Release 2.1.0

CHANGES.md

@@ -1,5 +1,14 @@
 # Microdot change log
 
+**Release 2.1.0** - 2025-02-04
+
+- User login support ([commit](https://github.com/miguelgrinberg/microdot/commit/d807011ad006e53e70c4594d7eac04d03bb08681))
+- Basic and token authentication support ([commit](https://github.com/miguelgrinberg/microdot/commit/675c9787974da926af446974cd96ef224e0ee27f))
+- Added `local` argument to the `app.mount()` method, to define sub-application specific before and after request handlers ([commit](https://github.com/miguelgrinberg/microdot/commit/fd7931e1aec173c60f81dad18c1a102ed8f0e081))
+- Added `Request.url_prefix`, `Request.subapp` and local mounts ([commit](https://github.com/miguelgrinberg/microdot/commit/fd7931e1aec173c60f81dad18c1a102ed8f0e081))
+- Added a front end to the SSE example [#281](https://github.com/miguelgrinberg/microdot/issues/281) ([commit](https://github.com/miguelgrinberg/microdot/commit/d487a73c1ea5b3467e23907618b348ca52e0235c)) (thanks **Maxi**!)
+- Additional ``app.mount()`` unit tests ([commit](https://github.com/miguelgrinberg/microdot/commit/cd87abba30206ec6d3928e0aabacb2fccf7baf70))
+
 **Release 2.0.7** - 2024-11-10
 
 - Accept responses with just a status code [#263](https://github.com/miguelgrinberg/microdot/issues/263) ([commit #1](https://github.com/miguelgrinberg/microdot/commit/4eac013087f807cafa244b8a6b7b0ed4c82ff150) [commit #2](https://github.com/miguelgrinberg/microdot/commit/c46e4291061046f1be13f300dd08645b71c16635))

docs/api.rst

@@ -44,6 +44,22 @@ User Sessions
 .. automodule:: microdot.session
    :members:
 
+Authentication
+--------------
+
+.. automodule:: microdot.auth
+   :inherited-members:
+   :special-members: __call__
+   :members:
+
+User Logins
+-----------
+
+.. automodule:: microdot.login
+   :inherited-members:
+   :special-members: __call__
+   :members:
+
 Cross-Origin Resource Sharing (CORS)
 ------------------------------------
 

docs/extensions.rst

@@ -5,8 +5,8 @@ Microdot is a highly extensible web application framework. The extensions
 described in this section are maintained as part of the Microdot project in
 the same source code repository.
 
-WebSocket Support
-~~~~~~~~~~~~~~~~~
+WebSocket
+~~~~~~~~-
 
 .. list-table::
    :align: left
@@ -39,8 +39,8 @@ Example::
                 message = await ws.receive()
                 await ws.send(message)
 
-Server-Sent Events Support
-~~~~~~~~~~~~~~~~~~~~~~~~~~
+Server-Sent Events
+~~~~~~~~~~~~~~~~~~
 
 .. list-table::
    :align: left
@@ -78,8 +78,8 @@ Example::
    the SSE object. For bidirectional communication with the client, use the
    WebSocket extension.
 
-Rendering Templates
-~~~~~~~~~~~~~~~~~~~
+Templates
+~~~~~~~~~
 
 Many web applications use HTML templates for rendering content to clients.
 Microdot includes extensions to render templates with the
@@ -202,8 +202,8 @@ must be used.
 .. note::
     The Jinja extension is not compatible with MicroPython.
 
-Maintaining Secure User Sessions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Secure User Sessions
+~~~~~~~~~~~~~~~~~~~~
 
 .. list-table::
    :align: left
@@ -270,6 +270,178 @@ The :func:`save() <microdot.session.SessionDict.save>` and
 :func:`delete() <microdot.session.SessionDict.delete>` methods are used to update
 and destroy the user session respectively.
 
+Authentication
+~~~~~~~~~~~~~~
+
+.. list-table::
+   :align: left
+
+   * - Compatibility
+     - | CPython & MicroPython
+
+   * - Required Microdot source files
+     - | `auth.py <https://github.com/miguelgrinberg/microdot/tree/main/src/microdot/auth.py>`_
+
+   * - Required external dependencies
+     - | None
+
+   * - Examples
+     - | `basic_auth.py <https://github.com/miguelgrinberg/microdot/blob/main/examples/auth/basic_auth.py>`_
+       | `token_auth.py <https://github.com/miguelgrinberg/microdot/blob/main/examples/auth/token_auth.py>`_
+
+The authentication extension provides helper classes for two commonly used
+authentication patterns, described below.
+
+Basic Authentication
+^^^^^^^^^^^^^^^^^^^^
+
+`Basic Authentication <https://en.wikipedia.org/wiki/Basic_access_authentication>`_
+is a method of authentication that is part of the HTTP specification. It allows
+clients to authenticate to a server using a username and a password. Web
+browsers have native support for Basic Authentication and will automatically
+prompt the user for a username and a password when a protected resource is
+accessed.
+
+To use Basic Authentication, create an instance of the :class:`BasicAuth <microdot.auth.BasicAuth>`
+class::
+
+    from microdot.auth import BasicAuth
+
+    auth = BasicAuth(app)
+
+Next, create an authentication function. The function must accept a request
+object and a username and password pair provided by the user. If the
+credentials are valid, the function must return an object that represents the
+user. If the authentication function cannot validate the user provided
+credentials it must return ``None``. Decorate the function with
+``@auth.authenticate``::
+
+    @auth.authenticate
+    async def verify_user(request, username, password):
+        user = await load_user_from_database(username)
+        if user and user.verify_password(password):
+            return user
+
+To protect a route with authentication, add the ``auth`` instance as a
+decorator::
+
+    @app.route('/')
+    @auth
+    async def index(request):
+        return f'Hello, {request.g.current_user}!'
+
+While running an authenticated request, the user object returned by the
+authenticaction function is accessible as ``request.g.current_user``.
+
+Token Authentication
+^^^^^^^^^^^^^^^^^^^^
+
+To set up token authentication, create an instance of :class:`TokenAuth <microdot.auth.TokenAuth>`::
+
+    from microdot.auth import TokenAuth
+
+    auth = TokenAuth()
+
+Then add a function that verifies the token and returns the user it belongs to,
+or ``None`` if the token is invalid or expired::
+
+    @auth.authenticate
+    async def verify_token(request, token):
+        return load_user_from_token(token)
+
+As with Basic authentication, the ``auth`` instance is used as a decorator to
+protect your routes::
+
+    @app.route('/')
+    @auth
+    async def index(request):
+        return f'Hello, {request.g.current_user}!'
+        
+User Logins
+~~~~~~~~~~~
+
+.. list-table::
+   :align: left
+
+   * - Compatibility
+     - | CPython & MicroPython
+
+   * - Required Microdot source files
+     - | `login.py <https://github.com/miguelgrinberg/microdot/tree/main/src/microdot/auth.py>`_
+       | `session.py <https://github.com/miguelgrinberg/microdot/tree/main/src/microdot/session.py>`_
+   * - Required external dependencies
+     - | CPython: `PyJWT <https://pyjwt.readthedocs.io/>`_
+       | MicroPython: `jwt.py <https://github.com/micropython/micropython-lib/blob/master/python-ecosys/pyjwt/jwt.py>`_,
+                      `hmac.py <https://github.com/micropython/micropython-lib/blob/master/python-stdlib/hmac/hmac.py>`_
+   * - Examples
+     - | `login.py <https://github.com/miguelgrinberg/microdot/blob/main/examples/login/login.py>`_
+
+The login extension provides user login functionality. The logged in state of
+the user is stored in the user session cookie, and an optional "remember me"
+cookie can also be added to keep the user logged in across browser sessions.
+
+To use this extension, create instances of the
+:class:`Session <microdot.session.Session>` and :class:`Login <microdot.login.Login>`
+class::
+
+    Session(app, secret_key='top-secret!')
+    login = Login()
+
+The ``Login`` class accept an optional argument with the URL of the login page.
+The default for this URL is */login*.
+
+The application must represent users as objects with an ``id`` attribute. A
+function decorated with ``@login.user_loader`` is used to load a user object::
+
+    @login.user_loader
+    async def get_user(user_id):
+        return database.get_user(user_id)
+
+The application must implement the login form. At the point in which the user
+credentials have been received and verified, a call to the
+:func:`login_user() <microdot.login.Login.login_user>` function must be made to
+record the user in the user session::
+
+    @app.route('/login', methods=['GET', 'POST'])
+    async def login(request):
+        # ...
+        if user.check_password(password):
+            return await login.login_user(request, user, remember=remember_me)
+        return redirect('/login')
+
+The optional ``remember`` argument is used to add a remember me cookie that
+will log the user in automatically in future sessions. A value of ``True`` will
+keep the log in active for 30 days. Alternatively, an integer number of days
+can be passed in this argument.
+
+Any routes that require the user to be logged in must be decorated with
+:func:`@login <microdot.login.Login.__call__>`::
+
+    @app.route('/')
+    @login
+    async def index(request):
+        # ...
+
+Routes that are of a sensitive nature can be decorated with
+:func:`@login.fresh <microdot.login.Login.fresh>`
+instead. This decorator requires that the user has logged in during the current
+session, and will ask the user to logged in again if the session was
+authenticated through a remember me cookie::
+
+    @app.get('/fresh')
+    @login.fresh
+    async def fresh(request):
+        # ...
+
+To log out a user, the :func:`logout_user() <microdot.auth.Login.logout_user>`
+is used::
+
+    @app.post('/logout')
+    @login
+    async def logout(request):
+        await login.logout_user(request)
+        return redirect('/')
+
 Cross-Origin Resource Sharing (CORS)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -305,8 +477,8 @@ Example::
     cors = CORS(app, allowed_origins=['https://example.com'],
                 allow_credentials=True)
 
