Wrote code documentation for the pagelets of the current implementation, and for some of the jinja2 templates

matemat/db/facade.py

@@ -232,7 +232,7 @@ class MatematDatabase(object):
                 'tkhash': tkhash
             })
 
-    def change_user(self, user: User, agent: User, **kwargs)\
+    def change_user(self, user: User, agent: Optional[User], **kwargs)\
             -> None:
         """
         Commit changes to the user in the database.  If writing the requested changes succeeded, the values are updated
@@ -240,7 +240,7 @@ class MatematDatabase(object):
         the ID field in the provided user object.
 
         :param user: The user object to update and to identify the requested user by.
-        :param agent: The user that is performing the change.
+        :param agent: The user that is performing the change.  Must be present if the balance is changed.
         :param kwargs: The properties to change.
         :raises DatabaseConsistencyError: If the user represented by the object does not exist.
         """
@@ -257,6 +257,8 @@ class MatematDatabase(object):
                 raise DatabaseConsistencyError(f'User with ID {user.id} does not exist')
             oldbalance: int = row[0]
             if balance != oldbalance:
+                if agent is None:
+                    raise ValueError('agent must not be None for a balance change')
                 c.execute('''
                 INSERT INTO transactions (user_id, value, old_balance)
                   VALUES (:user_id, :value, :old_balance)

matemat/webserver/pagelets/admin.py

@@ -1,4 +1,3 @@
-
 from typing import Any, Dict, Union
 
 import os
@@ -18,71 +17,116 @@ def admin(method: str,
           headers: Dict[str, str],
           config: Dict[str, str]) \
         -> Union[str, bytes, PageletResponse]:
+    """
+    The admin panel, shows a user's own settings.  Additionally, for administrators, settings to modify other users and
+    products are shown.
+    """
+    # If no user is logged in, redirect to the login page
     if 'authentication_level' not in session_vars or 'authenticated_user' not in session_vars:
         return RedirectResponse('/login')
     authlevel: int = session_vars['authentication_level']
     uid: int = session_vars['authenticated_user']
+    # Show a 403 Forbidden error page if no user is logged in (0) or a user logged in via touchkey (1)
     if authlevel < 2:
         raise HttpException(403)
 
+    # Connect to the database
     with MatematDatabase(config['DatabaseFile']) as db:
+        # Fetch the authenticated user
         user = db.get_user(uid)
+        # If the POST request contains a "change" parameter, delegate the change handling to the function below
         if method == 'POST' and 'change' in args:
             handle_change(args, user, db, config)
+        # If the POST request contains an "adminchange" parameter, delegate the change handling to the function below
         elif method == 'POST' and 'adminchange' in args and user.is_admin:
             handle_admin_change(args, db, config)
 
+        # Fetch all existing users and products from the database
         users = db.list_users()
         products = db.list_products()
+        # Render the "Admin/Settings" page
         return TemplateResponse('admin.html',
                                 authuser=user, authlevel=authlevel, users=users, products=products,
                                 setupname=config['InstanceName'])
 
 
 def handle_change(args: RequestArguments, user: User, db: MatematDatabase, config: Dict[str, str]) -> None:
+    """
+    Write the changes requested by a user for its own account to the database.
+
+    :param args: The RequestArguments object passed to the pagelet.
+    :param user: The user to edit.
+    :param db: The database facade where changes are written to.
+    :param config: The dictionary of config file entries from the [Pagelets] section.
+    """
     try:
+        # Read the type of change requested by the user, then switch over it
         change = str(args.change)
 
+        # The user requested a modification of its general account information (username, email)
         if change == 'account':
+            # Username and email must be set in the request arguments
             if 'username' not in args or 'email' not in args:
                 return
             username = str(args.username)
             email = str(args.email)
+            # An empty e-mail field should be interpreted as NULL
             if len(email) == 0:
                 email = None
+            # Attempt to update username and e-mail
             try:
-                db.change_user(user, name=username, email=email)
+                db.change_user(user, agent=None, name=username, email=email)
             except DatabaseConsistencyError:
-                pass
+                return
 
