied to the function as the ``resource`` argument. If an empty string is passed as ``path``, the ``resource`` passed in will be returned. Resource path strings must be escaped in the following manner: each Unicode path segment must be encoded as UTF-8 and each path segment must escaped via Python's :mod:`urllib.quote`. For example, ``/path/to%20the/La%20Pe%C3%B1a`` (absolute) or ``to%20the/La%20Pe%C3%B1a`` (relative). The :func:`pyramid.traversal.resource_path` function generates strings which follow these rules (albeit only absolute ones). Rules for passing a *tuple* as the ``path`` argument: if the first element in the path tuple is the empty string (for example ``('', 'a', 'b', 'c')``, the path is considered absolute and the resource tree traversal will start at the resource tree root object. If the first element in the path tuple is not the empty string (for example ``('a', 'b', 'c')``), the path is considered relative and resource tree traversal will begin at the resource object supplied to the function as the ``resource`` argument. If an empty sequence is passed as ``path``, the ``resource`` passed in itself will be returned. No URL-quoting or UTF-8-encoding of individual path segments within the tuple is required (each segment may be any string or unicode object representing a resource name). Explanation of the conversion of ``path`` segment values to Unicode during traversal: Each segment is URL-unquoted, and decoded into Unicode. Each segment is assumed to be encoded using the UTF-8 encoding (or a subset, such as ASCII); a :exc:`pyramid.exceptions.URLDecodeError` is raised if a segment cannot be decoded. If a segment name is empty or if it is ``.``, it is ignored. If a segment name is ``..``, the previous segment is deleted, and the ``..`` is ignored. As a result of this process, the return values ``view_name``, each element in the ``subpath``, each element in ``traversed``, and each element in the ``virtual_root_path`` will be Unicode as opposed to a string, and will be URL-decoded. """ if hasattr(path, '__iter__'): # the traverser factory expects PATH_INFO to be a string, not # unicode and it expects path segments to be utf-8 and # urlencoded (it's the same traverser which accepts PATH_INFO # from user agents; user agents always send strings). if path: path = _join_path_tuple(tuple(path)) else: path = '' # The user is supposed to pass us a string object, never Unicode. In # practice, however, users indeed pass Unicode to this API. If they do # pass a Unicode object, its data *must* be entirely encodeable to ASCII, # so we encode it here as a convenience to the user and to prevent # second-order failures from cropping up (all failures will occur at this # step rather than later down the line as the result of calling # ``traversal_path``). if isinstance(path, unicode): path = path.encode('ascii') if path and path[0] == '/': resource = find_root(resource) reg = get_current_registry() request_factory = reg.queryUtility(IRequestFactory) if request_factory is None: from pyramid.request import Request # avoid circdep request_factory = Request request = request_factory.blank(path) request.registry = reg traverser = reg.queryAdapter(resource, ITraverser) if traverser is None: traverser = ResourceTreeTraverser(resource) return traverser(request)
[docs]def resource_path_tuple(resource, *elements): """ Return a tuple representing the absolute physical path of the ``resource`` object based on its position in a resource tree, e.g ``('', 'foo', 'bar')``. Any positional arguments passed in as ``elements`` will be appended as elements in the tuple representing the resource path. For instance, if the resource's path is ``('', 'foo', 'bar')`` and elements equals ``('a', 'b')``, the returned tuple will be ``('', 'foo', 'bar', 'a', b')``. The first element of this tuple will always be the empty string (a leading empty string element in a path tuple represents that the path is absolute). This function is a logical inverse of :func:`pyramid.traversal.find_resource`: it can be used to generate path references that can later be resolved that function. The ``resource`` passed