-Testing with the Test Client
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Test Client
+~~~~~~~~~~~
 
 .. list-table::
    :align: left
@@ -342,8 +514,8 @@ Example::
 See the documentation for the :class:`TestClient <microdot.test_client.TestClient>`
 class for more details.
 
-Deploying on a Production Web Server
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Production Deployments
+~~~~~~~~~~~~~~~~~~~~~~
 
 The ``Microdot`` class creates its own simple web server. This is enough for an
 application deployed with MicroPython, but when using CPython it may be useful

docs/intro.rst

@@ -445,7 +445,7 @@ Mounting a Sub-Application
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Small Microdot applications can be written as a single source file, but this
-is not the best option for applications that past a certain size. To make it
+is not the best option for applications that pass a certain size. To make it
 simpler to write large applications, Microdot supports the concept of
 sub-applications that can be "mounted" on a larger application, possibly with
 a common URL prefix applied to all of its routes. For developers familiar with
@@ -501,11 +501,25 @@ The resulting application will have the customer endpoints available at
 */customers/* and the order endpoints available at */orders/*.
 
 .. note::
-   Before-request, after-request and error handlers defined in the
-   sub-application are also copied over to the main application at mount time.
-   Once installed in the main application, these handlers will apply to the
-   whole application and not just the sub-application in which they were
-   created.
+   During the handling of a request, the
+   :attr:`Request.url_prefix <microdot.Microdot.url_prefix>` attribute is
+   set to the URL prefix under which the sub-application was mounted, or an
+   empty string if the endpoint did not come from a sub-application or the
+   sub-application was mounted without a URL prefix. It is possible to issue a
+   redirect that is relative to the sub-application as follows::
+
+      return redirect(request.url_prefix + '/relative-url')
+
+When mounting an application as shown above, before-request, after-request and
+error handlers defined in the sub-application are copied over to the main
+application at mount time. Once installed in the main application, these
+handlers will apply to the whole application and not just the sub-application
+in which they were created.
+
+The :func:`mount() <microdot.Microdot.mount>` method has a ``local`` argument
+that defaults to ``False``. When this argument is set to ``True``, the
+before-request, after-request and error handlers defined in the sub-application
+will only apply to the sub-application.
 
 Shutting Down the Server
 ^^^^^^^^^^^^^^^^^^^^^^^^

examples/auth/README.md

@@ -0,0 +1 @@
+This directory contains examples that demonstrate basic and token authentication.

examples/auth/basic_auth.py

@@ -0,0 +1,31 @@
+from microdot import Microdot
+from microdot.auth import BasicAuth
+from pbkdf2 import generate_password_hash, check_password_hash
+
+
+# this example provides an implementation of the generate_password_hash and
+# check_password_hash functions that can be used in MicroPython. On CPython
+# there are many other options for password hashisng so there is no need to use
+# this custom solution.
+USERS = {
+    'susan': generate_password_hash('hello'),
+    'david': generate_password_hash('bye'),
+}
+app = Microdot()
+auth = BasicAuth()
+
+
+@auth.authenticate
+async def check_credentials(request, username, password):
+    if username in USERS and check_password_hash(USERS[username], password):
+        return username
+
+
+@app.route('/')
+@auth
+async def index(request):
+    return f'Hello, {request.g.current_user}!'
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

examples/auth/pbkdf2.py

@@ -0,0 +1,47 @@
+import os
+import hashlib
+
+# PBKDF2 secure password hashing algorithm obtained from:
+# https://codeandlife.com/2023/01/06/how-to-calculate-pbkdf2-hmac-sha256-with-
+# python,-example-code/
+
+
+def sha256(b):
+    return hashlib.sha256(b).digest()
+
+
+def ljust(b, n, f):
+    return b + f * (n - len(b))
+
+
+def gethmac(key, content):
+    okeypad = bytes(v ^ 0x5c for v in ljust(key, 64, b'\0'))
+    ikeypad = bytes(v ^ 0x36 for v in ljust(key, 64, b'\0'))
+    return sha256(okeypad + sha256(ikeypad + content))
+
+
+def pbkdf2(pwd, salt, iterations=1000):
+    U = salt + b'\x00\x00\x00\x01'
+    T = bytes(64)
+    for _ in range(iterations):
+        U = gethmac(pwd, U)
+        T = bytes(a ^ b for a, b in zip(U, T))
+    return T
+
+
+# The number of iterations may need to be adjusted depending on the hardware.
+# Lower numbers make the password hashing algorithm faster but less secure, so
+# the largest number that can be tolerated should be used.
+def generate_password_hash(password, salt=None, iterations=100000):
+    salt = salt or os.urandom(16)
+    dk = pbkdf2(password.encode(), salt, iterations)
+    return f'pbkdf2-hmac-sha256:{salt.hex()}:{iterations}:{dk.hex()}'
+
+
+def check_password_hash(password_hash, password):
+    algorithm, salt, iterations, dk = password_hash.split(':')
+    iterations = int(iterations)
+    if algorithm != 'pbkdf2-hmac-sha256':
+        return False
+    return pbkdf2(password.encode(), salt=bytes.fromhex(salt),
+                  iterations=iterations) == bytes.fromhex(dk)

