"""CherryPy dispatchers. A 'dispatcher' is the object which looks up the 'page handler' callable and collects config for the current request based on the path_info, other request attributes, and the application architecture. The core calls the dispatcher as early as possible, passing it a 'path_info' argument. The default dispatcher discovers the page handler by matching path_info to a hierarchical arrangement of objects, starting at request.app.root. """ import string import sys import types try: classtype = (type, type) except AttributeError: classtype = type import cherrypy from cherrypy._cpcompat import set class PageHandler(object): """Callable which sets response.body.""" def __init__(self, callable, *args, **kwargs): self.callable = callable self.args = args self.kwargs = kwargs def get_args(self): return cherrypy.serving.request.args def set_args(self, args): cherrypy.serving.request.args = args return cherrypy.serving.request.args args = property( get_args, set_args, doc="The ordered args should be accessible from post dispatch hooks" ) def get_kwargs(self): return cherrypy.serving.request.kwargs def set_kwargs(self, kwargs): cherrypy.serving.request.kwargs = kwargs return cherrypy.serving.request.kwargs kwargs = property( get_kwargs, set_kwargs, doc="The named kwargs should be accessible from post dispatch hooks" ) def __call__(self): try: return self.callable(*self.args, **self.kwargs) except TypeError: x = sys.exc_info()[1] try: test_callable_spec(self.callable, self.args, self.kwargs) except cherrypy.HTTPError: raise sys.exc_info()[1] except: raise x raise def test_callable_spec(callable, callable_args, callable_kwargs): """ Inspect callable and test to see if the given args are suitable for it. When an error occurs during the handler's invoking stage there are 2 erroneous cases: 1. Too many parameters passed to a function which doesn't define one of *args or **kwargs. 2. Too little parameters are passed to the function. There are 3 sources of parameters to a cherrypy handler. 1. query string parameters are passed as keyword parameters to the handler. 2. body parameters are also passed as keyword parameters. 3. when partial matching occurs, the final path atoms are passed as positional args. Both the query string and path atoms are part of the URI. If they are incorrect, then a 404 Not Found should be raised. Conversely the body parameters are part of the request; if they are invalid a 400 Bad Request. """ show_mismatched_params = getattr( cherrypy.serving.request, 'show_mismatched_params', False) try: (args, varargs, varkw, defaults) = getargspec(callable) except TypeError: if isinstance(callable, object) and hasattr(callable, '__call__'): (args, varargs, varkw, defaults) = getargspec(callable.__call__) else: # If it wasn't one of our own types, re-raise # the original error raise if args and args[0] == 'self': args = args[1:] arg_usage = dict([(arg, 0,) for arg in args]) vararg_usage = 0 varkw_usage = 0 extra_kwargs = set() for i, value in enumerate(callable_args): try: arg_usage[args[i]] += 1 except IndexError: vararg_usage += 1 for key in list(callable_kwargs.keys()): try: arg_usage[key] += 1 except KeyError: varkw_usage += 1 extra_kwargs.add(key) # figure out which args have defaults. args_with_defaults = args[-len(defaults or []):] for i, val in enumerate(defaults or []): # Defaults take effect only when the arg hasn't been used yet. if arg_usage[args_with_defaults[i]] == 0: arg_usage[args_with_defaults[i]] += 1 missing_args = [] multiple_args = [] for key, usage in list(arg_usage.items()): if usage == 0: missing_args.append(key) elif usage > 1: multiple_args.append(key) if missing_args: # In the case where the method allows body arguments # there are 3 potential errors: # 1. not enough query string parameters -> 404 # 2. not enough body parameters -> 400 # 3. not enough path parts (partial matches) -> 404 # # We can't actually tell which case it is, # so I'm raising a 404 because that covers 2/3 of the # possibilities # # In the case where the method does not allow body # arguments it's definitely a 404. message = None if show_mismatched_params: message = "Missing parameters: %s" % ",".join(missing_args) raise cherrypy.HTTPError(404, message=message) # the extra positional arguments come from the path - 404 Not Found if not varargs and vararg_usage > 0: raise cherrypy.HTTPError(404) body_params = cherrypy.serving.request.body.params or {} body_params = set(body_params.keys()) qs_params = set(callable_kwargs.keys()) - body_params if multiple_args: if qs_params.intersection(set(multiple_args)): # If any of the multiple parameters came from the query string then # it's a 404 Not Found error = 404 else: # Otherwise it's a 400 Bad Request error = 400 message = None if show_mismatched_params: message = "Multiple values for parameters: "\ "%s" % ",".join(multiple_args) raise cherrypy.HTTPError(error, message=message) if not varkw and varkw_usage > 0: # If there were extra