Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/tornado/routing.py: 28%
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1# Copyright 2015 The Tornado Authors
2#
3# Licensed under the Apache License, Version 2.0 (the "License"); you may
4# not use this file except in compliance with the License. You may obtain
5# a copy of the License at
6#
7# http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12# License for the specific language governing permissions and limitations
13# under the License.
15"""Flexible routing implementation.
17Tornado routes HTTP requests to appropriate handlers using `Router`
18class implementations. The `tornado.web.Application` class is a
19`Router` implementation and may be used directly, or the classes in
20this module may be used for additional flexibility. The `RuleRouter`
21class can match on more criteria than `.Application`, or the `Router`
22interface can be subclassed for maximum customization.
24`Router` interface extends `~.httputil.HTTPServerConnectionDelegate`
25to provide additional routing capabilities. This also means that any
26`Router` implementation can be used directly as a ``request_callback``
27for `~.httpserver.HTTPServer` constructor.
29`Router` subclass must implement a ``find_handler`` method to provide
30a suitable `~.httputil.HTTPMessageDelegate` instance to handle the
31request:
33.. code-block:: python
35 class CustomRouter(Router):
36 def find_handler(self, request, **kwargs):
37 # some routing logic providing a suitable HTTPMessageDelegate instance
38 return MessageDelegate(request.connection)
40 class MessageDelegate(HTTPMessageDelegate):
41 def __init__(self, connection):
42 self.connection = connection
44 def finish(self):
45 self.connection.write_headers(
46 ResponseStartLine("HTTP/1.1", 200, "OK"),
47 HTTPHeaders({"Content-Length": "2"}),
48 b"OK")
49 self.connection.finish()
51 router = CustomRouter()
52 server = HTTPServer(router)
54The main responsibility of `Router` implementation is to provide a
55mapping from a request to `~.httputil.HTTPMessageDelegate` instance
56that will handle this request. In the example above we can see that
57routing is possible even without instantiating an `~.web.Application`.
59For routing to `~.web.RequestHandler` implementations we need an
60`~.web.Application` instance. `~.web.Application.get_handler_delegate`
61provides a convenient way to create `~.httputil.HTTPMessageDelegate`
62for a given request and `~.web.RequestHandler`.
64Here is a simple example of how we can we route to
65`~.web.RequestHandler` subclasses by HTTP method:
67.. code-block:: python
69 resources = {}
71 class GetResource(RequestHandler):
72 def get(self, path):
73 if path not in resources:
74 raise HTTPError(404)
76 self.finish(resources[path])
78 class PostResource(RequestHandler):
79 def post(self, path):
80 resources[path] = self.request.body
82 class HTTPMethodRouter(Router):
83 def __init__(self, app):
84 self.app = app
86 def find_handler(self, request, **kwargs):
87 handler = GetResource if request.method == "GET" else PostResource
88 return self.app.get_handler_delegate(request, handler, path_args=[request.path])
90 router = HTTPMethodRouter(Application())
91 server = HTTPServer(router)
93`ReversibleRouter` interface adds the ability to distinguish between
94the routes and reverse them to the original urls using route's name
95and additional arguments. `~.web.Application` is itself an
96implementation of `ReversibleRouter` class.
98`RuleRouter` and `ReversibleRuleRouter` are implementations of
99`Router` and `ReversibleRouter` interfaces and can be used for
100creating rule-based routing configurations.
102Rules are instances of `Rule` class. They contain a `Matcher`, which
103provides the logic for determining whether the rule is a match for a
104particular request and a target, which can be one of the following.
1061) An instance of `~.httputil.HTTPServerConnectionDelegate`:
108.. code-block:: python
110 router = RuleRouter([
111 Rule(PathMatches("/handler"), ConnectionDelegate()),
112 # ... more rules
113 ])
115 class ConnectionDelegate(HTTPServerConnectionDelegate):
116 def start_request(self, server_conn, request_conn):
117 return MessageDelegate(request_conn)
1192) A callable accepting a single argument of `~.httputil.HTTPServerRequest` type:
121.. code-block:: python
123 router = RuleRouter([
124 Rule(PathMatches("/callable"), request_callable)
125 ])
127 def request_callable(request):
128 request.write(b"HTTP/1.1 200 OK\\r\\nContent-Length: 2\\r\\n\\r\\nOK")
129 request.finish()
1313) Another `Router` instance:
133.. code-block:: python
135 router = RuleRouter([
136 Rule(PathMatches("/router.*"), CustomRouter())
137 ])
139Of course a nested `RuleRouter` or a `~.web.Application` is allowed:
141.. code-block:: python
143 router = RuleRouter([
144 Rule(HostMatches("example.com"), RuleRouter([
145 Rule(PathMatches("/app1/.*"), Application([(r"/app1/handler", Handler)])),
146 ]))
147 ])
149 server = HTTPServer(router)
151In the example below `RuleRouter` is used to route between applications:
153.. code-block:: python
155 app1 = Application([
156 (r"/app1/handler", Handler1),
157 # other handlers ...