+        # The user requested a password change
         elif change == 'password':
+            # The old password and 2x the new password must be present
             if 'oldpass' not in args or 'newpass' not in args or 'newpass2' not in args:
                 return
+            # Read the passwords from the request arguments
             oldpass = str(args.oldpass)
             newpass = str(args.newpass)
             newpass2 = str(args.newpass2)
+            # The two instances of the new password must match
             if newpass != newpass2:
                 raise ValueError('New passwords don\'t match')
+            # Write the new password to the database
             db.change_password(user, oldpass, newpass)
 
+        # The user requested a touchkey change
         elif change == 'touchkey':
+            # The touchkey must be present
             if 'touchkey' not in args:
                 return
+            # Read the touchkey from the request arguments
             touchkey = str(args.touchkey)
+            # An empty touchkey field should set the touchkey to NULL (disable touchkey login)
             if len(touchkey) == 0:
                 touchkey = None
+            # Write the new touchkey to the database
             db.change_touchkey(user, '', touchkey, verify_password=False)
 
+        # The user requested an avatar change
         elif change == 'avatar':
+            # The new avatar field must be present
             if 'avatar' not in args:
                 return
+            # Read the raw image data from the request
             avatar = bytes(args.avatar)
+            # Only process the image, if its size is more than zero.  Zero size means no new image was uploaded
+            if len(avatar) == 0:
+                return
+            # Detect the MIME type
             filemagic: magic.FileMagic = magic.detect_from_content(avatar)
+            # Currently, only image/png is supported, don't process any other formats
             if filemagic.mime_type != 'image/png':
                 # TODO: Optionally convert to png
                 return
+            # Create the absolute path of the upload directory
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/users/')
             os.makedirs(abspath, exist_ok=True)
+            # Write the image to the file
             with open(os.path.join(abspath, f'{user.id}.png'), 'wb') as f:
                 f.write(avatar)
 
@@ -91,46 +135,76 @@ def handle_change(args: RequestArguments, user: User, db: MatematDatabase, confi
 
 
 def handle_admin_change(args: RequestArguments, db: MatematDatabase, config: Dict[str, str]):
+    """
+    Write the changes requested by an admin for users of products.
+
+    :param args: The RequestArguments object passed to the pagelet.
+    :param db: The database facade where changes are written to.
+    :param config: The dictionary of config file entries from the [Pagelets] section.
+    """
     try:
+        # Read the type of change requested by the admin, then switch over it
         change = str(args.adminchange)
 
+        # The user requested to create a new user
         if change == 'newuser':
+            # Only create a new user if all required properties of the user are present in the request arguments
             if 'username' not in args or 'email' not in args or 'password' not in args:
                 return
+            # Read the properties from the request arguments
             username = str(args.username)
             email = str(args.email)
+            # An empty e-mail field should be interpreted as NULL
             if len(email) == 0:
                 email = None
             password = str(args.password)
             is_member = 'ismember' in args
             is_admin = 'isadmin' in args
+            # Create the user in the database
             db.create_user(username, password, email, member=is_member, admin=is_admin)
 
+        # The user requested to create a new product
         elif change == 'newproduct':
+            # Only create a new product if all required properties of the product are present in the request arguments
             if 'name' not in args or 'pricemember' not in args or 'pricenonmember' not in args:
                 return
+            # Read the properties from the request arguments
             name = str(args.name)
             price_member = int(str(args.pricemember))
             price_non_member = int(str(args.pricenonmember))
+            # Create the user in the database
             newproduct = db.create_product(name, price_member, price_non_member)
+            # If a new product image was uploaded, process it
             if 'image' in args:
+                # Read the raw image data from the request
                 image = bytes(args.image)
+                # Only process the image, if its size is more than zero.  Zero size means no new image was uploaded
+                if len(image) == 0:
+                    return
+                # Detect the MIME type
                 filemagic: magic.FileMagic = magic.detect_from_content(image)
+                # Currently, only image/png is supported, don't process any other formats
                 if filemagic.mime_type != 'image/png':
                     # TODO: Optionally convert to png
                     return
-                if len(image) > 0:
+                # Create the absolute path of the upload directory
                 abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/products/')
                 os.makedirs(abspath, exist_ok=True)
+                # Write the image to the file
                 with open(os.path.join(abspath, f'{newproduct.id}.png'), 'wb') as f:
                     f.write(image)
 