examples/auth/token_auth.py

@@ -0,0 +1,26 @@
+from microdot import Microdot
+from microdot.auth import TokenAuth
+
+app = Microdot()
+auth = TokenAuth()
+
+TOKENS = {
+    'susan-token': 'susan',
+    'david-token': 'david',
+}
+
+
+@auth.authenticate
+async def check_token(request, token):
+    if token in TOKENS:
+        return TOKENS[token]
+
+
+@app.route('/')
+@auth
+async def index(request):
+    return f'Hello, {request.g.current_user}!'
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

examples/login/README.md

@@ -0,0 +1 @@
+This directory contains examples that demonstrate user logins.

examples/login/login.py

@@ -0,0 +1,123 @@
+from microdot import Microdot, redirect
+from microdot.session import Session
+from microdot.login import Login
+from pbkdf2 import generate_password_hash, check_password_hash
+
+# this example provides an implementation of the generate_password_hash and
+# check_password_hash functions that can be used in MicroPython. On CPython
+# there are many other options for password hashisng so there is no need to use
+# this custom solution.
+
+
+class User:
+    def __init__(self, id, username, password):
+        self.id = id
+        self.username = username
+        self.password_hash = self.create_hash(password)
+
+    def create_hash(self, password):
+        return generate_password_hash(password)
+
+    def check_password(self, password):
+        return check_password_hash(self.password_hash, password)
+
+
+USERS = {
+    'user001': User('user001', 'susan', 'hello'),
+    'user002': User('user002', 'david', 'bye'),
+}
+
+app = Microdot()
+Session(app, secret_key='top-secret!')
+login = Login()
+
+
+@login.user_loader
+async def get_user(user_id):
+    return USERS.get(user_id)
+
+
+@app.route('/login', methods=['GET', 'POST'])
+async def login_page(request):
+    if request.method == 'GET':
+        return '''
+            <!doctype html>
+            <html>
+              <body>
+                <h1>Please Login</h1>
+                <form method="POST">
+                  <p>
+                    Username<br>
+                    <input name="username" autofocus>
+                  </p>
+                  <p>
+                    Password:<br>
+                    <input name="password" type="password">
+                    <br>
+                  </p>
+                  <p>
+                    <input name="remember_me" type="checkbox"> Remember me
+                    <br>
+                  </p>
+                  <p>
+                    <button type="submit">Login</button>
+                  </p>
+                </form>
+              </body>
+            </html>
+        ''', {'Content-Type': 'text/html'}
+    username = request.form['username']
+    password = request.form['password']
+    remember_me = bool(request.form.get('remember_me'))
+
+    for user in USERS.values():
+        if user.username == username:
+            if user.check_password(password):
+                return await login.login_user(request, user,
+                                              remember=remember_me)
+    return redirect('/login')
+
+
+@app.route('/')
+@login
+async def index(request):
+    return f'''
+        <!doctype html>
+        <html>
+          <body>
+            <h1>Hello, {request.g.current_user.username}!</h1>
+            <p>
+              <a href="/fresh">Click here</a> to access the fresh login page.
+            </p>
+            <form method="POST" action="/logout">
+              <button type="submit">Logout</button>
+            </form>
+          </body>
+        </html>
+    ''', {'Content-Type': 'text/html'}
+
+
+@app.get('/fresh')
+@login.fresh
+async def fresh(request):
+    return f'''
+        <!doctype html>
+        <html>
+          <body>
+            <h1>Hello, {request.g.current_user.username}!</h1>
+            <p>This page requires a fresh login session.</p>
+            <p><a href="/">Go back</a> to the main page.</p>
+          </body>
+        </html>
+    ''', {'Content-Type': 'text/html'}
+
+
+@app.post('/logout')
+@login
+async def logout(request):
+    await login.logout_user(request)
+    return redirect('/')
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

examples/login/pbkdf2.py

@@ -0,0 +1,47 @@
+import os
+import hashlib
+
+# PBKDF2 secure password hashing algorithm obtained from:
+# https://codeandlife.com/2023/01/06/how-to-calculate-pbkdf2-hmac-sha256-with-
+# python,-example-code/
+
+
+def sha256(b):
+    return hashlib.sha256(b).digest()
+
+
+def ljust(b, n, f):
+    return b + f * (n - len(b))
+
+
+def gethmac(key, content):
+    okeypad = bytes(v ^ 0x5c for v in ljust(key, 64, b'\0'))
+    ikeypad = bytes(v ^ 0x36 for v in ljust(key, 64, b'\0'))
+    return sha256(okeypad + sha256(ikeypad + content))
+
+
+def pbkdf2(pwd, salt, iterations=1000):
+    U = salt + b'\x00\x00\x00\x01'
+    T = bytes(64)
+    for _ in range(iterations):
+        U = gethmac(pwd, U)
+        T = bytes(a ^ b for a, b in zip(U, T))
+    return T
+
+
+# The number of iterations may need to be adjusted depending on the hardware.
+# Lower numbers make the password hashing algorithm faster but less secure, so
+# the largest number that can be tolerated should be used.
+def generate_password_hash(password, salt=None, iterations=100000):
+    salt = salt or os.urandom(16)
+    dk = pbkdf2(password.encode(), salt, iterations)
+    return f'pbkdf2-hmac-sha256:{salt.hex()}:{iterations}:{dk.hex()}'
+
+
+def check_password_hash(password_hash, password):
+    algorithm, salt, iterations, dk = password_hash.split(':')
+    iterations = int(iterations)
+    if algorithm != 'pbkdf2-hmac-sha256':
+        return False
+    return pbkdf2(password.encode(), salt=bytes.fromhex(salt),
+                  iterations=iterations) == bytes.fromhex(dk)

examples/sessions/login.py

@@ -1,3 +1,6 @@
+# This is a simple example that demonstrates how to use the user session, but
+# is not intended as a complete login solution. See the login subdirectory for
+# a more complete example.
 from microdot import Microdot, Response, redirect
 from microdot.session import Session, with_session
 

examples/sse/counter.py

@@ -1,16 +1,28 @@
 import asyncio
-from microdot import Microdot
+from microdot import Microdot, send_file
 from microdot.sse import with_sse
 
 app = Microdot()
 
 
+@app.route("/")
+async def main(request):
+    return send_file('index.html')
+
+
 @app.route('/events')
 @with_sse
 async def events(request, sse):
-    for i in range(10):
-        await asyncio.sleep(1)
-        await sse.send({'counter': i})
+    print('Client connected')
+    try:
+        i = 0
+        while True:
+            await asyncio.sleep(1)
+            i += 1
+            await sse.send({'counter': i})
+    except asyncio.CancelledError:
+        pass
+    print('Client disconnected')
 
