app = Flask(__name__)
 
@app.route("/hello/<username>")
def hello_user(username):
  return "Hello {}!".format(username)

 
import re
 
route_regex = re.compile(r"^/hello/(.+)$")
match = route_regex.match("/hello/ains")
 
print match.groups()

/hello/(<?P<username>.+)"

route_regex = re.compile(r'^/hello/(?P<username>.+)$')
match = route_regex.match("/hello/ains")
 
print match.groupdict()

 
def build_route_pattern(route):
  route_regex = re.sub(r'(<w+>)', r'(?P1.+)', route)
  return re.compile("^{}$".format(route_regex))
 
print build_route_pattern('/hello/<username>')

/hello/<username>

^/hello/(?P<username>.+)$

class NotFlask():
  def __init__(self):
    self.routes = {}
 
  def route(self, route_str):
    def decorator(f):
      self.routes[route_str] = f
      return f
 
    return decorator
 
  def serve(self, path):
    view_function = self.routes.get(path)
    if view_function:
      return view_function()
    else:
      raise ValueError('Route "{}"" has not been registered'.format(path))
 
app = NotFlask()
 
@app.route("/")
def hello():
  return "Hello World!"

 
class NotFlask():
  def __init__(self):
    self.routes = []
 
  # Here's our build_route_pattern we made earlier
  @staticmethod
  def build_route_pattern(route):
    route_regex = re.sub(r'(<w+>)', r'(?P1.+)', route)
    return re.compile("^{}$".format(route_regex))
 
  def route(self, route_str):
    def decorator(f):
      # Instead of inserting into a dictionary,
      # We'll append the tuple to our route list
      route_pattern = self.build_route_pattern(route_str)
      self.routes.append((route_pattern, f))
 
      return f
 
    return decorator

 
def get_route_match(path):
  for route_pattern, view_function in self.routes:
    m = route_pattern.match(path)
    if m:
      return m.groupdict(), view_function
 
  return None

 
def hello_user(username):
  return "Hello {}!".format(username)

>>> hello_user("ains")
Hello ains!

>>> hello_user(username="ains")
Hello ains!

>>> kwargs = {"username": "ains"}
>>> hello_user(**kwargs)
Hello ains!

class NotFlask():
  def __init__(self):
    self.routes = []
 
  @staticmethod
  def build_route_pattern(route):
    route_regex = re.sub(r'(<w+>)', r'(?P1.+)', route)
    return re.compile("^{}$".format(route_regex))
 
  def route(self, route_str):
    def decorator(f):
      route_pattern = self.build_route_pattern(route_str)
      self.routes.append((route_pattern, f))
 
      return f
 
    return decorator
 
  def get_route_match(self, path):
    for route_pattern, view_function in self.routes:
      m = route_pattern.match(path)
      if m:
        return m.groupdict(), view_function
 
    return None
 
  def serve(self, path):
    route_match = self.get_route_match(path)
    if route_match:
      kwargs, view_function = route_match
      return view_function(**kwargs)
    else:
      raise ValueError('Route "{}"" has not been registered'.format(path))

 
app = NotFlask()
 
@app.route("/hello/")
def hello_user(username):
return "Hello {}!".format(username)
 
print app.serve("/hello/ains")