Add pluggable interfaces for providing stock information or dispensing physical products

CHANGELOG.md

@@ -1,5 +1,20 @@
 # Matemat Changelog
 
+<!-- BEGIN RELEASE v0.2.5 -->
+## Version 0.2.5
+
+Feature release
+
+### Changes
+
+<!-- BEGIN CHANGES 0.2.5 -->
+- Feature: Non-stockable products
+- Feature: Pluggable stock provider and dispenser modules
+- Fix: Products creation raised an error if no image was uploaded
+<!-- END CHANGES 0.2.5 -->
+
+<!-- END RELEASE v0.2.5 -->
+
 <!-- BEGIN RELEASE v0.2.4 -->
 ## Version 0.2.4
 

matemat/__init__.py

@@ -1,2 +1,2 @@
 
-__version__ = '0.2.4'
+__version__ = '0.2.5'

matemat/db/facade.py

@@ -354,11 +354,11 @@ class MatematDatabase(object):
         products: List[Product] = []
         with self.db.transaction(exclusive=False) as c:
             for row in c.execute('''
-                SELECT product_id, name, price_member, price_non_member, stock
+                SELECT product_id, name, price_member, price_non_member, stock, stockable
                 FROM products
               '''):
-                product_id, name, price_member, price_external, stock = row
+                product_id, name, price_member, price_external, stock, stockable = row
-                products.append(Product(product_id, name, price_member, price_external, stock))
+                products.append(Product(product_id, name, price_member, price_external, stockable, stock))
         return products
 
     def get_product(self, pid: int) -> Product:
@@ -369,7 +369,7 @@ class MatematDatabase(object):
         with self.db.transaction(exclusive=False) as c:
             # Fetch all values to construct the product
             c.execute('''
-                SELECT product_id, name, price_member, price_non_member, stock
+                SELECT product_id, name, price_member, price_non_member, stock, stockable
                 FROM products
                 WHERE product_id = ?''',
                       [pid])
@@ -377,15 +377,16 @@ class MatematDatabase(object):
             if row is None:
                 raise ValueError(f'No product with product ID {pid} exists.')
             # Unpack the row and construct the product
-            product_id, name, price_member, price_non_member, stock = row
+            product_id, name, price_member, price_non_member, stock, stockable = row
-            return Product(product_id, name, price_member, price_non_member, stock)
+            return Product(product_id, name, price_member, price_non_member, stockable, stock)
 
-    def create_product(self, name: str, price_member: int, price_non_member: int) -> Product:
+    def create_product(self, name: str, price_member: int, price_non_member: int, stockable: bool) -> Product:
         """
         Creates a new product.
         :param name: Name of the product.
         :param price_member: Price of the product for members.
         :param price_non_member: Price of the product for non-members.
+        :param stockable: True if the product should be stockable, false otherwise.
         :return: A Product object representing the created product.
         :raises ValueError: If a product with the same name already exists.
         """
@@ -395,16 +396,17 @@ class MatematDatabase(object):
             if c.fetchone() is not None:
                 raise ValueError(f'A product with the name \'{name}\' already exists.')
             c.execute('''
-              INSERT INTO products (name, price_member, price_non_member, stock)
+              INSERT INTO products (name, price_member, price_non_member, stock, stockable)
-              VALUES (:name, :price_member, :price_non_member, 0)
+              VALUES (:name, :price_member, :price_non_member, 0, :stockable)
             ''', {
                 'name': name,
                 'price_member': price_member,
-                'price_non_member': price_non_member
+                'price_non_member': price_non_member,
+                'stockable': stockable
             })
             c.execute('SELECT last_insert_rowid()')
             product_id = int(c.fetchone()[0])
-        return Product(product_id, name, price_member, price_non_member, 0)
+        return Product(product_id, name, price_member, price_non_member, stockable, 0)
 