 
-app.run(debug=True)
+app.run()

examples/sse/index.html

@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Microdot SSE Example</title>
+    <meta charset="UTF-8">
+  </head>
+  <body>
+    <h1>Microdot SSE Example</h1>
+    <div id="log"></div>
+    <script>
+      const log = (text, color) => {
+        document.getElementById('log').innerHTML += `<span style="color: ${color}">${text}</span><br>`;
+      };
+
+      const eventSource = new EventSource('/events');
+
+      eventSource.onopen = () => {
+        log('Connection to server opened.', 'black');
+      };
+
+      eventSource.onmessage = (event) => {
+        log(`Received message: ${event.data}`, 'blue');
+      };
+
+      eventSource.onerror = (event) => {
+        log(`EventSource failed: ${event.type}`, 'red');
+      };
+    </script>
+  </body>
+</html>

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "microdot"
-version = "2.0.8.dev0"
+version = "2.1.0"
 authors = [
     { name = "Miguel Grinberg", email = "miguel.grinberg@gmail.com" },
 ]

src/microdot/auth.py

@@ -0,0 +1,144 @@
+from microdot import abort
+from microdot.microdot import invoke_handler
+
+
+class BaseAuth:
+    def __init__(self):
+        self.auth_callback = None
+        self.error_callback = None
+
+    def __call__(self, f):
+        """Decorator to protect a route with authentication.
+
+        An instance of this class must be used as a decorator on the routes
+        that need to be protected. Example::
+
+           auth = BasicAuth()  # or TokenAuth()
+
+           @app.route('/protected')
+           @auth
+           def protected(request):
+               # ...
+
+        Routes that are decorated in this way will only be invoked if the
+        authentication callback returned a valid user object, otherwise the
+        error callback will be executed.
+        """
+        async def wrapper(request, *args, **kwargs):
+            auth = self._get_auth(request)
+            if not auth:
+                return await invoke_handler(self.error_callback, request)
+            request.g.current_user = await invoke_handler(
+                self.auth_callback, request, *auth)
+            if not request.g.current_user:
+                return await invoke_handler(self.error_callback, request)
+            return await invoke_handler(f, request, *args, **kwargs)
+
+        return wrapper
+
+
+class BasicAuth(BaseAuth):
+    """Basic Authentication.
+
+    :param realm: The realm that is displayed when the user is prompted to
+                  authenticate in the browser.
+    :param charset: The charset that is used to encode the realm.
+    :param scheme: The authentication scheme. Defaults to 'Basic'.
+    :param error_status: The error status code to return when authentication
+                         fails. Defaults to 401.
+    """
+    def __init__(self, realm='Please login', charset='UTF-8', scheme='Basic',
+                 error_status=401):
+        super().__init__()
+        self.realm = realm
+        self.charset = charset
+        self.scheme = scheme
+        self.error_status = error_status
+        self.error_callback = self.authentication_error
+
+    def _get_auth(self, request):
+        auth = request.headers.get('Authorization')
+        if auth and auth.startswith('Basic '):
+            import binascii
+            try:
+                username, password = binascii.a2b_base64(
+                    auth[6:]).decode().split(':', 1)
+            except Exception:  # pragma: no cover
+                return None
+            return username, password
+
+    def authentication_error(self, request):
+        return '', self.error_status, {
+            'WWW-Authenticate': '{} realm="{}", charset="{}"'.format(
+                self.scheme, self.realm, self.charset)}
+
+    def authenticate(self, f):
+        """Decorator to configure the authentication callback.
+
+        This decorator must be used with a function that accepts the request
+        object, a username and a password and returns a user object if the
+        credentials are valid, or ``None`` if they are not. Example::
+
+           @auth.authenticate
+           async def check_credentials(request, username, password):
+               user = get_user(username)
+               if user and user.check_password(password):
+                   return get_user(username)
+        """
+        self.auth_callback = f
+
+
+class TokenAuth(BaseAuth):
+    """Token based authentication.
+
+    :param header: The name of the header that will contain the token. Defaults
+                   to 'Authorization'.
+    :param scheme: The authentication scheme. Defaults to 'Bearer'.
+    :param error_status: The error status code to return when authentication
+                         fails. Defaults to 401.
+    """
+    def __init__(self, header='Authorization', scheme='Bearer',
+                 error_status=401):
+        super().__init__()
+        self.header = header
+        self.scheme = scheme.lower()
+        self.error_status = error_status
+        self.error_callback = self.authentication_error
+
+    def _get_auth(self, request):
+        auth = request.headers.get(self.header)
+        if auth:
+            if self.header == 'Authorization':
+                try:
+                    scheme, token = auth.split(' ', 1)
+                except Exception:
+                    return None
+                if scheme.lower() == self.scheme:
+                    return (token.strip(),)
+            else:
+                return (auth,)
+
+    def authenticate(self, f):
+        """Decorator to configure the authentication callback.
+
+        This decorator must be used with a function that accepts the request
+        object, a username and a password and returns a user object if the
+        credentials are valid, or ``None`` if they are not. Example::
+
+           @auth.authenticate
+           async def check_credentials(request, token):
+               return get_user(token)
+        """
+        self.auth_callback = f
+
+    def errorhandler(self, f):
+        """Decorator to configure the error callback.
+
+        Microdot calls the error callback to allow the application to generate
+        a custom error response. The default error response is to call
+        ``abort(401)``.
+        """
+        self.error_callback = f
+
+    def authentication_error(self, request):
+        abort(self.error_status)