158 ])
160 app2 = Application([
161 (r"/app2/handler", Handler2),
162 # other handlers ...
163 ])
165 router = RuleRouter([
166 Rule(PathMatches("/app1.*"), app1),
167 Rule(PathMatches("/app2.*"), app2)
168 ])
170 server = HTTPServer(router)
172For more information on application-level routing see docs for `~.web.Application`.
174.. versionadded:: 4.5
176"""
178import re
179from functools import partial
181from tornado import httputil
182from tornado.httpserver import _CallableAdapter
183from tornado.escape import url_escape, url_unescape, utf8
184from tornado.log import app_log
185from tornado.util import basestring_type, import_object, re_unescape, unicode_type
187from typing import Any, Union, Optional, Awaitable, List, Dict, Pattern, Tuple, overload
190class Router(httputil.HTTPServerConnectionDelegate):
191 """Abstract router interface."""
193 def find_handler(
194 self, request: httputil.HTTPServerRequest, **kwargs: Any
195 ) -> Optional[httputil.HTTPMessageDelegate]:
196 """Must be implemented to return an appropriate instance of `~.httputil.HTTPMessageDelegate`
197 that can serve the request.
198 Routing implementations may pass additional kwargs to extend the routing logic.
200 :arg httputil.HTTPServerRequest request: current HTTP request.
201 :arg kwargs: additional keyword arguments passed by routing implementation.
202 :returns: an instance of `~.httputil.HTTPMessageDelegate` that will be used to
203 process the request.
204 """
205 raise NotImplementedError()
207 def start_request(
208 self, server_conn: object, request_conn: httputil.HTTPConnection
209 ) -> httputil.HTTPMessageDelegate:
210 return _RoutingDelegate(self, server_conn, request_conn)
213class ReversibleRouter(Router):
214 """Abstract router interface for routers that can handle named routes
215 and support reversing them to original urls.
216 """
218 def reverse_url(self, name: str, *args: Any) -> Optional[str]:
219 """Returns url string for a given route name and arguments
220 or ``None`` if no match is found.
222 :arg str name: route name.
223 :arg args: url parameters.
224 :returns: parametrized url string for a given route name (or ``None``).
225 """
226 raise NotImplementedError()
229class _RoutingDelegate(httputil.HTTPMessageDelegate):
230 def __init__(
231 self, router: Router, server_conn: object, request_conn: httputil.HTTPConnection
232 ) -> None:
233 self.server_conn = server_conn
234 self.request_conn = request_conn
235 self.delegate = None # type: Optional[httputil.HTTPMessageDelegate]
236 self.router = router # type: Router
238 def headers_received(
239 self,
240 start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
241 headers: httputil.HTTPHeaders,
242 ) -> Optional[Awaitable[None]]:
243 assert isinstance(start_line, httputil.RequestStartLine)
244 request = httputil.HTTPServerRequest(
245 connection=self.request_conn,
246 server_connection=self.server_conn,
247 start_line=start_line,
248 headers=headers,
249 )
251 self.delegate = self.router.find_handler(request)
252 if self.delegate is None:
253 app_log.debug(
254 "Delegate for %s %s request not found",
255 start_line.method,
256 start_line.path,
257 )
258 self.delegate = _DefaultMessageDelegate(self.request_conn)
260 return self.delegate.headers_received(start_line, headers)
262 def data_received(self, chunk: bytes) -> Optional[Awaitable[None]]:
263 assert self.delegate is not None
264 return self.delegate.data_received(chunk)
266 def finish(self) -> None:
267 assert self.delegate is not None
268 self.delegate.finish()
270 def on_connection_close(self) -> None:
271 assert self.delegate is not None
272 self.delegate.on_connection_close()
275class _DefaultMessageDelegate(httputil.HTTPMessageDelegate):
276 def __init__(self, connection: httputil.HTTPConnection) -> None:
277 self.connection = connection
279 def finish(self) -> None:
280 self.connection.write_headers(
281 httputil.ResponseStartLine("HTTP/1.1", 404, "Not Found"),
282 httputil.HTTPHeaders(),
283 )
284 self.connection.finish()
287# _RuleList can either contain pre-constructed Rules or a sequence of
288# arguments to be passed to the Rule constructor.