     def change_product(self, product: Product, **kwargs) -> None:
         """
@@ -421,6 +423,7 @@ class MatematDatabase(object):
         price_member: int = kwargs['price_member'] if 'price_member' in kwargs else product.price_member
         price_non_member: int = kwargs['price_non_member'] if 'price_non_member' in kwargs else product.price_non_member
         stock: int = kwargs['stock'] if 'stock' in kwargs else product.stock
+        stockable: bool = kwargs['stockable'] if 'stockable' in kwargs else product.stockable
         with self.db.transaction() as c:
             c.execute('''
             UPDATE products
@@ -428,14 +431,16 @@ class MatematDatabase(object):
               name = :name,
               price_member = :price_member,
               price_non_member = :price_non_member,
-              stock = :stock
+              stock = :stock,
+              stockable = :stockable
             WHERE product_id = :product_id
             ''', {
                 'product_id': product.id,
                 'name': name,
                 'price_member': price_member,
                 'price_non_member': price_non_member,
-                'stock': stock
+                'stock': stock,
+                'stockable': stockable
             })
             affected = c.execute('SELECT changes()').fetchone()[0]
             if affected != 1:
@@ -446,6 +451,7 @@ class MatematDatabase(object):
         product.price_member = price_member
         product.price_non_member = price_non_member
         product.stock = stock
+        product.stockable = stockable
 
     def delete_product(self, product: Product) -> None:
         """
@@ -501,44 +507,8 @@ class MatematDatabase(object):
             if affected != 1:
                 raise DatabaseConsistencyError(
                     f'increment_consumption should affect 1 users row, but affected {affected}')
-            # Subtract the number of purchased units from the product's stock.
-            c.execute('''
-            UPDATE products
-            SET stock = stock - 1
-            WHERE product_id = :product_id
-            ''', {
-                'product_id': product.id,
-            })
-            # Make sure exactly one product row was updated.
-            affected = c.execute('SELECT changes()').fetchone()[0]
-            if affected != 1:
-                raise DatabaseConsistencyError(
-                    f'increment_consumption should affect 1 products row, but affected {affected}')
         # Reflect the change in the user and product objects
         user.balance -= price
-        product.stock -= 1
-
-    def restock(self, product: Product, count: int) -> None:
-        """
-        Update the stock of a product.
-        :param product: The product to restock.
-        :param count: Number of units of the product to add.
-        :raises DatabaseConsistencyError: If the product represented by the object does not exist.
-        """
-        with self.db.transaction() as c:
-            c.execute('''
-            UPDATE products
-            SET stock = stock + :count
-            WHERE product_id = :product_id
-            ''', {
-                'product_id': product.id,
-                'count': count
-            })
-            affected = c.execute('SELECT changes()').fetchone()[0]
-            if affected != 1:
-                raise DatabaseConsistencyError(f'restock should affect 1 products row, but affected {affected}')
-        # Reflect the change in the product object
-        product.stock += count
 
     def deposit(self, user: User, amount: int) -> None:
         """

matemat/db/migrations.py

@@ -239,3 +239,32 @@ def migrate_schema_3_to_4(c: sqlite3.Cursor):
     ''')
     c.execute('INSERT INTO receipts SELECT * FROM receipts_temp')
     c.execute('DROP TABLE receipts_temp')
+
+
+def migrate_schema_4_to_5(c: sqlite3.Cursor):
+    # Change products schema to allow null for stock and add stockable column
+    c.execute('''
+    CREATE TEMPORARY TABLE products_temp (
+      product_id INTEGER PRIMARY KEY,
+      name TEXT UNIQUE NOT NULL,
+      stock INTEGER(8) NOT NULL DEFAULT 0,
+      price_member INTEGER(8) NOT NULL,
+      price_non_member INTEGER(8) NOT NULL
+    );
+    ''')
+    c.execute('INSERT INTO products_temp SELECT * FROM products')
+    c.execute('DROP TABLE products')
+    c.execute('''
+    CREATE TABLE products (
+      product_id INTEGER PRIMARY KEY,
+      name TEXT UNIQUE NOT NULL,
+      stock INTEGER(8) DEFAULT 0,
+      stockable INTEGER(1) DEFAULT 1,
+      price_member INTEGER(8) NOT NULL,
+      price_non_member INTEGER(8) NOT NULL
+    );
+    ''')
+    c.execute('''
+    INSERT INTO products SELECT product_id, name, stock, 1, price_member, price_non_member FROM products_temp
+    ''')
+    c.execute('DROP TABLE products_temp')

matemat/db/primitives/Product.py

@@ -8,15 +8,19 @@ class Product:
     :param name: The product's name.
     :param price_member: The price of a unit of this product for users marked as "members".
     :param price_non_member: The price of a unit of this product for users NOT marked as "members".
-    :param stock: The number of items of this product currently in stock.
+    :param stock: The number of items of this product currently in stock, or None if not stockable.
+    :param stockable: Whether this product is stockable.
     """
 