query string parameters, it's a 404 Not Found extra_qs_params = set(qs_params).intersection(extra_kwargs) if extra_qs_params: message = None if show_mismatched_params: message = "Unexpected query string "\ "parameters: %s" % ", ".join(extra_qs_params) raise cherrypy.HTTPError(404, message=message) # If there were any extra body parameters, it's a 400 Not Found extra_body_params = set(body_params).intersection(extra_kwargs) if extra_body_params: message = None if show_mismatched_params: message = "Unexpected body parameters: "\ "%s" % ", ".join(extra_body_params) raise cherrypy.HTTPError(400, message=message) try: import inspect except ImportError: test_callable_spec = lambda callable, args, kwargs: None else: getargspec = inspect.getargspec # Python 3 requires using getfullargspec if keyword-only arguments are present if hasattr(inspect, 'getfullargspec'): def getargspec(callable): return inspect.getfullargspec(callable)[:4] class LateParamPageHandler(PageHandler): """When passing cherrypy.request.params to the page handler, we do not want to capture that dict too early; we want to give tools like the decoding tool a chance to modify the params dict in-between the lookup of the handler and the actual calling of the handler. This subclass takes that into account, and allows request.params to be 'bound late' (it's more complicated than that, but that's the effect). """ def _get_kwargs(self): kwargs = cherrypy.serving.request.params.copy() if self._kwargs: kwargs.update(self._kwargs) return kwargs def _set_kwargs(self, kwargs): cherrypy.serving.request.kwargs = kwargs self._kwargs = kwargs kwargs = property(_get_kwargs, _set_kwargs, doc='page handler kwargs (with ' 'cherrypy.request.params copied in)') if sys.version_info < (3, 0): punctuation_to_underscores = string.maketrans( string.punctuation, '_' * len(string.punctuation)) def validate_translator(t): if not isinstance(t, str) or len(t) != 256: raise ValueError( "The translate argument must be a str of len 256.") else: punctuation_to_underscores = str.maketrans( string.punctuation, '_' * len(string.punctuation)) def validate_translator(t): if not isinstance(t, dict): raise ValueError("The translate argument must be a dict.") class Dispatcher(object): """CherryPy Dispatcher which walks a tree of objects to find a handler. The tree is rooted at cherrypy.request.app.root, and each hierarchical component in the path_info argument is matched to a corresponding nested attribute of the root object. Matching handlers must have an 'exposed' attribute which evaluates to True. The special method name "index" matches a URI which ends in a slash ("/"). The special method name "default" may match a portion of the path_info (but only when no longer substring of the path_info matches some other object). This is the default, built-in dispatcher for CherryPy. """ dispatch_method_name = '_cp_dispatch' """ The name of the dispatch method that nodes may optionally implement to provide their own dynamic dispatch algorithm. """ def __init__(self, dispatch_method_name=None, translate=punctuation_to_underscores): validate_translator(translate) self.translate = translate if dispatch_method_name: self.dispatch_method_name = dispatch_method_name def __call__(self, path_info): """Set handler and config for the current request.""" request = cherrypy.serving.request func, vpath = self.find_handler(path_info) if func: # Decode any leftover %2F in the virtual_path atoms. vpath = [x.replace("%2F", "/") for x in vpath] request.handler = LateParamPageHandler(func, *vpath) else: request.handler = cherrypy.NotFound() def find_handler(self, path): """Return the appropriate page handler, plus any virtual path. This will return two objects. The first will be a callable, which can be used to generate page output. Any parameters from the query string or request body will be sent to that callable as keyword arguments. The callable is found by traversing the application's tree, starting from cherrypy.request.app.root, and matching path components to successive objects in the tree. For example, the URL "/path/to/handler" might return root.path.to.handler. The second object returned will be a list of names which are 'virtual path' components: parts of the URL which are dynamic, and were not used when looking up the handler. These virtual path components are passed to the handler as positional arguments. """ request = cherrypy.serving.request app = request.app root = app.root dispatch_name = self.dispatch_method_name # Get config for the root object/path. fullpath = [x for x in path.strip('/').split('/') if x] + ['index'] fullpath_len = len(fullpath) segleft = fullpath_len nodeconf = {} if hasattr(root, "_cp_config"): nodeconf.update(root._cp_config) if "/" in app.config: nodeconf.update(app.config["/"]) object_trail = [['root', root, nodeconf, segleft]] node = root iternames = fullpath[:] while iternames: name = iternames[0] # map to legal Python identifiers (e.g. replace '.' with '_') objname = name.translate(self.translate) nodeconf = {} subnode = getattr(node, objname, None) pre_len = len(iternames) if subnode is None: dispatch = getattr(node, dispatch_name, None) if dispatch and hasattr(dispatch, '__call__') and not \ getattr(dispatch, 'exposed', False) and \ pre_len > 1: # Don't expose the hidden 'index' token to _cp_dispatch # We skip this if pre_len == 1 since it makes no sense # to call a dispatcher when we have no tokens left. index_name = iternames.pop() subnode = dispatch(vpath=iternames) iternames.append(index_name) else: # We didn't find a path, but keep processing in case there # is a default() handler. iternames.pop(0) else: # We found the path, remove the vpath entry iternames.pop(0) segleft = len(iternames) if segleft > pre_len: # No path segment was removed. Raise an error. raise cherrypy.CherryPyException( "A vpath segment was added. Custom dispatchers may only " + "remove elements. While trying to process " + "{0} in {1}".format(name, fullpath) ) elif segleft == pre_len: # Assume that the handler used the current path segment, but # did not pop it. This allows things like # return getattr(self, vpath[0], None) iternames.pop(0) segleft -= 1 node = subnode if node is not None: # Get _cp_config attached to this node. if hasattr(node, "_cp_config"): nodeconf.update(node._cp_config) # Mix in values from app.config for this path. existing_len = fullpath_len - pre_len if existing_len != 0: curpath = '/' + '/'.join(fullpath[0:existing_len]) else: curpath = '' new_segs = fullpath[fullpath_len - pre_len:fullpath_len - segleft] for seg in new_segs: curpath += '/' + seg if curpath in app.config: nodeconf.update(app.config[curpath]) object_trail.append([name, node, nodeconf, segleft]) def set_conf(): """Collapse all object_trail config into cherrypy.request.config. """ base = cherrypy.config.copy() # Note that we merge the config from each node # even if that node was None. for name, obj, conf, segleft in object_trail: base.update(conf) if 'tools.staticdir.dir' in conf: base['tools.staticdir.section'] = '/' + \ '/'.join(fullpath[0:fullpath_len - segleft]) return base # Try successive objects (reverse order) num_candidates = len(object_trail) - 1 for i in range(num_candidates, -1, -1): name, candidate, nodeconf, segleft = object_trail[i] if candidate is None: continue # Try a "default" method on the current leaf. if hasattr(candidate, "default"): defhandler = candidate.default if getattr(defhandler, 'exposed', False): # Insert any extra _cp_config from the default handler. conf = getattr(defhandler, "_cp_config", {}) object_trail.insert( i + 1, ["default", defhandler, conf, segleft]) request.config = set_conf() # See https://bitbucket.org/cherrypy/cherrypy/issue/613 request.is_index = path.endswith("/") return defhandler, fullpath[fullpath_len - segleft:-1] # Uncomment the next line to restrict positional params to # "default". # if i < num_candidates - 2: continue # Try the current leaf. if getattr(candidate, 'exposed', False): request.config = set_conf() if i == num_candidates: # We found the extra ".index". Mark request so tools # can redirect if path_info has no trailing slash. request.is_index = True else: # We're not at an 'index' handler. Mark request so tools # can redirect if path_info has NO trailing slash. # Note that this also includes handlers which take # positional parameters (virtual paths). request.is_index = False return candidate, fullpath[fullpath_len - segleft:-1] # We didn't find anything request.config = set_conf() return None, [] class MethodDispatcher(Dispatcher): """Additional dispatch based on cherrypy.request.method.upper(). Methods named GET, POST, etc will be called on an exposed class. The method names must be all caps; the appropriate Allow header will be output showing all capitalized method names as allowable HTTP verbs. Note that the containing class must be exposed, not the methods. """ def __call__(self, path_info): """Set handler and config for the current request.""" request = cherrypy.serving.request resource, vpath = self.find_handler(path_info) if resource: # Set Allow header avail = [m for m in dir(resource) if m.isupper()] if "GET" in avail and "HEAD" not in avail: avail.append("HEAD") avail.sort() cherrypy.serving.response.headers['Allow'] = ", ".join(avail) # Find the subhandler meth = request.method.upper() func = getattr(resource, meth, None) if func is None and meth == "HEAD": func = getattr(resource, "GET", None) if func: # Grab any _cp_config on the subhandler. if hasattr(func, "_cp_config"): request.config.update(func._cp_config) # Decode any leftover %2F in the virtual_path atoms. vpath = [x.replace("%2F", "/") for x in vpath] request.handler = LateParamPageHandler(func, *vpath) else: request.handler = cherrypy.HTTPError(405) else: request.handler = cherrypy.NotFound() class RoutesDispatcher(object): """A Routes based dispatcher for CherryPy.""" def __init__(self, full_result=False, **mapper_options): """ Routes dispatcher Set full_result to True if you wish the controller and the action to be passed on to the page handler parameters. By default they won't be. """ import routes self.full_result = full_result self.controllers = {} self.mapper = routes.Mapper(**mapper_options) self.mapper.controller_scan = self.controllers.keys def connect(self, name, route, controller, **kwargs): self.controllers[name] = controller self.mapper.connect(name, route, controller=name, **kwargs) def redirect(self, url): raise cherrypy.HTTPRedirect(url) def __call__(self, path_info): """Set handler and config for the current request.""" func = self.find_handler(path_info) if func: cherrypy.serving.request.handler = LateParamPageHandler(func) else: cherrypy.serving.request.handler = cherrypy.NotFound() def find_handler(self, path_info): """Find the right page handler, and set request.config.""" import routes request = cherrypy.serving.request config = routes.request_config() config.mapper = self.mapper if hasattr(request, 'wsgi_environ'): config.environ = request.wsgi_environ config.host = request.headers.get('Host', None) config.protocol = request.scheme config.redirect = self.redirect result = self.mapper.match(path_info) config.mapper_dict = result params = {} if result: params = result.copy() if not self.full_result: params.pop('controller', None) params.pop('action', None) request.params.update(params) # Get config for the root object/path. request.config = base = cherrypy.config.copy() curpath = "" def merge(nodeconf): if 'tools.staticdir.dir' in nodeconf: nodeconf['tools.staticdir.section'] = curpath or "/" base.update(nodeconf) app = request.app root = app.root if hasattr(root, "_cp_config"): merge(root._cp_config) if "/" in app.config: merge(app.config["/"]) # Mix in values from app.config. atoms = [x for x in path_info.split("/") if x] if atoms: last = atoms.pop() else: last = None for atom in atoms: curpath = "/".join((curpath, atom)) if curpath in app.config: merge(app.config[curpath]) handler = None if result: controller = result.get('controller') controller = self.controllers.get(controller, controller) if controller: if isinstance(controller, classtype): controller = controller() # Get config from the controller. if hasattr(controller, "_cp_config"): merge(controller._cp_config) action = result.get('action') if action is not None: handler = getattr(controller, action, None) # Get config from the handler if hasattr(handler, "_cp_config"): merge(handler._cp_config) else: handler = controller # Do the last path atom here so it can # override the controller's _cp_config. if last: curpath = "/".join((curpath, last)) if curpath in app.config: merge(app.config[curpath]) return handler def XMLRPCDispatcher(next_dispatcher=Dispatcher()): from cherrypy.lib import xmlrpcutil def xmlrpc_dispatch(path_info): path_info = xmlrpcutil.patched_path(path_info) return next_dispatcher(path_info) return xmlrpc_dispatch def VirtualHost(next_dispatcher=Dispatcher(), use_x_forwarded_host=True, **domains): """ Select a different handler based on the Host header. This can be useful when running multiple sites within one CP server. It allows several domains to point to different parts of a single website structure. For example:: http://www.domain.example -> root http://www.domain2.example -> root/domain2/ http://www.domain2.example:443 -> root/secure can be accomplished via the following config:: [/] request.dispatch = cherrypy.dispatch.VirtualHost( **{'www.domain2.example': '/domain2', 'www.domain2.example:443': '/secure', }) next_dispatcher The next dispatcher object in the dispatch chain. The VirtualHost dispatcher adds a prefix to the URL and calls another dispatcher. Defaults to cherrypy.dispatch.Dispatcher(). use_x_forwarded_host If True (the default), any "X-Forwarded-Host" request header will be used instead of the "Host" header. This is commonly added by HTTP servers (such as Apache) when proxying. ``**domains`` A dict of {host header value: virtual prefix} pairs. The incoming "Host" request header is looked up in this dict, and, if a match is found, the corresponding "virtual prefix" value will be prepended to the URL path before calling the next dispatcher. Note that you often need separate entries for "example.com" and "www.example.com". In addition, "Host" headers may contain the port number. """ from cherrypy.lib import httputil def vhost_dispatch(path_info): request = cherrypy.serving.request header = request.headers.get domain = header('Host', '') if use_x_forwarded_host: domain = header("X-Forwarded-Host", domain) prefix = domains.get(domain, "") if prefix: path_info = httputil.urljoin(prefix, path_info) result = next_dispatcher(path_info) # Touch up staticdir config. See # https://bitbucket.org/cherrypy/cherrypy/issue/614. section = request.config.get('tools.staticdir.section') if section: section = section[len(prefix):] request.config['tools.staticdir.section'] = section return result return vhost_dispatch