+        # The user requested to restock a product
         elif change == 'restock':
+            # Only restock a product if all required properties are present in the request arguments
             if 'productid' not in args or 'amount' not in args:
                 return
+            # Read the properties from the request arguments
             productid = int(str(args.productid))
             amount = int(str(args.amount))
+            # Fetch the product to restock from the database
             product = db.get_product(productid)
+            # Write the new stock count to the database
             db.restock(product, amount)
 
     except UnicodeDecodeError:

matemat/webserver/pagelets/buy.py

@@ -12,13 +12,22 @@ def buy(method: str,
         headers: Dict[str, str],
         config: Dict[str, str]) \
         -> Union[str, bytes, PageletResponse]:
+    """
+    The purchasing mechanism.  Called by the user clicking an item on the product list.
+    """
+    # If no user is logged in, redirect to the main page, as a purchase must always be bound to a user
     if 'authenticated_user' not in session_vars:
         return RedirectResponse('/')
+    # Connect to the database
     with MatematDatabase(config['DatabaseFile']) as db:
+        # Fetch the authenticated user from the database
         uid: int = session_vars['authenticated_user']
         user = db.get_user(uid)
+        # Read the product from the database, identified by the product ID passed as request argument
         if 'pid' in args:
             pid = int(str(args.pid))
             product = db.get_product(pid)
+            # Create a consumption entry for the (user, product) combination
             db.increment_consumption(user, product)
+    # Redirect to the main page (where this request should have come from)
     return RedirectResponse('/')

matemat/webserver/pagelets/deposit.py

@@ -12,12 +12,21 @@ def deposit(method: str,
             headers: Dict[str, str],
             config: Dict[str, str]) \
         -> Union[str, bytes, PageletResponse]:
+    """
+    The cash depositing mechanism.  Called by the user submitting a deposit from the product list.
+    """
+    # If no user is logged in, redirect to the main page, as a deposit must always be bound to a user
     if 'authenticated_user' not in session_vars:
         return RedirectResponse('/')
+    # Connect to the database
     with MatematDatabase(config['DatabaseFile']) as db:
+        # Fetch the authenticated user from the database
         uid: int = session_vars['authenticated_user']
         user = db.get_user(uid)
         if 'n' in args:
+            # Read the amount of cash to deposit from the request arguments
             n = int(str(args.n))
+            # Write the deposit to the database
             db.deposit(user, n)
+    # Redirect to the main page (where this request should have come from)
     return RedirectResponse('/')

matemat/webserver/pagelets/login.py

@@ -1,4 +1,3 @@
-
 from typing import Any, Dict, Union
 
 from matemat.exceptions import AuthenticationError, HttpException
@@ -13,20 +12,34 @@ def login_page(method: str,
                args: RequestArguments,
                session_vars: Dict[str, Any],
                headers: Dict[str, str],
-               config: Dict[str, str])\
+               config: Dict[str, str]) \
         -> Union[bytes, str, PageletResponse]:
+    """
+    The password login mechanism.  If called via GET, render the UI template; if called via POST, attempt to log in with
+    the provided credentials (username and passsword).
+    """
+    # If a user is already logged in, simply redirect to the main page, showing the product list
     if 'authenticated_user' in session_vars:
         return RedirectResponse('/')
+    # If requested via HTTP GET, render the login page showing the login UI
     if method == 'GET':
         return TemplateResponse('login.html',
                                 setupname=config['InstanceName'])
+    # If requested via HTTP POST, read the request arguments and attempt to log in with the provided credentials
     elif method == 'POST':
+        # Connect to the database
         with MatematDatabase(config['DatabaseFile']) as db:
             try:
+                # Read the request arguments and attempt to log in with them
                 user: User = db.login(str(args.username), str(args.password))
             except AuthenticationError:
+                # Reload the touchkey login page on failure
                 return RedirectResponse('/login')
+        # Set the user ID session variable
         session_vars['authenticated_user'] = user.id
+        # Set the authlevel session variable (0 = none, 1 = touchkey, 2 = password login)
         session_vars['authentication_level'] = 2
+        # Redirect to the main page, showing the product list
         return RedirectResponse('/')
+    # If neither GET nor POST was used, show a 405 Method Not Allowed error page
     raise HttpException(405)