-    def __init__(self, _id: int, name: str, price_member: int, price_non_member: int, stock: int) -> None:
+    def __init__(self, _id: int, name: str,
+                 price_member: int, price_non_member: int,
+                 stockable: bool, stock: int) -> None:
         self.id: int = _id
         self.name: str = name
         self.price_member: int = price_member
         self.price_non_member: int = price_non_member
         self.stock: int = stock
+        self.stockable: bool = stockable
 
     def __eq__(self, other) -> bool:
         if not isinstance(other, Product):
@@ -25,7 +29,8 @@ class Product:
             self.name == other.name and \
             self.price_member == other.price_member and \
             self.price_non_member == other.price_non_member and \
-            self.stock == other.stock
+            self.stock == other.stock and \
+            self.stockable == other.stockable
 
     def __hash__(self) -> int:
-        return hash((self.id, self.name, self.price_member, self.price_non_member, self.stock))
+        return hash((self.id, self.name, self.price_member, self.price_non_member, self.stock, self.stockable))

matemat/db/schemas.py

@@ -255,3 +255,82 @@ SCHEMAS[4] = [
         ON DELETE SET NULL ON UPDATE CASCADE
     );
     ''']
+
+SCHEMAS[5] = [
+    '''
+    CREATE TABLE users (
+      user_id INTEGER PRIMARY KEY,
+      username TEXT UNIQUE NOT NULL,
+      email TEXT DEFAULT NULL,
+      password TEXT NOT NULL,
+      touchkey TEXT DEFAULT NULL,
+      is_admin INTEGER(1) NOT NULL DEFAULT 0,
+      is_member INTEGER(1) NOT NULL DEFAULT 1,
+      balance INTEGER(8) NOT NULL DEFAULT 0,
+      lastchange INTEGER(8) NOT NULL DEFAULT 0,
+      receipt_pref INTEGER(1) NOT NULL DEFAULT 0,
+      created INTEGER(8) NOT NULL DEFAULT 0
+    );
+    ''',
+    '''
+    CREATE TABLE products (
+      product_id INTEGER PRIMARY KEY,
+      name TEXT UNIQUE NOT NULL,
+      stock INTEGER(8) DEFAULT 0,
+      stockable INTEGER(1) DEFAULT 1,
+      price_member INTEGER(8) NOT NULL,
+      price_non_member INTEGER(8) NOT NULL
+    );
+    ''',
+    '''
+    CREATE TABLE transactions (  -- "superclass" of the following 3 tables
+      ta_id INTEGER PRIMARY KEY,
+      user_id INTEGER DEFAULT NULL,
+      value INTEGER(8) NOT NULL,
+      old_balance INTEGER(8) NOT NULL,
+      date INTEGER(8) DEFAULT (STRFTIME('%s', 'now')),
+      FOREIGN KEY (user_id) REFERENCES users(user_id)
+        ON DELETE SET NULL ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE consumptions (  -- transactions involving buying a product
+      ta_id INTEGER PRIMARY KEY,
+      product TEXT NOT NULL,
+      FOREIGN KEY (ta_id) REFERENCES transactions(ta_id)
+        ON DELETE CASCADE ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE deposits (  -- transactions involving depositing cash
+      ta_id INTEGER PRIMARY KEY,
+      FOREIGN KEY (ta_id) REFERENCES transactions(ta_id)
+        ON DELETE CASCADE ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE modifications (  -- transactions involving balance modification by an admin
+      ta_id INTEGER NOT NULL,
+      agent TEXT NOT NULL,
+      reason TEXT DEFAULT NULL,
+      PRIMARY KEY (ta_id),
+      FOREIGN KEY (ta_id) REFERENCES transactions(ta_id)
+        ON DELETE CASCADE ON UPDATE CASCADE
+    );
+    ''',
+    '''
+    CREATE TABLE receipts (  -- receipts sent to the users
+      receipt_id INTEGER PRIMARY KEY,
+      user_id INTEGER NOT NULL,
+      first_ta_id INTEGER DEFAULT NULL,
+      last_ta_id INTEGER DEFAULT NULL,
+      date INTEGER(8) DEFAULT (STRFTIME('%s', 'now')),
+      FOREIGN KEY (user_id) REFERENCES users(user_id)
+        ON DELETE CASCADE ON UPDATE CASCADE,
+      FOREIGN KEY (first_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE,
+      FOREIGN KEY (last_ta_id) REFERENCES transactions(ta_id)
+        ON DELETE SET NULL ON UPDATE CASCADE
+    );
+    ''']
+