src/microdot/login.py

@@ -0,0 +1,163 @@
+from time import time
+from microdot import redirect
+from microdot.microdot import urlencode, invoke_handler
+
+
+class Login:
+    """User login support for Microdot.
+
+    :param login_url: the URL to redirect to when a login is required. The
+                      default is '/login'.
+    """
+    def __init__(self, login_url='/login'):
+        self.login_url = login_url
+        self.user_loader_callback = None
+
+    def user_loader(self, f):
+        """Decorator to configure the user callback.
+
+        The decorated function receives the user ID as an argument and must
+        return the corresponding user object, or ``None`` if the user ID is
+        invalid.
+        """
+        self.user_loader_callback = f
+
+    def _get_session(self, request):
+        return request.app._session.get(request)
+
+    def _update_remember_cookie(self, request, days, user_id=None):
+        remember_payload = request.app._session.encode({
+            'user_id': user_id,
+            'days': days,
+            'exp': time() + days * 24 * 60 * 60
+        })
+
+        @request.after_request
+        async def _set_remember_cookie(request, response):
+            response.set_cookie('_remember', remember_payload,
+                                max_age=days * 24 * 60 * 60)
+            return response
+
+    def _get_user_id_from_session(self, request):
+        session = self._get_session(request)
+        if session and '_user_id' in session:
+            return session['_user_id']
+        if '_remember' in request.cookies:
+            remember_payload = request.app._session.decode(
+                request.cookies['_remember'])
+            user_id = remember_payload.get('user_id')
+            if user_id:  # pragma: no branch
+                self._update_remember_cookie(
+                    request, remember_payload.get('_days', 30), user_id)
+                session['_user_id'] = user_id
+                session['_fresh'] = False
+                session.save()
+                return user_id
+
+    async def _redirect_to_login(self, request):
+        return '', 302, {'Location': self.login_url + '?next=' + urlencode(
+            request.url)}
+
+    async def login_user(self, request, user, remember=False,
+                         redirect_url='/'):
+        """Log a user in.
+
+        :param request: the request object
+        :param user: the user object
+        :param remember: if the user's logged in state should be remembered
+                         with a cookie after the session ends. Set to the
+                         number of days the remember cookie should last, or to
+                         ``True`` to use a default duration of 30 days.
+        :param redirect_url: the URL to redirect to after login
+
+        This call marks the user as logged in by storing their user ID in the
+        user session. The application must call this method to log a user in
+        after their credentials have been validated.
+
+        The method returns a redirect response, either to the URL the user
+        originally intended to visit, or if there is no original URL to the URL
+        specified by the `redirect_url`.
+        """
+        session = self._get_session(request)
+        session['_user_id'] = user.id
+        session['_fresh'] = True
+        session.save()
+
+        if remember:
+            days = 30 if remember is True else int(remember)
+            self._update_remember_cookie(request, days, session['_user_id'])
+
+        next_url = request.args.get('next', redirect_url)
+        if not next_url.startswith('/'):
+            next_url = redirect_url
+        return redirect(next_url)
+
+    async def logout_user(self, request):
+        """Log a user out.
+
+        :param request: the request object
+
+        This call removes information about the user's log in from the user
+        session. If a remember cookie exists, it is removed as well.
+        """
+        session = self._get_session(request)
+        session.pop('_user_id', None)
+        session.pop('_fresh', None)
+        session.save()
+        if '_remember' in request.cookies:
+            self._update_remember_cookie(request, 0)
+
+    def __call__(self, f):
+        """Decorator to protect a route with authentication.
+
+        If the user is not logged in, Microdot will redirect to the login page
+        first. The decorated route will only run after successful login by the
+        user. If the user is already logged in, the route will run immediately.
+        Example::
+
+            login = Login()
+
+            @app.route('/secret')
+            @login
+            async def secret(request):
+                # only accessible to authenticated users
+
+        """
+        async def wrapper(request, *args, **kwargs):
+            user_id = self._get_user_id_from_session(request)
+            if not user_id:
+                return await self._redirect_to_login(request)
+            request.g.current_user = await invoke_handler(
+                self.user_loader_callback, user_id)
+            if not request.g.current_user:
+                return await self._redirect_to_login(request)
+            return await invoke_handler(f, request, *args, **kwargs)
+
+        return wrapper
+
+    def fresh(self, f):
+        """Decorator to protect a route with "fresh" authentication.
+
+        This decorator prevents the route from running when the login session
+        is not fresh. A fresh session is a session that has been created from
+        direct user interaction with the login page, while a non-fresh session
+        occurs when a login is restored from a "remember me" cookie. Example::
+
+            login = Login()
+
+            @app.route('/secret')
+            @auth.fresh
+            async def secret(request):
+                # only accessible to authenticated users
+                # users logged in via remember me cookie will need to
+                # re-authenticate
+        """
+        base_wrapper = self.__call__(f)
+
+        async def wrapper(request, *args, **kwargs):
+            session = self._get_session(request)
+            if session.get('_fresh'):
+                return await base_wrapper(request, *args, **kwargs)
+            return await self._redirect_to_login(request)
+
+        return wrapper

src/microdot/microdot.py

@@ -329,7 +329,8 @@ class Request:
         pass
 
     def __init__(self, app, client_addr, method, url, http_version, headers,
-                 body=None, stream=None, sock=None):
+                 body=None, stream=None, sock=None, url_prefix='',
+                 subapp=None):
         #: The application instance to which this request belongs.
         self.app = app
         #: The address of the client, as a tuple (host, port).
@@ -338,6 +339,12 @@ class Request:
         self.method = method
         #: The request URL, including the path and query string.
         self.url = url
+        #: The URL prefix, if the endpoint comes from a mounted
+        #: sub-application, or else ''.
+        self.url_prefix = url_prefix
+        #: The sub-application instance, or `None` if this isn't a mounted
+        #: endpoint.
+        self.subapp = subapp
         #: The path portion of the URL.
         self.path = url
         #: The query string portion of the URL.
@@ -891,6 +898,9 @@ class URLPattern():
         except ValueError:
             return None, None
 
+    def __repr__(self):  # pragma: no cover
+        return 'URLPattern: {}'.format(self.url_pattern)
+
 
 class HTTPException(Exception):
     def __init__(self, status_code, reason=None):
@@ -959,7 +969,7 @@ class Microdot:
         def decorated(f):
             self.url_map.append(
                 ([m.upper() for m in (methods or ['GET'])],
-                 URLPattern(url_pattern), f))
+                 URLPattern(url_pattern), f, '', None))
             return f
         return decorated
 
@@ -1127,24 +1137,33 @@ class Microdot:
             return f
         return decorated
 
-    def mount(self, subapp, url_prefix=''):
+    def mount(self, subapp, url_prefix='', local=False):
         """Mount a sub-application, optionally under the given URL prefix.
 
         :param subapp: The sub-application to mount.
         :param url_prefix: The URL prefix to mount the application under.
+        :param local: When set to ``True``, the before, after and error request
+                      handlers only apply to endpoints defined in the
+                      sub-application. When ``False``, they apply to the entire
+                      application. The default is ``False``.
         """
-        for methods, pattern, handler in subapp.url_map:
+        for methods, pattern, handler, _prefix, _subapp in subapp.url_map:
             self.url_map.append(
                 (methods, URLPattern(url_prefix + pattern.url_pattern),
-                 handler))
-        for handler in subapp.before_request_handlers:
-            self.before_request_handlers.append(handler)
-        for handler in subapp.after_request_handlers:
-            self.after_request_handlers.append(handler)
-        for handler in subapp.after_error_request_handlers:
-            self.after_error_request_handlers.append(handler)
-        for status_code, handler in subapp.error_handlers.items():
-            self.error_handlers[status_code] = handler
+                 handler, url_prefix + _prefix, _subapp or subapp))
+        if not local:
+            for handler in subapp.before_request_handlers:
+                self.before_request_handlers.append(handler)
+            subapp.before_request_handlers = []
+            for handler in subapp.after_request_handlers:
+                self.after_request_handlers.append(handler)
+            subapp.after_request_handlers = []
+            for handler in subapp.after_error_request_handlers:
+                self.after_error_request_handlers.append(handler)
+            subapp.after_error_request_handlers = []
+            for status_code, handler in subapp.error_handlers.items():
+                self.error_handlers[status_code] = handler
+            subapp.error_handlers = {}
 
