from .abstract import AbstractRouter
from .exceptions import RouteNotRegisteredException
from .http import HTTP, Stream, Request, Response
[docs]class Router(AbstractRouter):
"""User should never construct Router"""
# todo: I may want to change the constructor
def __init__(self, default_get):
"""
:param default_get: should be a handler function
"""
self._routes = {
'GET': {},
'POST': {}
}
self.default_get = default_get
[docs] def register(self, method: str, route: str, handler):
assert method in ['GET', 'POST'] # 这只是目前为了测试而加的限制
self._routes[method][route] = handler
[docs] def find_match(self, path: str):
"""
'user/{userId}' should match 'user/abc'
userId = abc
return a tuple (matched, parameters)
matched is the route which matches the incoming path
parameters is a dict of parameters and their values
"""
# todo: now the problem is how to implement it
# todo: pattern matching should be independent from :method,
# todo: but the current implementation doesn't support it. Should improve it later.
for routes_of_this_method in self._routes.values():
for route in routes_of_this_method:
matched, parameters = self._match(route, path)
# this function returns the first match, not the best match
if matched:
return route, parameters
# did not find any route which matches the path
return None, None
@classmethod
def _match(cls, route, path):
# '/something/xxx/' to 'something/xxx'. Get rid of '/' at the left and the right end of a string
route = route.lstrip('/').rstrip('/').split('/')
path = path.lstrip('/').rstrip('/').split('/')
if len(route) != len(path):
return False, None
else:
# todo: optimize the logic
parameters = {}
for r, p in zip(route, path):
if r == p == '':
return True, None
if r == '' and r != p:
return False, None
if r[0] == '{' and r[-1] == '}':
parameters[r[1:-1]] = p
elif r != p:
return False, None
return True, parameters
# async
[docs] async def handle_route(self, http: HTTP, stream: Stream):
path = stream.headers[':path']
method = stream.headers[':method']
route, parameters = self.find_match(path)
# 如果没有任何匹配，就默认为静态文件读取
if route is None:
if method == 'GET':
handler = self.default_get
else:
handler = None
else:
handler = self._routes[method].get(route, None)
if handler is not None:
req = Request(stream, parameters)
res = Response(stream.stream_id, http)
await handler(req, res)
else:
raise RouteNotRegisteredException(path + ' is not a registered route')