matemat/db/test/test_facade.py

@@ -220,24 +220,26 @@ class DatabaseTest(unittest.TestCase):
     def test_create_product(self) -> None:
         with self.db as db:
             with db.transaction() as c:
-                db.create_product('Club Mate', 200, 200)
+                db.create_product('Club Mate', 200, 200, True)
                 c.execute("SELECT * FROM products")
                 row = c.fetchone()
                 self.assertEqual('Club Mate', row[1])
                 self.assertEqual(0, row[2])
-                self.assertEqual(200, row[3])
+                self.assertEqual(1, row[3])
                 self.assertEqual(200, row[4])
+                self.assertEqual(200, row[5])
             with self.assertRaises(ValueError):
-                db.create_product('Club Mate', 250, 250)
+                db.create_product('Club Mate', 250, 250, False)
 
     def test_get_product(self) -> None:
         with self.db as db:
             with db.transaction(exclusive=False):
-                created = db.create_product('Club Mate', 150, 250)
+                created = db.create_product('Club Mate', 150, 250, False)
                 product = db.get_product(created.id)
                 self.assertEqual('Club Mate', product.name)
                 self.assertEqual(150, product.price_member)
                 self.assertEqual(250, product.price_non_member)
+                self.assertEqual(False, product.stockable)
                 with self.assertRaises(ValueError):
                     db.get_product(-1)
 
@@ -246,9 +248,9 @@ class DatabaseTest(unittest.TestCase):
             # Test empty list
             products = db.list_products()
             self.assertEqual(0, len(products))
-            db.create_product('Club Mate', 200, 200)
+            db.create_product('Club Mate', 200, 200, True)
-            db.create_product('Flora Power Mate', 200, 200)
+            db.create_product('Flora Power Mate', 200, 200, False)
-            db.create_product('Fritz Mate', 200, 250)
+            db.create_product('Fritz Mate', 200, 250, True)
             products = db.list_products()
             self.assertEqual(3, len(products))
         productcheck = {}
@@ -256,34 +258,39 @@ class DatabaseTest(unittest.TestCase):
             if product.name == 'Club Mate':
                 self.assertEqual(200, product.price_member)
                 self.assertEqual(200, product.price_non_member)
+                self.assertTrue(product.stockable)
             elif product.name == 'Flora Power Mate':
                 self.assertEqual(200, product.price_member)
                 self.assertEqual(200, product.price_non_member)
+                self.assertFalse(product.stockable)
             elif product.name == 'Fritz Mate':
                 self.assertEqual(200, product.price_member)
                 self.assertEqual(250, product.price_non_member)
+                self.assertTrue(product.stockable)
             productcheck[product.id] = 1
         self.assertEqual(3, len(productcheck))
 
     def test_change_product(self) -> None:
         with self.db as db:
-            product = db.create_product('Club Mate', 200, 200)
+            product = db.create_product('Club Mate', 200, 200, True)
-            db.change_product(product, name='Flora Power Mate', price_member=150, price_non_member=250, stock=42)
+            db.change_product(product, name='Flora Power Mate', price_member=150, price_non_member=250,
+                              stock=None, stockable=False)
             # Changes must be reflected in the passed object
             self.assertEqual('Flora Power Mate', product.name)
             self.assertEqual(150, product.price_member)
             self.assertEqual(250, product.price_non_member)
             self.assertEqual(42, product.stock)
+            self.assertEqual(False, product.stockable)
             # Changes must be reflected in the database
             checkproduct = db.get_product(product.id)
             self.assertEqual('Flora Power Mate', checkproduct.name)
             self.assertEqual(150, checkproduct.price_member)
             self.assertEqual(250, checkproduct.price_non_member)
-            self.assertEqual(42, checkproduct.stock)
+            self.assertEqual(None, checkproduct.stock)
             product.id = -1
             with self.assertRaises(DatabaseConsistencyError):
                 db.change_product(product)
-            product2 = db.create_product('Club Mate', 200, 200)
+            product2 = db.create_product('Club Mate', 200, 200, True)
             product2.name = 'Flora Power Mate'
             with self.assertRaises(DatabaseConsistencyError):
                 # Should fail, as a product with the same name already exists.
@@ -291,8 +298,8 @@ class DatabaseTest(unittest.TestCase):
 
     def test_delete_product(self) -> None:
         with self.db as db:
-            product = db.create_product('Club Mate', 200, 200)
+            product = db.create_product('Club Mate', 200, 200, True)
-            product2 = db.create_product('Flora Power Mate', 200, 200)
+            product2 = db.create_product('Flora Power Mate', 200, 200, False)
 
             self.assertEqual(2, len(db.list_products()))
             db.delete_product(product)
@@ -328,25 +335,6 @@ class DatabaseTest(unittest.TestCase):
                     # Should fail, user id -1 does not exist
                     db.deposit(user, 42)
 