matemat/webserver/pagelets/logout.py

@@ -1,4 +1,3 @@
-
 from typing import Any, Dict, Union
 
 from matemat.webserver import pagelet, RequestArguments, PageletResponse, RedirectResponse
@@ -10,9 +9,15 @@ def logout(method: str,
            args: RequestArguments,
            session_vars: Dict[str, Any],
            headers: Dict[str, str],
-           config: Dict[str, str])\
+           config: Dict[str, str]) \
         -> Union[bytes, str, PageletResponse]:
+    """
+    The logout mechanism, clearing the authentication values in the session storage.
+    """
+    # Remove the authenticated user ID from the session storage, if any
     if 'authenticated_user' in session_vars:
         del session_vars['authenticated_user']
+    # Reset the authlevel session variable (0 = none, 1 = touchkey, 2 = password login)
     session_vars['authentication_level'] = 0
+    # Redirect to the main page, showing the user list
     return RedirectResponse('/')

matemat/webserver/pagelets/main.py

@@ -1,4 +1,3 @@
-
 from typing import Any, Dict, Union
 
 from matemat.webserver import pagelet, RequestArguments, PageletResponse, TemplateResponse
@@ -11,18 +10,27 @@ def main_page(method: str,
               args: RequestArguments,
               session_vars: Dict[str, Any],
               headers: Dict[str, str],
-              config: Dict[str, str])\
+              config: Dict[str, str]) \
         -> Union[bytes, str, PageletResponse]:
+    """
+    The main page, showing either the user list (if no user is logged in) or the product list (if a user is logged in).
+    """
     with MatematDatabase(config['DatabaseFile']) as db:
+        # Check whether a user is logged in
         if 'authenticated_user' in session_vars:
+            # Fetch the user id and authentication level (touchkey vs password) from the session storage
             uid: int = session_vars['authenticated_user']
             authlevel: int = session_vars['authentication_level']
+            # Fetch the user object from the database (for name display, price calculation and admin check)
             user = db.get_user(uid)
+            # Fetch the list of products to display
             products = db.list_products()
+            # Prepare a response with a jinja2 template
             return TemplateResponse('productlist.html',
                                     authuser=user, products=products, authlevel=authlevel,
                                     setupname=config['InstanceName'])
         else:
+            # If no user is logged in, fetch the list of users and render the userlist template
             users = db.list_users()
             return TemplateResponse('userlist.html',
                                     users=users, setupname=config['InstanceName'])

matemat/webserver/pagelets/modproduct.py

@@ -1,4 +1,3 @@
-
 from typing import Any, Dict, Union
 
 import os
@@ -19,64 +18,102 @@ def modproduct(method: str,
                headers: Dict[str, str],
                config: Dict[str, str]) \
         -> Union[str, bytes, PageletResponse]:
+    """
+    The product modification page available from the admin panel.
+    """
+    # If no user is logged in, redirect to the login page
     if 'authentication_level' not in session_vars or 'authenticated_user' not in session_vars:
         return RedirectResponse('/login')
     authlevel: int = session_vars['authentication_level']
     auth_uid: int = session_vars['authenticated_user']
+    # Show a 403 Forbidden error page if no user is logged in (0) or a user logged in via touchkey (1)
     if authlevel < 2:
         raise HttpException(403)
 
+    # Connect to the database
     with MatematDatabase(config['DatabaseFile']) as db:
+        # Fetch the authenticated user
         authuser = db.get_user(auth_uid)
         if not authuser.is_admin:
+            # Show a 403 Forbidden error page if the user is not an admin
             raise HttpException(403)
         if 'productid' not in args:
+            # Show a 400 Bad Request error page if no product to edit was specified
+            # (should never happen during normal operation)
             raise HttpException(400, '"productid" argument missing')
 
+        # Fetch the product to modify from the database
         modproduct_id = int(str(args.productid))
         product = db.get_product(modproduct_id)
 
+        # If the request contains a "change" parameter, delegate the change handling to the function below
         if 'change' in args:
             handle_change(args, product, db, config)
+            # If the product was deleted, redirect back to the admin page, as there is nothing to edit any more
             if str(args.change) == 'del':
                 return RedirectResponse('/admin')
 