     @staticmethod
     def abort(status_code, reason=None):
@@ -1302,23 +1321,28 @@ class Microdot:
     def find_route(self, req):
         method = req.method.upper()
         if method == 'OPTIONS' and self.options_handler:
-            return self.options_handler(req)
+            return self.options_handler(req), '', None
         if method == 'HEAD':
             method = 'GET'
         f = 404
-        for route_methods, route_pattern, route_handler in self.url_map:
+        p = ''
+        s = None
+        for route_methods, route_pattern, route_handler, url_prefix, subapp \
+                in self.url_map:
             req.url_args = route_pattern.match(req.path)
             if req.url_args is not None:
+                p = url_prefix
+                s = subapp
                 if method in route_methods:
                     f = route_handler
                     break
                 else:
                     f = 405
-        return f
+        return f, p, s
 
     def default_options_handler(self, req):
         allow = []
-        for route_methods, route_pattern, route_handler in self.url_map:
+        for route_methods, route_pattern, _, _, _ in self.url_map:
             if route_pattern.match(req.path) is not None:
                 allow.extend(route_methods)
         if 'GET' in allow:
@@ -1349,43 +1373,76 @@ class Microdot:
                 method=req.method, path=req.path,
                 status_code=res.status_code))
 
+    def get_request_handlers(self, req, attr, local_first=True):
+        handlers = getattr(self, attr + '_handlers')
+        local_handlers = getattr(req.subapp, attr + '_handlers') \
+            if req and req.subapp else []
+        return local_handlers + handlers if local_first \
+            else handlers + local_handlers
+
+    async def error_response(self, req, status_code, reason=None):
+        if req and req.subapp and status_code in req.subapp.error_handlers:
+            return await invoke_handler(
+                req.subapp.error_handlers[status_code], req)
+        elif status_code in self.error_handlers:
+            return await invoke_handler(self.error_handlers[status_code], req)
+        return reason or 'N/A', status_code
+
     async def dispatch_request(self, req):
         after_request_handled = False
         if req:
             if req.content_length > req.max_content_length:
-                if 413 in self.error_handlers:
-                    res = await invoke_handler(self.error_handlers[413], req)
-                else:
-                    res = 'Payload too large', 413
+                # the request body is larger than allowed
+                res = await self.error_response(req, 413, 'Payload too large')
             else:
-                f = self.find_route(req)
+                # find the route in the app's URL map
+                f, req.url_prefix, req.subapp = self.find_route(req)
+
                 try:
                     res = None
                     if callable(f):
-                        for handler in self.before_request_handlers:
+                        # invoke the before request handlers
+                        for handler in self.get_request_handlers(
+                                req, 'before_request', False):
                             res = await invoke_handler(handler, req)
                             if res:
                                 break
+
+                        # invoke the endpoint handler
                         if res is None:
-                            res = await invoke_handler(
-                                f, req, **req.url_args)
+                            res = await invoke_handler(f, req, **req.url_args)
+
+                        # process the response
                         if isinstance(res, int):
+                            # an integer response is taken as a status code
+                            # with an empty body
                             res = '', res
                         if isinstance(res, tuple):
+                            # handle a tuple response
                             if isinstance(res[0], int):
+                                # a tuple that starts with an int has an empty
+                                # body
                                 res = ('', res[0],
                                        res[1] if len(res) > 1 else {})
                             body = res[0]
                             if isinstance(res[1], int):
+                                # extract the status code and headers (if
+                                # available)
                                 status_code = res[1]
                                 headers = res[2] if len(res) > 2 else {}
                             else:
+                                # if the status code is missing, assume 200
                                 status_code = 200
                                 headers = res[1]
                             res = Response(body, status_code, headers)
                         elif not isinstance(res, Response):
+                            # any other response types are wrapped in a
+                            # Response object
                             res = Response(res)
-                        for handler in self.after_request_handlers:
+
+                        # invoke the after request handlers
+                        for handler in self.get_request_handlers(
+                                req, 'after_request', True):
                             res = await invoke_handler(
                                 handler, req, res) or res
                         for handler in req.after_request_handlers:
@@ -1393,50 +1450,62 @@ class Microdot:
                                 handler, req, res) or res
                         after_request_handled = True
                     elif isinstance(f, dict):
+                        # the response from an OPTIONS request is a dict with
+                        # headers
                         res = Response(headers=f)
-                    elif f in self.error_handlers:
-                        res = await invoke_handler(self.error_handlers[f], req)
                     else:
-                        res = 'Not found', f
+                        # if the route is not found, return a 404 or 405
+                        # response as appropriate
+                        res = await self.error_response(req, f, 'Not found')
                 except HTTPException as exc:
-                    if exc.status_code in self.error_handlers:
-                        res = self.error_handlers[exc.status_code](req)
-                    else:
-                        res = exc.reason, exc.status_code
+                    # an HTTP exception was raised while handling this request
+                    res = await self.error_response(req, exc.status_code,
+                                                    exc.reason)
                 except Exception as exc:
+                    # an unexpected exception was raised while handling this
+                    # request
                     print_exception(exc)
-                    exc_class = None
+
+                    # invoke the error handler for the exception class if one
+                    # exists
+                    handler = None
                     res = None
-                    if exc.__class__ in self.error_handlers:
-                        exc_class = exc.__class__
+                    if req.subapp and exc.__class__ in \
+                            req.subapp.error_handlers:
+                        handler = req.subapp.error_handlers[exc.__class__]
+                    elif exc.__class__ in self.error_handlers:
+                        handler = self.error_handlers[exc.__class__]
                     else:
+                        # walk up the exception class hierarchy to try to find
+                        # a handler
                         for c in mro(exc.__class__)[1:]:
-                            if c in self.error_handlers:
-                                exc_class = c
+                            if req.subapp and c in req.subapp.error_handlers:
+                                handler = req.subapp.error_handlers[c]
                                 break
-                    if exc_class:
+                            elif c in self.error_handlers:
+                                handler = self.error_handlers[c]
+                                break
+                    if handler:
                         try:
-                            res = await invoke_handler(
-                                self.error_handlers[exc_class], req, exc)
+                            res = await invoke_handler(handler, req, exc)
                         except Exception as exc2:  # pragma: no cover
                             print_exception(exc2)
                     if res is None:
-                        if 500 in self.error_handlers:
-                            res = await invoke_handler(
-                                self.error_handlers[500], req)
-                        else:
-                            res = 'Internal server error', 500
+                        # if there is still no response, issue a 500 error
+                        res = await self.error_response(
+                            req, 500, 'Internal server error')
         else:
-            if 400 in self.error_handlers:
-                res = await invoke_handler(self.error_handlers[400], req)
-            else:
-                res = 'Bad request', 400
+            # if the request could not be parsed, issue a 400 error
+            res = await self.error_response(req, 400, 'Bad request')
         if isinstance(res, tuple):
             res = Response(*res)
         elif not isinstance(res, Response):
             res = Response(res)
         if not after_request_handled:
-            for handler in self.after_error_request_handlers:
+            # if the request did not finish due to an error, invoke the after
+            # error request handler
+            for handler in self.get_request_handlers(
+                    req, 'after_error_request', True):
                 res = await invoke_handler(
                     handler, req, res) or res
         res.is_head = (req and req.method == 'HEAD')

tests/__init__.py

@@ -9,3 +9,5 @@ from tests.test_sse import *  # noqa: F401, F403
 from tests.test_cors import *  # noqa: F401, F403
 from tests.test_utemplate import *  # noqa: F401, F403
 from tests.test_session import *  # noqa: F401, F403
+from tests.test_auth import *  # noqa: F401, F403
+from tests.test_login import *  # noqa: F401, F403