-    def test_restock(self) -> None:
-        with self.db as db:
-            with db.transaction() as c:
-                product = db.create_product('Club Mate', 200, 200)
-                product2 = db.create_product('Flora Power Mate', 200, 200)
-                c.execute('''SELECT stock FROM products WHERE product_id = ?''', [product.id])
-                self.assertEqual(0, c.fetchone()[0])
-                c.execute('''SELECT stock FROM products WHERE product_id = ?''', [product2.id])
-                self.assertEqual(0, c.fetchone()[0])
-                db.restock(product, 42)
-                c.execute('''SELECT stock FROM products WHERE product_id = ?''', [product.id])
-                self.assertEqual(42, c.fetchone()[0])
-                c.execute('''SELECT stock FROM products WHERE product_id = ?''', [product2.id])
-                self.assertEqual(0, c.fetchone()[0])
-                product.id = -1
-                with self.assertRaises(DatabaseConsistencyError):
-                    # Should fail, product id -1 does not exist
-                    db.restock(product, 42)
-
     def test_consumption(self) -> None:
         with self.db as db:
             # Set up test case
@@ -356,12 +344,9 @@ class DatabaseTest(unittest.TestCase):
             db.deposit(user1, 1337)
             db.deposit(user2, 4242)
             db.deposit(user3, 1234)
-            clubmate = db.create_product('Club Mate', 200, 200)
+            clubmate = db.create_product('Club Mate', 200, 200, True)
-            florapowermate = db.create_product('Flora Power Mate', 150, 250)
+            florapowermate = db.create_product('Flora Power Mate', 150, 250, True)
-            fritzmate = db.create_product('Fritz Mate', 200, 200)
+            fritzmate = db.create_product('Fritz Mate', 200, 200, True)
-            db.restock(clubmate, 50)
-            db.restock(florapowermate, 70)
-            db.restock(fritzmate, 10)
 
             # user1 is somewhat addicted to caffeine
             for _ in range(3):
@@ -381,13 +366,6 @@ class DatabaseTest(unittest.TestCase):
                 c.execute('''SELECT balance FROM users WHERE user_id = ?''', [user3.id])
                 self.assertEqual(1234, c.fetchone()[0])
 
-                c.execute('''SELECT stock FROM products WHERE product_id = ?''', [clubmate.id])
-                self.assertEqual(40, c.fetchone()[0])
-                c.execute('''SELECT stock FROM products WHERE product_id = ?''', [florapowermate.id])
-                self.assertEqual(60, c.fetchone()[0])
-                c.execute('''SELECT stock FROM products WHERE product_id = ?''', [fritzmate.id])
-                self.assertEqual(10, c.fetchone()[0])
-
             user1.id = -1
             clubmate.id = -1
             with self.assertRaises(DatabaseConsistencyError):

matemat/db/wrapper.py

@@ -40,7 +40,7 @@ class DatabaseTransaction(object):
 
 class DatabaseWrapper(object):
 
-    SCHEMA_VERSION = 4
+    SCHEMA_VERSION = 5
 
     def __init__(self, filename: str) -> None:
         self._filename: str = filename
@@ -85,6 +85,8 @@ class DatabaseWrapper(object):
                 migrate_schema_2_to_3(c)
             if from_version <= 3 and to_version >= 4:
                 migrate_schema_3_to_4(c)
+            if from_version <= 4 and to_version >= 5:
+                migrate_schema_4_to_5(c)
 
     def connect(self) -> None:
         if self.is_connected():

matemat/interfacing/dispenser/__init__.py

@@ -0,0 +1,3 @@
+
+from .dispenser import Dispenser
+from .nulldispenser import NullDispenser

matemat/interfacing/dispenser/dispenser.py

@@ -0,0 +1,6 @@
+
+
+class Dispenser:
+
+    def dispense(self, product, amount):
+        pass

matemat/interfacing/dispenser/nulldispenser.py

@@ -0,0 +1,8 @@
+from matemat.interfacing.dispenser import Dispenser
+
+
+class NullDispenser(Dispenser):
+
+    def dispense(self, product, amount):
+        # no-op
+        pass