+        # Render the "Modify Product" page
         return TemplateResponse('modproduct.html',
                                 authuser=authuser, product=product, authlevel=authlevel,
                                 setupname=config['InstanceName'])
 
 
 def handle_change(args: RequestArguments, product: Product, db: MatematDatabase, config: Dict[str, str]) -> None:
+    """
+    Write the changes requested by an admin to the database.
+
+    :param args: The RequestArguments object passed to the pagelet.
+    :param product: The product to edit.
+    :param db: The database facade where changes are written to.
+    :param config: The dictionary of config file entries from the [Pagelets] section.
+    """
+    # Read the type of change requested by the admin, then switch over it
     change = str(args.change)
 
+    # Admin requested deletion of the product
     if change == 'del':
+        # Delete the product from the database
         db.delete_product(product)
+        # Delete the product image, if it exists
         try:
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/products/')
             os.remove(os.path.join(abspath, f'{product.id}.png'))
         except FileNotFoundError:
             pass
 
+    # Admin requested update of the product details
     elif change == 'update':
+        # Only write a change if all properties of the product are present in the request arguments
         if 'name' not in args or 'pricemember' not in args or 'pricenonmember' not in args or 'stock' not in args:
             return
+        # Read the properties from the request arguments
         name = str(args.name)
         price_member = parse_chf(str(args.pricemember))
         price_non_member = parse_chf(str(args.pricenonmember))
         stock = int(str(args.stock))
+        # Attempt to write the changes to the database
         try:
             db.change_product(product,
                               name=name, price_member=price_member, price_non_member=price_non_member, stock=stock)
         except DatabaseConsistencyError:
-            pass
+            return
+        # If a new product image was uploaded, process it
         if 'image' in args:
+            # Read the raw image data from the request
             image = bytes(args.image)
+            # Only process the image, if its size is more than zero.  Zero size means no new image was uploaded
+            if len(image) == 0:
+                return
+            # Detect the MIME type
             filemagic: magic.FileMagic = magic.detect_from_content(image)
+            # Currently, only image/png is supported, don't process any other formats
             if filemagic.mime_type != 'image/png':
                 # TODO: Optionally convert to png
                 return
-            if len(image) > 0:
+            # Create the absolute path of the upload directory
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/products/')
             os.makedirs(abspath, exist_ok=True)
+            # Write the image to the file
             with open(os.path.join(abspath, f'{product.id}.png'), 'wb') as f:
                 f.write(image)

matemat/webserver/pagelets/moduser.py

@@ -1,4 +1,3 @@
-
 from typing import Any, Dict, Union
 
 import os
@@ -19,69 +18,113 @@ def moduser(method: str,
             headers: Dict[str, str],
             config: Dict[str, str]) \
         -> Union[str, bytes, PageletResponse]:
+    """
+    The user modification page available from the admin panel.
+    """
+    # If no user is logged in, redirect to the login page
     if 'authentication_level' not in session_vars or 'authenticated_user' not in session_vars:
         return RedirectResponse('/login')
     authlevel: int = session_vars['authentication_level']
     auth_uid: int = session_vars['authenticated_user']
+    # Show a 403 Forbidden error page if no user is logged in (0) or a user logged in via touchkey (1)
     if authlevel < 2:
         raise HttpException(403)
 
+    # Connect to the database
     with MatematDatabase(config['DatabaseFile']) as db:
+        # Fetch the authenticated user
         authuser = db.get_user(auth_uid)
         if not authuser.is_admin:
+            # Show a 403 Forbidden error page if the user is not an admin
             raise HttpException(403)
         if 'userid' not in args:
+            # Show a 400 Bad Request error page if no users to edit was specified
+            # (should never happen during normal operation)
             raise HttpException(400, '"userid" argument missing')
 
+        # Fetch the user to modify from the database
         moduser_id = int(str(args.userid))
         user = db.get_user(moduser_id)
 
+        # If the request contains a "change" parameter, delegate the change handling to the function below
         if 'change' in args:
-            handle_change(args, user, db, config)
+            handle_change(args, user, authuser, db, config)
+            # If the user was deleted, redirect back to the admin page, as there is nothing to edit any more
             if str(args.change) == 'del':
                 return RedirectResponse('/admin')
 