tests/test_auth.py

@@ -0,0 +1,125 @@
+import asyncio
+import binascii
+import unittest
+from microdot import Microdot
+from microdot.auth import BasicAuth, TokenAuth
+from microdot.test_client import TestClient
+
+
+class TestAuth(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        if hasattr(asyncio, 'set_event_loop'):
+            asyncio.set_event_loop(asyncio.new_event_loop())
+        cls.loop = asyncio.get_event_loop()
+
+    def _run(self, coro):
+        return self.loop.run_until_complete(coro)
+
+    def test_basic_auth(self):
+        app = Microdot()
+        basic_auth = BasicAuth()
+
+        @basic_auth.authenticate
+        def authenticate(request, username, password):
+            if username == 'foo' and password == 'bar':
+                return {'username': username}
+
+        @app.route('/')
+        @basic_auth
+        def index(request):
+            return request.g.current_user['username']
+
+        client = TestClient(app)
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={
+            'Authorization': 'Basic ' + binascii.b2a_base64(
+                b'foo:bar').decode()}))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'foo')
+
+        res = self._run(client.get('/', headers={
+            'Authorization': 'Basic ' + binascii.b2a_base64(
+                b'foo:baz').decode()}))
+        self.assertEqual(res.status_code, 401)
+
+    def test_token_auth(self):
+        app = Microdot()
+        token_auth = TokenAuth()
+
+        @token_auth.authenticate
+        def authenticate(request, token):
+            if token == 'foo':
+                return 'user'
+
+        @app.route('/')
+        @token_auth
+        def index(request):
+            return request.g.current_user
+
+        client = TestClient(app)
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={
+            'Authorization': 'Basic foo'}))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={'Authorization': 'foo'}))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={
+            'Authorization': 'Bearer foo'}))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'user')
+
+    def test_token_auth_custom_header(self):
+        app = Microdot()
+        token_auth = TokenAuth(header='X-Auth-Token')
+
+        @token_auth.authenticate
+        def authenticate(request, token):
+            if token == 'foo':
+                return 'user'
+
+        @app.route('/')
+        @token_auth
+        def index(request):
+            return request.g.current_user
+
+        client = TestClient(app)
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={
+            'Authorization': 'Basic foo'}))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={'Authorization': 'foo'}))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={
+            'Authorization': 'Bearer foo'}))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={
+            'X-Token-Auth': 'Bearer foo'}))
+        self.assertEqual(res.status_code, 401)
+
+        res = self._run(client.get('/', headers={'X-Auth-Token': 'foo'}))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'user')
+
+        res = self._run(client.get('/', headers={'x-auth-token': 'foo'}))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'user')
+
+        @token_auth.errorhandler
+        def error_handler(request):
+            return {'status_code': 403}, 403
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 403)
+        self.assertEqual(res.json, {'status_code': 403})

tests/test_login.py

@@ -0,0 +1,188 @@
+import asyncio
+import unittest
+from microdot import Microdot
+from microdot.login import Login
+from microdot.session import Session
+from microdot.test_client import TestClient
+
+
+class TestLogin(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        if hasattr(asyncio, 'set_event_loop'):
+            asyncio.set_event_loop(asyncio.new_event_loop())
+        cls.loop = asyncio.get_event_loop()
+
+    def _run(self, coro):
+        return self.loop.run_until_complete(coro)
+
+    def test_login(self):
+        app = Microdot()
+        Session(app, secret_key='secret')
+        login = Login()
+
+        class User:
+            def __init__(self, id, name):
+                self.id = id
+                self.name = name
+
+        @login.user_loader
+        def load_user(user_id):
+            return User(user_id, f'user{user_id}')
+
+        @app.get('/')
+        @login
+        def index(request):
+            return request.g.current_user.name
+
+        @app.post('/login')
+        async def login_route(request):
+            return await login.login_user(request, User(123, 'user123'))
+
+        @app.post('/logout')
+        async def logout_route(request):
+            await login.logout_user(request)
+            return 'ok'
+
+        client = TestClient(app)
+        res = self._run(client.get('/?foo=bar'))
+        self.assertEqual(res.status_code, 302)
+        self.assertEqual(res.headers['Location'], '/login?next=/%3Ffoo%3Dbar')
+
+        res = self._run(client.post('/login?next=/%3Ffoo=bar'))
+        self.assertEqual(res.status_code, 302)
+        self.assertEqual(res.headers['Location'], '/?foo=bar')
+        self.assertEqual(len(res.headers['Set-Cookie']), 1)
+        self.assertIn('session', client.cookies)
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'user123')
+
+        res = self._run(client.post('/logout'))
+        self.assertEqual(res.status_code, 200)
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 302)
+
+    def test_login_bad_user_id(self):
+        class User:
+            def __init__(self, id, name):
+                self.id = id
+                self.name = name
+
+        app = Microdot()
+        Session(app, secret_key='secret')
+        login = Login()
+
+        @login.user_loader
+        def load_user(user_id):
+            return None
+
+        @app.get('/foo')
+        @login
+        async def index(request):
+            return 'ok'
+
+        @app.post('/login')
+        async def login_route(request):
+            return await login.login_user(request, User(1, 'user'))
+
+        client = TestClient(app)
+        res = self._run(client.post('/login?next=/'))
+        self.assertEqual(res.status_code, 302)
+        self.assertEqual(res.headers['Location'], '/')
+        res = self._run(client.get('/foo'))
+        self.assertEqual(res.status_code, 302)
+        self.assertEqual(res.headers['Location'], '/login?next=/foo')
+
+    def test_login_bad_redirect(self):
+        class User:
+            def __init__(self, id, name):
+                self.id = id
+                self.name = name
+
+        app = Microdot()
+        Session(app, secret_key='secret')
+        login = Login()
+
+        @login.user_loader
+        def load_user(user_id):
+            return user_id
+
+        @app.get('/')
+        @login
+        async def index(request):
+            return 'ok'
+
+        @app.post('/login')
+        async def login_route(request):
+            return await login.login_user(request, User(1, 'user'))
+
+        client = TestClient(app)
+        res = self._run(client.post('/login?next=http://example.com'))
+        self.assertEqual(res.status_code, 302)
+        self.assertEqual(res.headers['Location'], '/')
+
+    def test_login_remember(self):
+        class User:
+            def __init__(self, id, name):
+                self.id = id
+                self.name = name
+
+        app = Microdot()
+        Session(app, secret_key='secret')
+        login = Login()
+
+        @login.user_loader
+        def load_user(user_id):
+            return User(user_id, f'user{user_id}')
+
+        @app.get('/')
+        @login
+        def index(request):
+            return {'user': request.g.current_user.id}
+
+        @app.post('/login')
+        async def login_route(request):
+            return await login.login_user(request, User(1, 'user1'),
+                                          remember=True)
+
+        @app.post('/logout')
+        async def logout(request):
+            await login.logout_user(request)
+            return 'ok'
+
+        @app.get('/fresh')
+        @login.fresh
+        async def fresh(request):
+            return f'fresh {request.g.current_user.id}'
+
+        client = TestClient(app)
+        res = self._run(client.post('/login?next=/%3Ffoo=bar'))
+        self.assertEqual(res.status_code, 302)
+        self.assertEqual(res.headers['Location'], '/?foo=bar')
+        self.assertEqual(len(res.headers['Set-Cookie']), 2)
+        self.assertIn('session', client.cookies)
+        self.assertIn('_remember', client.cookies)
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, '{"user": 1}')
+        res = self._run(client.get('/fresh'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'fresh 1')
+
+        del client.cookies['session']
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 200)
+        res = self._run(client.get('/fresh'))
+        self.assertEqual(res.status_code, 302)
+        self.assertEqual(res.headers['Location'], '/login?next=/fresh')
+
+        res = self._run(client.post('/logout'))
+        self.assertEqual(res.status_code, 200)
+        self.assertFalse('_remember' in client.cookies)
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 302)

tests/test_microdot.py

@@ -794,7 +794,7 @@ class TestMicrodot(unittest.TestCase):
 