matemat/interfacing/stock/__init__.py

@@ -0,0 +1,3 @@
+
+from .stockprovider import StockProvider
+from .databasestockprovider import DatabaseStockProvider

matemat/interfacing/stock/databasestockprovider.py

@@ -0,0 +1,32 @@
+from typing import Optional
+
+from matemat.db import MatematDatabase
+from matemat.db.primitives.Product import Product
+from matemat.interfacing.stock import StockProvider
+from matemat.webserver.config import get_app_config
+
+
+class DatabaseStockProvider(StockProvider):
+
+    @classmethod
+    def needs_update(cls) -> bool:
+        return True
+
+    def get_stock(self, product: Product) -> Optional[int]:
+        if not product.stockable:
+            return None
+        return product.stock
+
+    def set_stock(self, product: Product, stock: int) -> None:
+        if product.stock is None or not product.stockable:
+            return
+        config = get_app_config()
+        with MatematDatabase(config['DatabaseFile']) as db:
+            db.change_product(product, stock=stock)
+
+    def update_stock(self, product: Product, stock: int) -> None:
+        if product.stock is None or not product.stockable:
+            return
+        config = get_app_config()
+        with MatematDatabase(config['DatabaseFile']) as db:
+            db.change_product(product, stock=product.stock + stock)

matemat/interfacing/stock/stockprovider.py

@@ -0,0 +1,40 @@
+
+from typing import Optional
+
+from matemat.db.primitives.Product import Product
+
+
+class StockProvider:
+
+    @classmethod
+    def needs_update(cls) -> bool:
+        """
+        If this method returns True, `set_stock` and `update_stock` MUST be implemented.
+        If this method returns False, `set_stock` or `update_stock` will never be called.
+        :return: True if state needs to be updated, false otherwise.
+        """
+        return False
+
+    def get_stock(self, product: Product) -> Optional[int]:
+        """
+        Returns the number of items in stock, if supported.
+        :param product: The product to get the stock for.
+        :return: Number of items in stock, or None if not supported.
+        """
+        pass
+
+    def set_stock(self, product: Product, stock: int):
+        """
+        Sets the number of items in stock, if supported.
+        :param product: The product to set the stock for.
+        :param stock: The amount to set the stock to.
+        """
+        pass
+
+    def update_stock(self, product: Product, stock: int) -> None:
+        """
+        Increases or decreases the number of items in stock, if supported.
+        :param product: The product to update the stock for.
+        :param stock: The amount to add to or subtract from the stock.
+        """
+        pass

matemat/webserver/config.py

@@ -4,10 +4,12 @@ from typing import Any, Dict, Iterable, List, Tuple, Union
 import os
 import sys
 import logging
+import importlib
 from configparser import ConfigParser
 
-
 config: Dict[str, Any] = dict()
+stock_provider = None
+dispenser = None
 
 
 def parse_logging(symbolic_level: str, symbolic_target: str) -> Tuple[int, logging.Handler]:
@@ -74,6 +76,8 @@ def parse_config_file(paths: Union[str, Iterable[str]]) -> None:
     config['pagelet_variables'] = dict()
     # Statically configured headers
     config['headers'] = dict()
+    # Pluggable interface config
+    config['interfaces'] = dict()
 
     # Initialize the config parser
     parser: ConfigParser = ConfigParser()
@@ -111,6 +115,11 @@ def parse_config_file(paths: Union[str, Iterable[str]]) -> None:
         for k, v in parser['HttpHeaders'].items():
             config['headers'][k] = v
 
+    # Read all values from the [Providers] section, if present.  These values are set as HTTP response headers
+    if 'Interfaces' in parser.sections():
+        for k, v in parser['Interfaces'].items():
+            config['interfaces'][k] = v
+
 
 def get_config() -> Dict[str, Any]:
     global config
@@ -120,3 +129,27 @@ def get_config() -> Dict[str, Any]:
 def get_app_config() -> Dict[str, Any]:
     global config
     return config['pagelet_variables']
+
+
+def get_stock_provider() -> 'StockProvider':
+    global config, stock_provider
+    if stock_provider is None:
+        providers = config.get('interfaces', {})
+        fqcn = providers.get('StockProvider', 'matemat.interfacing.stock.DatabaseStockProvider')
+        modname, clsname = fqcn.rsplit('.', 1)
+        module = importlib.import_module(modname)
+        cls = getattr(module, clsname)
+        stock_provider = cls()
+    return stock_provider
+
+
+def get_dispenser() -> 'Dispenser':
+    global config, dispenser
+    if dispenser is None:
+        providers = config.get('interfaces', {})
+        fqcn = providers.get('Dispenser', 'matemat.interfacing.dispenser.NullDispenser')
+        modname, clsname = fqcn.rsplit('.', 1)
+        module = importlib.import_module(modname)
+        cls = getattr(module, clsname)
+        dispenser = cls()
+    return dispenser