+        # Render the "Modify User" page
         return TemplateResponse('moduser.html',
                                 authuser=authuser, user=user, authlevel=authlevel,
                                 setupname=config['InstanceName'])
 
 
-def handle_change(args: RequestArguments, user: User, db: MatematDatabase, config: Dict[str, str]) -> None:
+def handle_change(args: RequestArguments, user: User, authuser: User, db: MatematDatabase, config: Dict[str, str]) \
+        -> None:
+    """
+    Write the changes requested by an admin to the database.
+
+    :param args: The RequestArguments object passed to the pagelet.
+    :param user: The user to edit.
+    :param authuser: The user performing the modification.
+    :param db: The database facade where changes are written to.
+    :param config: The dictionary of config file entries from the [Pagelets] section.
+    """
+    # Read the type of change requested by the admin, then switch over it
     change = str(args.change)
 
+    # Admin requested deletion of the user
     if change == 'del':
+        # Delete the user from the database
         db.delete_user(user)
+        # Delete the user's avatar, if it exists
         try:
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/users/')
             os.remove(os.path.join(abspath, f'{user.id}.png'))
         except FileNotFoundError:
             pass
 
+    # Admin requested update of the user's details
     elif change == 'update':
+        # Only write a change if all properties of the user are present in the request arguments
         if 'username' not in args or 'email' not in args or 'password' not in args or 'balance' not in args:
             return
+        # Read the properties from the request arguments
         username = str(args.username)
         email = str(args.email)
         password = str(args.password)
         balance = parse_chf(str(args.balance))
         is_member = 'ismember' in args
         is_admin = 'isadmin' in args
+        # An empty e-mail field should be interpreted as NULL
         if len(email) == 0:
             email = None
+        # Attempt to write the changes to the database
         try:
-            db.change_user(user, name=username, email=email, is_member=is_member, is_admin=is_admin, balance=balance)
+            # If a password was entered, replace the password in the database
-        except DatabaseConsistencyError:
-            pass
             if len(password) > 0:
                 db.change_password(user, '', password, verify_password=False)
+            # Write the user detail changes
+            db.change_user(user, agent=authuser, name=username, email=email, is_member=is_member, is_admin=is_admin,
+                           balance=balance)
+        except DatabaseConsistencyError:
+            return
+        # If a new avatar was uploaded, process it
         if 'avatar' in args:
+            # Read the raw image data from the request
             avatar = bytes(args.avatar)
+            # Only process the image, if its size is more than zero.  Zero size means no new image was uploaded
+            if len(avatar) == 0:
+                return
+            # Detect the MIME type
             filemagic: magic.FileMagic = magic.detect_from_content(avatar)
+            # Currently, only image/png is supported, don't process any other formats
             if filemagic.mime_type != 'image/png':
                 # TODO: Optionally convert to png
                 return
-            if len(avatar) > 0:
+            # Create the absolute path of the upload directory
             abspath: str = os.path.join(os.path.abspath(config['UploadDir']), 'thumbnails/users/')
             os.makedirs(abspath, exist_ok=True)
+            # Write the image to the file
             with open(os.path.join(abspath, f'{user.id}.png'), 'wb') as f:
                 f.write(avatar)

