login tests

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 +270,117 @@ 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. 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
+
+If the authentication function cannot validate the user provided credentials it
+must return ``None``.
+
+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>`_
+
+
+
 Cross-Origin Resource Sharing (CORS)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -305,8 +416,8 @@ 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 +453,8 @@ 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

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 hashlib import sha1
+from microdot import Microdot
+from microdot.auth import BasicAuth
+
+
+def create_hash(password):
+    return sha1(password).hexdigest()
+
+
+USERS = {
+    'susan': create_hash(b'hello'),
+    'david': create_hash(b'bye'),
+}
+app = Microdot()
+auth = BasicAuth()
+
+
+@auth.authenticate
+async def check_credentials(request, username, password):
+    if username in USERS and USERS[username] == create_hash(password.encode()):
+        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/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 +1,122 @@
+from hashlib import sha1
+from microdot import Microdot, redirect
+from microdot.session import Session
+from microdot.login import Login
+
+
+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):
+        # note: to keep this example simple, passwords are hashed with the SHA1
+        # algorithm. In a real application, you should use a stronger
+        # algorithm, such as bcrypt.
+        return sha1(password.encode()).hexdigest()
+
+    def check_password(self, password):
+        return self.create_hash(password) == self.password_hash
+
+
+USERS = {
+    'user001': User('user001', 'susan', 'hello'),
+    'user002': User('user002', 'david', 'bye'),
+}
+
+app = Microdot()
+Session(app, secret_key='top-secret!')
+auth = Login()
+
+
+@auth.id_to_user
+async def get_user(user_id):
+    print('get_user', user_id)
+    return USERS.get(user_id)
+
+
+@app.route('/login', methods=['GET', 'POST'])
+async def login(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 auth.login_user(request, user,
+                                             remember=remember_me)
+    return redirect('/login')
+
+
+@app.route('/')
+@auth
+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')
+@auth.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')
+@auth
+async def logout(request):
+    await auth.logout_user(request)
+    return redirect('/')
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

examples/sessions/login.py

@@ -1,3 +1,7 @@
+# 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
 

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 +1,150 @@
+from time import time
+from microdot import redirect
+from microdot.microdot import urlencode, invoke_handler
+
+
+class Login:
+    def __init__(self, login_url='/login'):
+        self.login_url = login_url
+        self.user_callback = None
+        self.user_id_callback = lambda user: user.id
+
+    def id_to_user(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_callback = f
+
+    def user_to_id(self, f):
+        """Decorator to configure the user ID callback.
+
+        The decorated functon receives the user object as an argument and must
+        return the corresponding user ID. By default, the ``id`` attribute of
+        the user object is used.
+        """
+        self.user_id_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'] = await invoke_handler(self.user_id_callback, user)
+        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.
+        """
+        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_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, as opposite to a session
+        that was restored from a "remember me" cookie.
+        """
+        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

tests/__init__.py

@@ -9,3 +9,4 @@ 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

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 +1,185 @@
+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.id_to_user
+        def id_to_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):
+        app = Microdot()
+        Session(app, secret_key='secret')
+        login = Login()
+
+        @login.id_to_user
+        def id_to_user(user_id):
+            return None
+
+        @login.user_to_id
+        def user_to_id(user):
+            return user
+
+        @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')
+
+        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):
+        app = Microdot()
+        Session(app, secret_key='secret')
+        login = Login()
+
+        @login.id_to_user
+        def id_to_user(user_id):
+            return user_id
+
+        @login.user_to_id
+        def user_to_id(user):
+            return user
+
+        @app.get('/')
+        @login
+        async def index(request):
+            return 'ok'
+
+        @app.post('/login')
+        async def login_route(request):
+            return await login.login_user(request, '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):
+        app = Microdot()
+        Session(app, secret_key='secret')
+        login = Login()
+
+        @login.id_to_user
+        def id_to_user(user_id):
+            return user_id
+
+        @login.user_to_id
+        def user_to_id(user):
+            return user
+
+        @app.get('/')
+        @login
+        def index(request):
+            return request.g.current_user
+
+        @app.post('/login')
+        async def login_route(request):
+            return await login.login_user(request, 'user', 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}'
+
+        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')
+        res = self._run(client.get('/fresh'))
+        self.assertEqual(res.status_code, 200)
+        self.assertEqual(res.text, 'fresh user')
+
+        del client.cookies['session']
+        print(client.cookies)
+        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_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'