matemat/webserver/pagelets/admin.py

@@ -11,7 +11,7 @@ from matemat.db.primitives import User, ReceiptPreference
 from matemat.exceptions import AuthenticationError, DatabaseConsistencyError
 from matemat.util.currency_format import parse_chf
 from matemat.webserver import session, template
-from matemat.webserver.config import get_app_config
+from matemat.webserver.config import get_app_config, get_stock_provider
 
 
 @get('/admin')
@@ -191,17 +191,19 @@ def handle_admin_change(args: FormsDict, files: FormsDict, db: MatematDatabase):
         # 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:
+            for key in ['name','pricemember', 'pricenonmember']:
-                return
+                if key 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))
+            stockable = 'stockable' in args
             # Create the user in the database
-            newproduct = db.create_product(name, price_member, price_non_member)
+            newproduct = db.create_product(name, price_member, price_non_member, stockable)
             # If a new product image was uploaded, process it
             image = files.image.file.read() if 'image' in files else None
-            if image is None or len(image) == 0:
+            if image is not None and len(image) > 0:
                 # Detect the MIME type
                 filemagic: magic.FileMagic = magic.detect_from_content(image)
                 if not filemagic.mime_type.startswith('image/'):
@@ -232,6 +234,9 @@ def handle_admin_change(args: FormsDict, files: FormsDict, db: MatematDatabase):
 
         # The user requested to restock a product
         elif change == 'restock':
+            stock_provider = get_stock_provider()
+            if not stock_provider.needs_update():
+                return
             # 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
@@ -240,8 +245,9 @@ def handle_admin_change(args: FormsDict, files: FormsDict, db: MatematDatabase):
             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
+            if not product.stockable:
-            db.restock(product, amount)
+                return
+            stock_provider.update_stock(product, amount)
 
         # The user requested to set default images
         elif change == 'defaultimg':

matemat/webserver/pagelets/buy.py

@@ -2,7 +2,7 @@ from bottle import get, post, redirect, request
 
 from matemat.db import MatematDatabase
 from matemat.webserver import session
-from matemat.webserver.config import get_app_config
+from matemat.webserver import config as c
 
 
 @get('/buy')
@@ -11,7 +11,7 @@ def buy():
     """
     The purchasing mechanism.  Called by the user clicking an item on the product list.
     """
-    config = get_app_config()
+    config = c.get_app_config()
     session_id: str = session.start()
     # If no user is logged in, redirect to the main page, as a purchase must always be bound to a user
     if not session.has(session_id, 'authenticated_user'):
@@ -27,5 +27,9 @@ def buy():
             product = db.get_product(pid)
             # Create a consumption entry for the (user, product) combination
             db.increment_consumption(user, product)
+            stock_provider = c.get_stock_provider()
+            if stock_provider.needs_update():
+                stock_provider.update_stock(product, -1)
+            c.get_dispenser().dispense(product, 1)
     # Redirect to the main page (where this request should have come from)
     redirect('/')

matemat/webserver/pagelets/main.py

@@ -2,7 +2,7 @@ from bottle import route, redirect
 
 from matemat.db import MatematDatabase
 from matemat.webserver import template, session
-from matemat.webserver.config import get_app_config
+from matemat.webserver.config import get_app_config, get_stock_provider
 
 
 @route('/')
@@ -24,7 +24,7 @@ def main_page():
             products = db.list_products()
             # Prepare a response with a jinja2 template
             return template.render('productlist.html',
-                                   authuser=user, products=products, authlevel=authlevel,
+                                   authuser=user, products=products, authlevel=authlevel, stock=get_stock_provider(),
                                    setupname=config['InstanceName'])
         else:
             # If there are no admin users registered, jump to the admin creation procedure

matemat/webserver/pagelets/modproduct.py

@@ -11,7 +11,7 @@ from matemat.db.primitives import Product
 from matemat.exceptions import DatabaseConsistencyError
 from matemat.util.currency_format import parse_chf
 from matemat.webserver import template, session
-from matemat.webserver.config import get_app_config
+from matemat.webserver.config import get_app_config, get_stock_provider
 