matemat/webserver/pagelets/touchkey.py

@@ -1,4 +1,3 @@
-
 from typing import Any, Dict, Union
 
 from matemat.exceptions import AuthenticationError, HttpException
@@ -13,21 +12,35 @@ def touchkey_page(method: str,
                   args: RequestArguments,
                   session_vars: Dict[str, Any],
                   headers: Dict[str, str],
-                  config: Dict[str, str])\
+                  config: Dict[str, str]) \
         -> Union[bytes, str, PageletResponse]:
+    """
+    The touchkey login mechanism.  If called via GET, render the UI template; if called via POST, attempt to log in with
+    the provided credentials (username and touchkey).
+    """
+    # If a user is already logged in, simply redirect to the main page, showing the product list
     if 'authenticated_user' in session_vars:
         return RedirectResponse('/')
+    # If requested via HTTP GET, render the login page showing the touchkey UI
     if method == 'GET':
         return TemplateResponse('touchkey.html',
                                 username=str(args.username), uid=int(str(args.uid)),
                                 setupname=config['InstanceName'])
+    # If requested via HTTP POST, read the request arguments and attempt to log in with the provided credentials
     elif method == 'POST':
+        # Connect to the database
         with MatematDatabase(config['DatabaseFile']) as db:
             try:
+                # Read the request arguments and attempt to log in with them
                 user: User = db.login(str(args.username), touchkey=str(args.touchkey))
             except AuthenticationError:
+                # Reload the touchkey login page on failure
                 return RedirectResponse(f'/touchkey?uid={str(args.uid)}&username={str(args.username)}')
+        # Set the user ID session variable
         session_vars['authenticated_user'] = user.id
+        # Set the authlevel session variable (0 = none, 1 = touchkey, 2 = password login)
         session_vars['authentication_level'] = 1
+        # Redirect to the main page, showing the product list
         return RedirectResponse('/')
+    # If neither GET nor POST was used, show a 405 Method Not Allowed error page
     raise HttpException(405)

templates/admin.html

@@ -1,22 +1,25 @@
 {% extends "base.html" %}
 
 {% block header %}
-{% if authuser.is_admin %}
+    {# If the logged in user is an administrator, call the title "Administration", otherwise "Settings" #}
-<h1>Administration</h1>
+    {% if authuser.is_admin %}
-{% else %}
+        <h1>Administration</h1>
-<h1>Settings</h1>
+    {% else %}
-{% endif %}
+        <h1>Settings</h1>
-{{ super() }}
+    {% endif %}
+    {{ super() }}
 {% endblock %}
 
 {% block main %}
 
-{% include "admin_all.html" %}
+    {# Always show the settings a user can edit for itself #}
+    {% include "admin_all.html" %}
 
-{% if authuser.is_admin %}
+    {# Only show the "restricted" section if the user is an admin #}
-{% include "admin_restricted.html" %}
+    {% if authuser.is_admin %}
-{% endif %}
+        {% include "admin_restricted.html" %}
+    {% endif %}
 
-{{ super() }}
+    {{ super() }}
 
 {% endblock %}

templates/base.html

@@ -1,18 +1,25 @@
 <!DOCTYPE html>
 <html>
+
 <head>
     {% block head %}
+        {# Show the setup name, as set in the config file, as tab title. Don't escape HTML entities. #}
         <title>{{ setupname|safe }}</title>
-    <link rel="stylesheet" href="/css/matemat.css" />
+        <link rel="stylesheet" href="/css/matemat.css"/>
     {% endblock %}
 </head>
+
 <body>
+
 <header>
     {% block header %}
 
+        {# Always show a link to the home page, either a list of users or of products. #}
         <a href="/">Home</a>
+        {# Show a link to the settings, if a user logged in via password (authlevel 2). #}
         {% if authlevel|default(0) > 1 %}
             {% if authuser is defined %}
+                {# If a user is an admin, call the link "Administration".  Otherwise, call it "Settings". #}
                 {% if authuser.is_admin %}
                     <a href="/admin">Administration</a>
                 {% else %}
@@ -22,18 +29,27 @@
         {% endif %}
     {% endblock %}
 </header>
+
 <main>
-    {% block main %}{% endblock %}
+    {% block main %}
+        {# Here be content. #}
+    {% endblock %}
 </main>
+
 <footer>
     {% block footer %}
+        {# Show some information in the footer, e.g. the instance name, the version, and copyright info. #}
         <ul>
             <li> {{ setupname|safe }}
-        <li> Matemat {{__version__}}
+            <li> Matemat {{ __version__ }}
             <li> &copy; 2018 s3lph
             <li> MIT License
+                {# This used to be a link to the GitLab repo.  However, users of the testing environment always clicked
+                that link and couldn't come back, because the UI was running in touch-only kiosk mode. #}
+            <li> gitlab.com/s3lph/matemat
         </ul>
     {% endblock %}
 </footer>
+
 </body>
 </html>

templates/login.html

@@ -1,23 +1,23 @@
 {% extends "base.html" %}
 
-
 {% block header %}
-<h1>Welcome</h1>
+    <h1>Welcome</h1>
-{{ super() }}
+    {{ super() }}
 {% endblock %}
 