289_RuleList = List[
290 Union[
291 "Rule",
292 List[Any], # Can't do detailed typechecking of lists.
293 Tuple[Union[str, "Matcher"], Any],
294 Tuple[Union[str, "Matcher"], Any, Dict[str, Any]],
295 Tuple[Union[str, "Matcher"], Any, Dict[str, Any], str],
296 ]
297]
300class RuleRouter(Router):
301 """Rule-based router implementation."""
303 def __init__(self, rules: Optional[_RuleList] = None) -> None:
304 """Constructs a router from an ordered list of rules::
306 RuleRouter([
307 Rule(PathMatches("/handler"), Target),
308 # ... more rules
309 ])
311 You can also omit explicit `Rule` constructor and use tuples of arguments::
313 RuleRouter([
314 (PathMatches("/handler"), Target),
315 ])
317 `PathMatches` is a default matcher, so the example above can be simplified::
319 RuleRouter([
320 ("/handler", Target),
321 ])
323 In the examples above, ``Target`` can be a nested `Router` instance, an instance of
324 `~.httputil.HTTPServerConnectionDelegate` or an old-style callable,
325 accepting a request argument.
327 :arg rules: a list of `Rule` instances or tuples of `Rule`
328 constructor arguments.
329 """
330 self.rules = [] # type: List[Rule]
331 if rules:
332 self.add_rules(rules)
334 def add_rules(self, rules: _RuleList) -> None:
335 """Appends new rules to the router.
337 :arg rules: a list of Rule instances (or tuples of arguments, which are
338 passed to Rule constructor).
339 """
340 for rule in rules:
341 if isinstance(rule, (tuple, list)):
342 assert len(rule) in (2, 3, 4)
343 if isinstance(rule[0], basestring_type):
344 rule = Rule(PathMatches(rule[0]), *rule[1:])
345 else:
346 rule = Rule(*rule)
348 self.rules.append(self.process_rule(rule))
350 def process_rule(self, rule: "Rule") -> "Rule":
351 """Override this method for additional preprocessing of each rule.
353 :arg Rule rule: a rule to be processed.
354 :returns: the same or modified Rule instance.
355 """
356 return rule
358 def find_handler(
359 self, request: httputil.HTTPServerRequest, **kwargs: Any
360 ) -> Optional[httputil.HTTPMessageDelegate]:
361 for rule in self.rules:
362 target_params = rule.matcher.match(request)
363 if target_params is not None:
364 if rule.target_kwargs:
365 target_params["target_kwargs"] = rule.target_kwargs
367 delegate = self.get_target_delegate(
368 rule.target, request, **target_params
369 )
371 if delegate is not None:
372 return delegate
374 return None
376 def get_target_delegate(
377 self, target: Any, request: httputil.HTTPServerRequest, **target_params: Any
378 ) -> Optional[httputil.HTTPMessageDelegate]:
379 """Returns an instance of `~.httputil.HTTPMessageDelegate` for a
380 Rule's target. This method is called by `~.find_handler` and can be
381 extended to provide additional target types.
383 :arg target: a Rule's target.
384 :arg httputil.HTTPServerRequest request: current request.
385 :arg target_params: additional parameters that can be useful
386 for `~.httputil.HTTPMessageDelegate` creation.
387 """
388 if isinstance(target, Router):
389 return target.find_handler(request, **target_params)
391 elif isinstance(target, httputil.HTTPServerConnectionDelegate):
392 assert request.connection is not None
393 return target.start_request(request.server_connection, request.connection)
395 elif callable(target):
396 assert request.connection is not None
397 return _CallableAdapter(
398 partial(target, **target_params), request.connection
399 )
401 return None
404class ReversibleRuleRouter(ReversibleRouter, RuleRouter):
405 """A rule-based router that implements ``reverse_url`` method.
407 Each rule added to this router may have a ``name`` attribute that can be
408 used to reconstruct an original uri. The actual reconstruction takes place
409 in a rule's matcher (see `Matcher.reverse`).
410 """
412 def __init__(self, rules: Optional[_RuleList] = None) -> None:
413 self.named_rules = {} # type: Dict[str, Any]
414 super().__init__(rules)
416 def process_rule(self, rule: "Rule") -> "Rule":
417 rule = super().process_rule(rule)
419 if rule.name:
420 if rule.name in self.named_rules:
421 app_log.warning(
422 "Multiple handlers named %s; replacing previous value", rule.name
423 )
424 self.named_rules[rule.name] = rule
426 return rule
428 def reverse_url(self, name: str, *args: Any) -> Optional[str]:
429 if name in self.named_rules:
430 return self.named_rules[name].matcher.reverse(*args)
432 for rule in self.rules:
433 if isinstance(rule.target, ReversibleRouter):
434 reversed_url = rule.target.reverse_url(name, *args)
435 if reversed_url is not None:
436 return reversed_url
438 return None
441class Rule(object):
442 """A routing rule."""