 
 @get('/modproduct')
@@ -86,17 +86,23 @@ def handle_change(args: FormsDict, files: FormsDict, product: Product, db: Matem
     # 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:
+        for key in ['name', 'pricemember', 'pricenonmember']:
-            return
+            if key 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))
+        stockable = 'stockable' in args
         # 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)
+                              name=name, price_member=price_member, price_non_member=price_non_member,
+                              stock=stock, stockable=stockable)
+            stock_provider = get_stock_provider()
+            if stock_provider.needs_update() and product.stockable:
+                stock_provider.set_stock(product, stock)
         except DatabaseConsistencyError:
             return
         # If a new product image was uploaded, process it

package/release.py

@@ -32,7 +32,8 @@ def parse_changelog(tag: str) -> Optional[str]:
 def fetch_job_ids(project_id: int, pipeline_id: int, api_token: str) -> Dict[str, str]:
     url: str = f'https://gitlab.com/api/v4/projects/{project_id}/pipelines/{pipeline_id}/jobs'
     headers: Dict[str, str] = {
-        'Private-Token': api_token
+        'Private-Token': api_token,
+        'User-Agent': 'curl/7.70.0'
     }
     req = urllib.request.Request(url, headers=headers)
     try:
@@ -52,7 +53,10 @@ def fetch_job_ids(project_id: int, pipeline_id: int, api_token: str) -> Dict[str
 
 
 def fetch_single_shafile(url: str) -> str:
-    req = urllib.request.Request(url)
+    headers: Dict[str, str] = {
+      'User-Agent': 'curl/7.70.0'
+    }
+    req = urllib.request.Request(url, headers=headers)
     try:
         resp: http.client.HTTPResponse = urllib.request.urlopen(req)
     except HTTPError as e:
@@ -138,7 +142,8 @@ def main():
         f'https://gitlab.com/api/v4/projects/{project_id}/repository/tags/{release_tag}/release'
     headers: Dict[str, str] = {
         'Private-Token': api_token,
-        'Content-Type': 'application/json; charset=utf-8'
+        'Content-Type': 'application/json; charset=utf-8',
+        'User-Agent': 'curl/7.70.0'
     }
 
     request = urllib.request.Request(

templates/admin_restricted.html

@@ -49,6 +49,9 @@
         <label for="admin-newproduct-price-non-member">Non-member price: </label>
         CHF <input id="admin-newproduct-price-non-member" type="number" step="0.01" name="pricenonmember" value="0" /><br/>
 
+        <label for="admin-newproduct-stockable">Stockable: </label>
+        <input id="admin-newproduct-stockable" type="checkbox" name="stockable" checked="checked" /><br/>
+
         <label for="admin-newproduct-image">Image: </label>
         <input id="admin-newproduct-image" name="image" type="file" accept="image/*" /><br/>
 
@@ -63,7 +66,9 @@
         <label for="admin-restock-productid">Product: </label>
         <select id="admin-restock-productid" name="productid">
             {% for product in products %}
+            {% if product.stockable %}
             <option value="{{ product.id }}">{{ product.name }} ({{ product.stock }})</option>
+            {% endif %}
             {% endfor %}
         </select><br/>
 

templates/modproduct.html

@@ -20,6 +20,9 @@
         <label for="modproduct-price-non-member">Non-member price: </label>
         CHF <input id="modproduct-price-non-member" type="number" step="0.01" name="pricenonmember" value="{{ product.price_non_member|chf(False) }}" /><br/>
 
+        <label for="modproduct-stockable">Stockable: </label>
+        <input id="modproduct-stockable" type="checkbox" name="stockable" {% if product.stockable %} checked="checked" {% endif %} /><br/>
+
         <label for="modproduct-balance">Stock: </label>
         <input id="modproduct-balance" name="stock" type="text" value="{{ product.stock }}" /><br/>
 

templates/productlist.html

@@ -34,7 +34,9 @@
                 </span><br/>
                 <div class="imgcontainer">
                     <img src="/static/upload/thumbnails/products/{{ product.id }}.png" alt="Picture of {{ product.name }}"/>
-                    <span class="thumblist-stock">{{ product.stock }}</span>
+                    {% if product.stockable %}
+                    <span class="thumblist-stock">{{ stock.get_stock(product) }}</span>
+                    {% endif %}
                 </div>
             </a>
         </div>