in *must* be :term:`location`-aware. .. note:: Each segment in the path tuple returned will equal the ``__name__`` attribute of the resource it represents within the resource tree. Each of these segments *should* be a unicode or string object (as per the contract of :term:`location`-awareness). However, no conversion or safety checking of resource names is performed. For instance, if one of the resources in your tree has a ``__name__`` which (by error) is a dictionary, that dictionary will be placed in the path tuple; no warning or error will be given. .. note:: The :term:`root` resource *must* have a ``__name__`` attribute with a value of either ``None`` or the empty string for path tuples to be generated properly. If the root resource has a non-null ``__name__`` attribute, its name will be the first element in the generated path tuple rather than the empty string. .. note:: For backwards compatibility purposes, this function can also be imported as ``model_path_tuple``, although doing so will cause a deprecation warning to be emitted. """ return tuple(_resource_path_list(resource, *elements))
model_path_tuple = resource_path_tuple # b/w compat deprecated( 'model_path_tuple', 'pyramid.traversal.model_path_tuple is deprecated as of Pyramid 1.0. Use' '``pyramid.traversal.resource_path_tuple`` instead (API-compat, simple ' 'rename).') def _resource_path_list(resource, *elements): """ Implementation detail shared by resource_path and resource_path_tuple""" path = [loc.__name__ or '' for loc in lineage(resource)] path.reverse() path.extend(elements) return path _model_path_list = _resource_path_list # b/w compat, not an API
[docs]def virtual_root(resource, request): """ Provided any :term:`resource` and a :term:`request` object, return the resource object representing the :term:`virtual root` of the current :term:`request`. Using a virtual root in a :term:`traversal` -based :app:`Pyramid` application permits rooting, for example, the resource at the traversal path ``/cms`` at ``http://example.com/`` instead of rooting it at ``http://example.com/cms/``. If the ``resource`` passed in is a context obtained via :term:`traversal`, and if the ``HTTP_X_VHM_ROOT`` key is in the WSGI environment, the value of this key will be treated as a 'virtual root path': the :func:`pyramid.traversal.find_resource` API will be used to find the virtual root resource using this path; if the resource is found, it will be returned. If the ``HTTP_X_VHM_ROOT`` key is is not present in the WSGI environment, the physical :term:`root` of the resource tree will be returned instead. Virtual roots are not useful at all in applications that use :term:`URL dispatch`. Contexts obtained via URL dispatch don't really support being virtually rooted (each URL dispatch context is both its own physical and virtual root). However if this API is called with a ``resource`` argument which is a context obtained via URL dispatch, the resource passed in will be returned unconditionally.""" try: reg = request.registry except AttributeError: reg = get_current_registry() # b/c urlgenerator = reg.queryMultiAdapter((resource, request), IContextURL) if urlgenerator is None: urlgenerator = TraversalContextURL(resource, request) return urlgenerator.virtual_root()
@lru_cache(1000)
[docs]def traversal_path(path): """ Given a ``PATH_INFO`` string (slash-separated path segments), return a tuple representing that path which can be used to traverse a resource tree. The ``PATH_INFO`` is split on slashes, creating a list of segments. Each segment is URL-unquoted, and subsequently decoded into Unicode. Each segment is assumed to be encoded using the UTF-8 encoding (or a subset, such as ASCII); a :exc:`pyramid.exceptions.URLDecodeError` is raised if a segment cannot be decoded. If a segment name is empty or if it is ``.``, it is ignored. If a segment name is ``..``, the previous segment is deleted, and the ``..