 {% block main %}
 
-<form method="post" action="/login" id="loginform" accept-charset="UTF-8">
+    {# Show a username/password login form #}
+    <form method="post" action="/login" id="loginform" accept-charset="UTF-8">
         <label for="login-username">Username: </label>
-    <input id="login-username" type="text" name="username" /><br/>
+        <input id="login-username" type="text" name="username"/><br/>
 
         <label for="login-password">Password: </label>
-    <input id="login-password" type="password" name="password" /><br/>
+        <input id="login-password" type="password" name="password"/><br/>
 
         <input type="submit" value="Login">
-</form>
+    </form>
 
-{{ super() }}
+    {{ super() }}
 
 {% endblock %}

templates/productlist.html

@@ -1,21 +1,23 @@
 {% extends "base.html" %}
 
 {% block header %}
-<h1>Welcome, {{ authuser.name }}</h1>
+    {# Show the username. #}
-
+    <h1>Welcome, {{ authuser.name }}</h1>
-{{ super() }}
+    {{ super() }}
-
 {% endblock %}
 
 {% block main %}
 
-Your balance: {{ authuser.balance|chf }}
+    {# Show the users current balance #}
-<br/>
+    Your balance: {{ authuser.balance|chf }}
-<a href="/deposit?n=100">Deposit CHF 1</a><br/>
+    <br/>
-<a href="/deposit?n=1000">Deposit CHF 10</a><br/>
+    {# Links to deposit two common amounts of cash.  TODO: Will be replaced by a nicer UI later (#20) #}
+    <a href="/deposit?n=100">Deposit CHF 1</a><br/>
+    <a href="/deposit?n=1000">Deposit CHF 10</a><br/>
 
-{% for product in products %}
+    {% for product in products %}
-<div class="thumblist-item">
+        {# Show an item per product, consisting of the name, image, price and stock, triggering a purchase on click #}
+        <div class="thumblist-item">
             <a href="/buy?pid={{ product.id }}">
                 <span class="thumblist-title">{{ product.name }}</span>
                 <span class="thumblist-detail">Price:
@@ -26,14 +28,15 @@ Your balance: {{ authuser.balance|chf }}
                     {% endif %}
                     ; Stock: {{ product.stock }}</span><br/>
                 <div class="imgcontainer">
-            <img src="/upload/thumbnails/products/{{ product.id }}.png" alt="Picture of {{ product.name }}" />
+                    <img src="/upload/thumbnails/products/{{ product.id }}.png" alt="Picture of {{ product.name }}"/>
                 </div>
             </a>
-</div>
+        </div>
-{% endfor %}
+    {% endfor %}
-<br/>
+    <br/>
-<a href="/logout">Logout</a>
+    {# Logout link #}
+    <a href="/logout">Logout</a>
 
-{{ super() }}
+    {{ super() }}
 
 {% endblock %}

templates/userlist.html

@@ -1,22 +1,29 @@
 {% extends "base.html" %}
 
 {% block header %}
-<h1>{{ setupname }}</h1>
+    {# Show the setup name, as set in the config file, as page title. Don't escape HTML entities. #}
-{{ super() }}
+    <h1>{{ setupname|safe }}</h1>
+    {{ super() }}
 {% endblock %}
 
 {% block main %}
-{% for user in users %}
+
-<div class="thumblist-item">
+    {% for user in users %}
+        {# Show an item per user, consisting of the username, and the avatar, linking to the touchkey login #}
+        <div class="thumblist-item">
             <a href="/touchkey?uid={{ user.id }}&username={{ user.name }}">
                 <span class="thumblist-title">{{ user.name }}</span><br/>
                 <div class="imgcontainer">
-            <img src="/upload/thumbnails/users/{{ user.id }}.png" alt="Avatar of {{ user.name }}" />
+                    <img src="/upload/thumbnails/users/{{ user.id }}.png" alt="Avatar of {{ user.name }}"/>
                 </div>
             </a>
-</div>
+        </div>
-{% endfor %}
+    {% endfor %}
-<br/>
+
-<a href="/login">Password-based login</a>
+    <br/>
-{{ super() }}
+    {# Link to the password login #}
+    <a href="/login">Password login</a>
+
+    {{ super() }}
+
 {% endblock %}