444 def __init__(
445 self,
446 matcher: "Matcher",
447 target: Any,
448 target_kwargs: Optional[Dict[str, Any]] = None,
449 name: Optional[str] = None,
450 ) -> None:
451 """Constructs a Rule instance.
453 :arg Matcher matcher: a `Matcher` instance used for determining
454 whether the rule should be considered a match for a specific
455 request.
456 :arg target: a Rule's target (typically a ``RequestHandler`` or
457 `~.httputil.HTTPServerConnectionDelegate` subclass or even a nested `Router`,
458 depending on routing implementation).
459 :arg dict target_kwargs: a dict of parameters that can be useful
460 at the moment of target instantiation (for example, ``status_code``
461 for a ``RequestHandler`` subclass). They end up in
462 ``target_params['target_kwargs']`` of `RuleRouter.get_target_delegate`
463 method.
464 :arg str name: the name of the rule that can be used to find it
465 in `ReversibleRouter.reverse_url` implementation.
466 """
467 if isinstance(target, str):
468 # import the Module and instantiate the class
469 # Must be a fully qualified name (module.ClassName)
470 target = import_object(target)
472 self.matcher = matcher # type: Matcher
473 self.target = target
474 self.target_kwargs = target_kwargs if target_kwargs else {}
475 self.name = name
477 def reverse(self, *args: Any) -> Optional[str]:
478 return self.matcher.reverse(*args)
480 def __repr__(self) -> str:
481 return "%s(%r, %s, kwargs=%r, name=%r)" % (
482 self.__class__.__name__,
483 self.matcher,
484 self.target,
485 self.target_kwargs,
486 self.name,
487 )
490class Matcher(object):
491 """Represents a matcher for request features."""
493 def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
494 """Matches current instance against the request.
496 :arg httputil.HTTPServerRequest request: current HTTP request
497 :returns: a dict of parameters to be passed to the target handler
498 (for example, ``handler_kwargs``, ``path_args``, ``path_kwargs``
499 can be passed for proper `~.web.RequestHandler` instantiation).
500 An empty dict is a valid (and common) return value to indicate a match
501 when the argument-passing features are not used.
502 ``None`` must be returned to indicate that there is no match."""
503 raise NotImplementedError()
505 def reverse(self, *args: Any) -> Optional[str]:
506 """Reconstructs full url from matcher instance and additional arguments."""
507 return None
510class AnyMatches(Matcher):
511 """Matches any request."""
513 def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
514 return {}
517class HostMatches(Matcher):
518 """Matches requests from hosts specified by ``host_pattern`` regex."""
520 def __init__(self, host_pattern: Union[str, Pattern]) -> None:
521 if isinstance(host_pattern, basestring_type):
522 if not host_pattern.endswith("$"):
523 host_pattern += "$"
524 self.host_pattern = re.compile(host_pattern)
525 else:
526 self.host_pattern = host_pattern
528 def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
529 if self.host_pattern.match(request.host_name):
530 return {}
532 return None
535class DefaultHostMatches(Matcher):
536 """Matches requests from host that is equal to application's default_host.
537 Always returns no match if ``X-Real-Ip`` header is present.
538 """
540 def __init__(self, application: Any, host_pattern: Pattern) -> None:
541 self.application = application
542 self.host_pattern = host_pattern
544 def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
545 # Look for default host if not behind load balancer (for debugging)
546 if "X-Real-Ip" not in request.headers:
547 if self.host_pattern.match(self.application.default_host):
548 return {}
549 return None
552class PathMatches(Matcher):
553 """Matches requests with paths specified by ``path_pattern`` regex."""
555 def __init__(self, path_pattern: Union[str, Pattern]) -> None:
556 if isinstance(path_pattern, basestring_type):
557 if not path_pattern.endswith("$"):
558 path_pattern += "$"
559 self.regex = re.compile(path_pattern)
560 else:
561 self.regex = path_pattern
563 assert len(self.regex.groupindex) in (0, self.regex.groups), (
564 "groups in url regexes must either be all named or all "
565 "positional: %r" % self.regex.pattern
566 )
568 self._path, self._group_count = self._find_groups()
570 def match(self, request: httputil.HTTPServerRequest) -> Optional[Dict[str, Any]]:
571 match = self.regex.match(request.path)
572 if match is None:
573 return None
574 if not self.regex.groups:
575 return {}
577 path_args = [] # type: List[bytes]
578 path_kwargs = {} # type: Dict[str, bytes]
580 # Pass matched groups to the handler. Since
581 # match.groups() includes both named and
582 # unnamed groups, we want to use either groups
583 # or groupdict but not both.