`` is ignored. If this function is passed a Unicode object instead of a string, that Unicode object *must* directly encodeable to ASCII. For example, u'/foo' will work but u'/<unprintable unicode>' (a Unicode object with characters that cannot be encoded to ascii) will not. Examples: ``/`` () ``/foo/bar/baz`` (u'foo', u'bar', u'baz') ``foo/bar/baz`` (u'foo', u'bar', u'baz') ``/foo/bar/baz/`` (u'foo', u'bar', u'baz') ``/foo//bar//baz/`` (u'foo', u'bar', u'baz') ``/foo/bar/baz/..`` (u'foo', u'bar') ``/my%20archives/hello`` (u'my archives', u'hello') ``/archives/La%20Pe%C3%B1a`` (u'archives', u'<unprintable unicode>') .. note:: This function does not generate the same type of tuples that :func:`pyramid.traversal.resource_path_tuple` does. In particular, the leading empty string is not present in the tuple it returns, unlike tuples returned by :func:`pyramid.traversal.resource_path_tuple`. As a result, tuples generated by ``traversal_path`` are not resolveable by the :func:`pyramid.traversal.find_resource` API. ``traversal_path`` is a function mostly used by the internals of :app:`Pyramid` and by people writing their own traversal machinery, as opposed to users writing applications in :app:`Pyramid`. """ if isinstance(path, unicode): path = path.encode('ascii') path = path.strip('/') clean = [] for segment in path.split('/'): segment = urllib.unquote(segment) # deal with spaces in path segment if not segment or segment=='.': continue elif segment == '..': del clean[-1] else: try: segment = segment.decode('utf-8') except UnicodeDecodeError, e: raise URLDecodeError( e.encoding, e.object, e.start, e.end, e.reason ) clean.append(segment) return tuple(clean)
_segment_cache = {}
[docs]def quote_path_segment(segment): """ Return a quoted representation of a 'path segment' (such as the string ``__name__`` attribute of a resource) as a string. If the ``segment`` passed in is a unicode object, it is converted to a UTF-8 string, then it is URL-quoted using Python's ``urllib.quote``. If the ``segment`` passed in is a string, it is URL-quoted using Python's :mod:`urllib.quote`. If the segment passed in is not a string or unicode object, an error will be raised. The return value of ``quote_path_segment`` is always a string, never Unicode. .. note:: The return value for each segment passed to this function is cached in a module-scope dictionary for speed: the cached version is returned when possible rather than recomputing the quoted version. No cache emptying is ever done for the lifetime of an application, however. If you pass arbitrary user-supplied strings to this function (as opposed to some bounded set of values from a 'working set' known to your application), it may become a memory leak. """ # The bit of this code that deals with ``_segment_cache`` is an # optimization: we cache all the computation of URL path segments # in this module-scope dictionary with the original string (or # unicode value) as the key, so we can look it up later without # needing to reencode or re-url-quote it try: return _segment_cache[segment] except KeyError: if segment.__class__ is unicode: # isinstance slighly slower (~15%) result = url_quote(segment.encode('utf-8')) else: result = url_quote(segment) # we don't need a lock to mutate _segment_cache, as the below # will generate exactly one Python bytecode (STORE_SUBSCR) _segment_cache[segment] = result return result
class ResourceTreeTraverser(object): """ A resource tree traverser that should be used (for speed) when every resource in the tree supplies a ``__name__`` and ``__parent__`` attribute (ie. every resource in the tree is :term:`location` aware) .""" implements(ITraverser) VIEW_SELECTOR = '@@' def __init__(self, root): self.root = root def __call__(self, request): try: environ = request.environ except AttributeError: # In BFG 1.0 and before, this API expected an environ # rather than a request; some bit of code may still be # passing us an environ. If so, deal. environ = request if 'bfg.routes.matchdict' in environ: matchdict = environ['bfg.routes.matchdict'] path = matchdict.get('traverse', '/') if hasattr(path, '__iter__'): # this is a *traverse stararg (not a :traverse) path = '/'.join([quote_path_segment(x) for x in path]) or '/' subpath = matchdict.get('subpath', ()) if not hasattr(subpath, '__iter__'): # this is not a *subpath stararg (just a :subpath) subpath = traversal_path(subpath) else: # this request did not match a route subpath = () try: path = environ['PATH_INFO'] or '/' except KeyError: path = '/' if VH_ROOT_KEY in environ: vroot_path = environ[VH_ROOT_KEY] vroot_tuple = traversal_path(vroot_path) vpath = vroot_path + path vroot_idx = len(vroot_tuple) -1 else: vroot_tuple = () vpath = path vroot_idx = -1 root = self.root ob = vroot = root if vpath == '/' or (not vpath): # prevent a call to traversal_path if we know it's going # to return the empty tuple vpath_tuple = () else: # we do dead reckoning here via tuple slicing instead of # pushing and popping temporary lists for speed purposes # and this hurts readability; apologies i = 0 view_selector = self.VIEW_SELECTOR vpath_tuple = traversal_path(vpath) for segment in vpath_tuple: if segment[:2] == view_selector: return {'context':ob, 'view_name':segment[2:], 'subpath':vpath_tuple[i+1:], 'traversed':vpath_tuple[:vroot_idx+i+1], 'virtual_root':vroot, 'virtual_root_path':vroot_tuple, 'root':root} try: getitem = ob.__getitem__ except AttributeError: return {'context':ob, 'view_name':segment, 'subpath':vpath_tuple[i+1:], 'traversed':vpath_tuple[:vroot_idx+i+1], 'virtual_root':vroot, 'virtual_root_path':vroot_tuple, 'root':root} try: next = getitem(segment) except KeyError: return {'context':ob, 'view_name':segment, 'subpath':vpath_tuple[i+1:], 'traversed':vpath_tuple[:vroot_idx+i+1], 'virtual_root':vroot, 'virtual_root_path':vroot_tuple, 'root':root} if i == vroot_idx: vroot = next ob = next i += 1 return {'context':ob, 'view_name':u'', 'subpath':subpath, 'traversed':vpath_tuple, 'virtual_root':vroot, 'virtual_root_path':vroot_tuple, 'root':root} ModelGraphTraverser = ResourceTreeTraverser # b/w compat, not API, used in wild class TraversalContextURL(object): """ The IContextURL adapter used to generate URLs for a resource in a resource tree""" implements(IContextURL) vroot_varname = VH_ROOT_KEY def __init__(self, context, request): self.context = context self.request = request def virtual_root(self): environ = self.request.environ vroot_varname = self.vroot_varname if vroot_varname in environ: return find_resource(self.context, environ[vroot_varname]) # shortcut instead of using find_root; we probably already # have it on the request try: return self.request.root except AttributeError: return find_root(self.context) def __call__(self): """ Generate a URL based on the :term:`lineage` of a :term:`resource` object that is ``self.context``. If any resource in the context lineage has a Unicode name, it will be converted to a UTF-8 string before being attached to the URL. If a ``HTTP_X_VHM_ROOT`` key is present in the WSGI environment, its value will be treated as a 'virtual root path': the path of the URL generated by this will be left-stripped of this virtual root path value. """ resource = self.context physical_path = resource_path(resource) if physical_path != '/': physical_path = physical_path + '/' virtual_path = physical_path request = self.request environ = request.environ vroot_varname = self.vroot_varname vroot_path = environ.get(vroot_varname) # if the physical path starts with the virtual root path, trim it out # of the virtual path if vroot_path is not None: if physical_path.startswith(vroot_path): virtual_path = physical_path[len(vroot_path):] local_url = getattr(resource, '__resource_url__', None) if local_url is not None: result = local_url(request, {'virtual_path':virtual_path, 'physical_path':physical_path}, ) if result is not None: # allow it to punt by returning ``None`` return result app_url = request.application_url # never ends in a slash return app_url + virtual_path @lru_cache(1000) def _join_path_tuple(tuple): return tuple and '/'.join([quote_path_segment(x) for x in tuple]) or '/' class DefaultRootFactory: __parent__ = None __name__ = None def __init__(self, request): matchdict = request.matchdict # provide backwards compatibility for applications which # used routes (at least apps without any custom "context # factory") in BFG 0.9.X and before if matchdict is not None: self.__dict__.update(matchdict)

This Page