         @subapp.route('/app')
         def index(req):
-            return req.g.before + ':foo'
+            return req.g.before + ':' + req.url_prefix
 
         app = Microdot()
         app.mount(subapp, url_prefix='/sub')
@@ -811,4 +811,203 @@ class TestMicrodot(unittest.TestCase):
         self.assertEqual(res.status_code, 200)
         self.assertEqual(res.headers['Content-Type'],
                          'text/plain; charset=UTF-8')
-        self.assertEqual(res.text, 'before:foo:after')
+        self.assertEqual(res.text, 'before:/sub:after')
+
+    def test_mount_local(self):
+        subapp1 = Microdot()
+        subapp2 = Microdot()
+
+        @subapp1.before_request
+        def before1(req):
+            req.g.before += ':before1'
+
+        @subapp1.after_error_request
+        def after_error1(req, res):
+            res.body += b':errorafter'
+
+        @subapp1.errorhandler(ValueError)
+        def value_error(req, exc):
+            return str(exc), 400
+
+        @subapp1.route('/')
+        def index1(req):
+            raise ZeroDivisionError()
+
+        @subapp1.route('/foo')
+        def foo(req):
+            return req.g.before + ':foo:' + req.url_prefix
+
+        @subapp1.route('/err')
+        def err(req):
+            raise ValueError('err')
+
+        @subapp1.route('/err2')
+        def err2(req):
+            class MyErr(ValueError):
+                pass
+
+            raise MyErr('err')
+
+        @subapp2.before_request
+        def before2(req):
+            req.g.before += ':before2'
+
+        @subapp2.after_request
+        def after2(req, res):
+            res.body += b':after'
+
+        @subapp2.errorhandler(405)
+        def method_not_found2(req):
+            return '405', 405
+
+        @subapp2.route('/bar')
+        def bar(req):
+            return req.g.before + ':bar:' + req.url_prefix
+
+        @subapp2.route('/baz')
+        def baz(req):
+            abort(405)
+
+        app = Microdot()
+
+        @app.before_request
+        def before(req):
+            req.g.before = 'before-app'
+
+        @app.after_request
+        def after(req, res):
+            res.body += b':after-app'
+
+        app.mount(subapp1, local=True)
+        app.mount(subapp2, url_prefix='/sub', local=True)
+
+        client = TestClient(app)
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 500)
+        self.assertEqual(res.text, 'Internal server error:errorafter')
+
+        res = self._run(client.get('/foo'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.headers['Content-Type'],
+                         'text/plain; charset=UTF-8')
+        self.assertEqual(res.text, 'before-app:before1:foo::after-app')
+
+        res = self._run(client.get('/err'))
+        self.assertEqual(res.status_code, 400)
+        self.assertEqual(res.text, 'err:errorafter')
+
+        res = self._run(client.get('/err2'))
+        self.assertEqual(res.status_code, 400)
+        self.assertEqual(res.text, 'err:errorafter')
+
+        res = self._run(client.get('/sub/bar'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.headers['Content-Type'],
+                         'text/plain; charset=UTF-8')
+        self.assertEqual(res.text,
+                         'before-app:before2:bar:/sub:after:after-app')
+
+        res = self._run(client.post('/sub/bar'))
+        self.assertEqual(res.status_code, 405)
+        self.assertEqual(res.text, '405')
+
+        res = self._run(client.get('/sub/baz'))
+        self.assertEqual(res.status_code, 405)
+        self.assertEqual(res.text, '405')
+
+    def test_many_mounts(self):
+        subsubapp = Microdot()
+
+        @subsubapp.before_request
+        def subsubapp_before(req):
+            req.g.before = 'subsubapp'
+
+        @subsubapp.route('/')
+        def subsubapp_index(req):
+            return f'{req.g.before}:{req.subapp == subsubapp}:{req.url_prefix}'
+
+        subapp = Microdot()
+
+        @subapp.before_request
+        def subapp_before(req):
+            req.g.before = 'subapp'
+
+        @subapp.route('/')
+        def subapp_index(req):
+            return f'{req.g.before}:{req.subapp == subapp}:{req.url_prefix}'
+
+        app = Microdot()
+
+        @app.before_request
+        def app_before(req):
+            req.g.before = 'app'
+
+        @app.route('/')
+        def app_index(req):
+            return f'{req.g.before}:{req.subapp is None}:{req.url_prefix}'
+
+        subapp.mount(subsubapp, url_prefix='/subsub')
+        app.mount(subapp, url_prefix='/sub')
+
+        client = TestClient(app)
+
+        res = self._run(client.get('/sub/subsub/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'subsubapp:True:/sub/subsub')
+
+        res = self._run(client.get('/sub/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'subsubapp:True:/sub')
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'subsubapp:True:')
+
+    def test_many_local_mounts(self):
+        subsubapp = Microdot()
+
+        @subsubapp.before_request
+        def subsubapp_before(req):
+            req.g.before = 'subsubapp'
+
+        @subsubapp.route('/')
+        def subsubapp_index(req):
+            return f'{req.g.before}:{req.subapp == subsubapp}:{req.url_prefix}'
+
+        subapp = Microdot()
+
+        @subapp.before_request
+        def subapp_before(req):
+            req.g.before = 'subapp'
+
+        @subapp.route('/')
+        def subapp_index(req):
+            return f'{req.g.before}:{req.subapp == subapp}:{req.url_prefix}'
+
+        app = Microdot()
+
+        @app.before_request
+        def app_before(req):
+            req.g.before = 'app'
+
+        @app.route('/')
+        def app_index(req):
+            return f'{req.g.before}:{req.subapp is None}:{req.url_prefix}'
+
+        subapp.mount(subsubapp, url_prefix='/subsub', local=True)
+        app.mount(subapp, url_prefix='/sub', local=True)
+
+        client = TestClient(app)
+
+        res = self._run(client.get('/sub/subsub/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'subsubapp:True:/sub/subsub')
+
+        res = self._run(client.get('/sub/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'subapp:True:/sub')
+
+        res = self._run(client.get('/'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'app:True:')

tests/test_session.py

@@ -37,7 +37,7 @@ class TestSession(unittest.TestCase):
 
         @app.post('/set')
         @with_session
-        async def save_session(req, session):
+        def save_session(req, session):
             session['name'] = 'joe'
             session.save()
             return 'OK'