sanic/sanic/router.py
Eli Uriegas 0a5fa72099 Add logic to make dynamic route merging work
This is by no means the final solution but it's a start in the right
direction. Eventually what needs to happen is we need to reduce the
complexity of the routing. CompsitionView can probably be removed later
on in favor of better Route objects. Also in the next version of sanic
we need to move merge_route and add_parameter out of the add_route logic
and just have them as standalone methods.

The tests should cover everything that we need so that if any changes
are made we can identify regression.
2017-01-29 15:16:07 -06:00

273 lines
9.5 KiB
Python

import re
from collections import defaultdict, namedtuple
from functools import lru_cache
from .config import Config
from .exceptions import NotFound, InvalidUsage
from .views import CompositionView
Route = namedtuple('Route', ['handler', 'methods', 'pattern', 'parameters'])
Parameter = namedtuple('Parameter', ['name', 'cast'])
REGEX_TYPES = {
'string': (str, r'[^/]+'),
'int': (int, r'\d+'),
'number': (float, r'[0-9\\.]+'),
'alpha': (str, r'[A-Za-z]+'),
}
def url_hash(url):
return url.count('/')
class RouteExists(Exception):
pass
class RouteDoesNotExist(Exception):
pass
class Router:
"""
Router supports basic routing with parameters and method checks
Usage:
.. code-block:: python
@sanic.route('/my/url/<my_param>', methods=['GET', 'POST', ...])
def my_route(request, my_param):
do stuff...
or
.. code-block:: python
@sanic.route('/my/url/<my_param:my_type>', methods['GET', 'POST', ...])
def my_route_with_type(request, my_param: my_type):
do stuff...
Parameters will be passed as keyword arguments to the request handling
function. Provided parameters can also have a type by appending :type to
the <parameter>. Given parameter must be able to be type-casted to this.
If no type is provided, a string is expected. A regular expression can
also be passed in as the type. The argument given to the function will
always be a string, independent of the type.
"""
routes_static = None
routes_dynamic = None
routes_always_check = None
def __init__(self):
self.routes_all = {}
self.routes_static = {}
self.routes_dynamic = defaultdict(list)
self.routes_always_check = []
self.hosts = None
def add(self, uri, methods, handler, host=None):
"""
Adds a handler to the route list
:param uri: Path to match
:param methods: Array of accepted method names.
If none are provided, any method is allowed
:param handler: Request handler function.
When executed, it should provide a response object.
:return: Nothing
"""
if host is not None:
# we want to track if there are any
# vhosts on the Router instance so that we can
# default to the behavior without vhosts
if self.hosts is None:
self.hosts = set(host)
else:
if isinstance(host, list):
host = set(host)
self.hosts.add(host)
if isinstance(host, str):
uri = host + uri
else:
for h in host:
self.add(uri, methods, handler, h)
return
# Dict for faster lookups of if method allowed
if methods:
methods = frozenset(methods)
parameters = []
properties = {"unhashable": None}
def add_parameter(match):
# We could receive NAME or NAME:PATTERN
name = match.group(1)
pattern = 'string'
if ':' in name:
name, pattern = name.split(':', 1)
default = (str, pattern)
# Pull from pre-configured types
_type, pattern = REGEX_TYPES.get(pattern, default)
parameter = Parameter(name=name, cast=_type)
parameters.append(parameter)
# Mark the whole route as unhashable if it has the hash key in it
if re.search('(^|[^^]){1}/', pattern):
properties['unhashable'] = True
# Mark the route as unhashable if it matches the hash key
elif re.search(pattern, '/'):
properties['unhashable'] = True
return '({})'.format(pattern)
pattern_string = re.sub(r'<(.+?)>', add_parameter, uri)
pattern = re.compile(r'^{}$'.format(pattern_string))
def merge_route(route, methods, handler):
# merge to the existing route when possible.
if not route.methods or not methods:
# method-unspecified routes are not mergeable.
raise RouteExists(
"Route already registered: {}".format(uri))
elif route.methods.intersection(methods):
# already existing method is not overloadable.
duplicated = methods.intersection(route.methods)
raise RouteExists(
"Route already registered: {} [{}]".format(
uri, ','.join(list(duplicated))))
if isinstance(route.handler, CompositionView):
view = route.handler
else:
view = CompositionView()
view.add(route.methods, route.handler)
view.add(methods, handler)
route = route._replace(
handler=view, methods=methods.union(route.methods))
return route
if parameters:
# TODO: This is too complex, we need to reduce the complexity
if properties['unhashable']:
routes_to_check = self.routes_always_check
ndx, route = self.check_dynamic_route_exists(
pattern, routes_to_check)
else:
routes_to_check = self.routes_dynamic[url_hash(uri)]
ndx, route = self.check_dynamic_route_exists(
pattern, routes_to_check)
if ndx != -1:
# Pop the ndx of the route, no dups of the same route
routes_to_check.pop(ndx)
else:
route = self.routes_all.get(uri)
if route:
route = merge_route(route, methods, handler)
else:
route = Route(
handler=handler, methods=methods, pattern=pattern,
parameters=parameters)
self.routes_all[uri] = route
if properties['unhashable']:
self.routes_always_check.append(route)
elif parameters:
self.routes_dynamic[url_hash(uri)].append(route)
else:
self.routes_static[uri] = route
@staticmethod
def check_dynamic_route_exists(pattern, routes_to_check):
for ndx, route in enumerate(routes_to_check):
if route.pattern == pattern:
return ndx, route
else:
return -1, None
def remove(self, uri, clean_cache=True, host=None):
if host is not None:
uri = host + uri
try:
route = self.routes_all.pop(uri)
except KeyError:
raise RouteDoesNotExist("Route was not registered: {}".format(uri))
if route in self.routes_always_check:
self.routes_always_check.remove(route)
elif url_hash(uri) in self.routes_dynamic \
and route in self.routes_dynamic[url_hash(uri)]:
self.routes_dynamic[url_hash(uri)].remove(route)
else:
self.routes_static.pop(uri)
if clean_cache:
self._get.cache_clear()
def get(self, request):
"""
Gets a request handler based on the URL of the request, or raises an
error
:param request: Request object
:return: handler, arguments, keyword arguments
"""
if self.hosts is None:
return self._get(request.url, request.method, '')
else:
return self._get(request.url, request.method,
request.headers.get("Host", ''))
@lru_cache(maxsize=Config.ROUTER_CACHE_SIZE)
def _get(self, url, method, host):
"""
Gets a request handler based on the URL of the request, or raises an
error. Internal method for caching.
:param url: Request URL
:param method: Request method
:return: handler, arguments, keyword arguments
"""
url = host + url
# Check against known static routes
route = self.routes_static.get(url)
method_not_supported = InvalidUsage(
'Method {} not allowed for URL {}'.format(
method, url), status_code=405)
if route:
if route.methods and method not in route.methods:
raise method_not_supported
match = route.pattern.match(url)
else:
route_found = False
# Move on to testing all regex routes
for route in self.routes_dynamic[url_hash(url)]:
match = route.pattern.match(url)
route_found |= match is not None
# Do early method checking
if match and method in route.methods:
break
else:
# Lastly, check against all regex routes that cannot be hashed
for route in self.routes_always_check:
match = route.pattern.match(url)
route_found |= match is not None
# Do early method checking
if match and method in route.methods:
break
else:
# Route was found but the methods didn't match
if route_found:
raise method_not_supported
raise NotFound('Requested URL {} not found'.format(url))
kwargs = {p.name: p.cast(value)
for value, p
in zip(match.groups(1), route.parameters)}
route_handler = route.handler
if hasattr(route_handler, 'handlers'):
route_handler = route_handler.handlers[method]
return route_handler, [], kwargs