584 if self.regex.groupindex:
585 path_kwargs = dict(
586 (str(k), _unquote_or_none(v)) for (k, v) in match.groupdict().items()
587 )
588 else:
589 path_args = [_unquote_or_none(s) for s in match.groups()]
591 return dict(path_args=path_args, path_kwargs=path_kwargs)
593 def reverse(self, *args: Any) -> Optional[str]:
594 if self._path is None:
595 raise ValueError("Cannot reverse url regex " + self.regex.pattern)
596 assert len(args) == self._group_count, (
597 "required number of arguments " "not found"
598 )
599 if not len(args):
600 return self._path
601 converted_args = []
602 for a in args:
603 if not isinstance(a, (unicode_type, bytes)):
604 a = str(a)
605 converted_args.append(url_escape(utf8(a), plus=False))
606 return self._path % tuple(converted_args)
608 def _find_groups(self) -> Tuple[Optional[str], Optional[int]]:
609 """Returns a tuple (reverse string, group count) for a url.
611 For example: Given the url pattern /([0-9]{4})/([a-z-]+)/, this method
612 would return ('/%s/%s/', 2).
613 """
614 pattern = self.regex.pattern
615 if pattern.startswith("^"):
616 pattern = pattern[1:]
617 if pattern.endswith("$"):
618 pattern = pattern[:-1]
620 if self.regex.groups != pattern.count("("):
621 # The pattern is too complicated for our simplistic matching,
622 # so we can't support reversing it.
623 return None, None
625 pieces = []
626 for fragment in pattern.split("("):
627 if ")" in fragment:
628 paren_loc = fragment.index(")")
629 if paren_loc >= 0:
630 try:
631 unescaped_fragment = re_unescape(fragment[paren_loc + 1 :])
632 except ValueError:
633 # If we can't unescape part of it, we can't
634 # reverse this url.
635 return (None, None)
636 pieces.append("%s" + unescaped_fragment)
637 else:
638 try:
639 unescaped_fragment = re_unescape(fragment)
640 except ValueError:
641 # If we can't unescape part of it, we can't
642 # reverse this url.
643 return (None, None)
644 pieces.append(unescaped_fragment)
646 return "".join(pieces), self.regex.groups
649class URLSpec(Rule):
650 """Specifies mappings between URLs and handlers.
652 .. versionchanged: 4.5
653 `URLSpec` is now a subclass of a `Rule` with `PathMatches` matcher and is preserved for
654 backwards compatibility.
655 """
657 def __init__(
658 self,
659 pattern: Union[str, Pattern],
660 handler: Any,
661 kwargs: Optional[Dict[str, Any]] = None,
662 name: Optional[str] = None,
663 ) -> None:
664 """Parameters:
666 * ``pattern``: Regular expression to be matched. Any capturing
667 groups in the regex will be passed in to the handler's
668 get/post/etc methods as arguments (by keyword if named, by
669 position if unnamed. Named and unnamed capturing groups
670 may not be mixed in the same rule).
672 * ``handler``: `~.web.RequestHandler` subclass to be invoked.
674 * ``kwargs`` (optional): A dictionary of additional arguments
675 to be passed to the handler's constructor.
677 * ``name`` (optional): A name for this handler. Used by
678 `~.web.Application.reverse_url`.
680 """
681 matcher = PathMatches(pattern)
682 super().__init__(matcher, handler, kwargs, name)
684 self.regex = matcher.regex
685 self.handler_class = self.target
686 self.kwargs = kwargs
688 def __repr__(self) -> str:
689 return "%s(%r, %s, kwargs=%r, name=%r)" % (
690 self.__class__.__name__,
691 self.regex.pattern,
692 self.handler_class,
693 self.kwargs,
694 self.name,
695 )
698@overload
699def _unquote_or_none(s: str) -> bytes:
700 pass
703@overload # noqa: F811
704def _unquote_or_none(s: None) -> None:
705 pass
708def _unquote_or_none(s: Optional[str]) -> Optional[bytes]: # noqa: F811
709 """None-safe wrapper around url_unescape to handle unmatched optional
710 groups correctly.
712 Note that args are passed as bytes so the handler can decide what
713 encoding to use.
714 """
715 if s is None:
716 return s
717 return url_unescape(s, encoding=None, plus=False)