Changes:

add Readme per layer
move db calls to interface_adapters
implement product example
add tests
add __init__ files for easier to read imports

.gitignore

@@ -2,3 +2,5 @@
 __pycache__/
 *.py[cod]
 *$py.class
+
+/env

src/entities/README.md

@@ -0,0 +1,11 @@
+# ENTITIES
+Entities encapsulate enterprise-wide Critical Business Rules. An entity can be an
+object with methods, or it can be a set of data structures and functions. It doesn’t
+matter so long as the entities can be used by many different applications in the
+enterprise.
+If you don’t have an enterprise and are writing just a single application, then these
+entities are the business objects of the application. They encapsulate the most general
+and high-level rules. They are the least likely to change when something external
+changes. For example, you would not expect these objects to be affected by a change
+to page navigation or security. No operational change to any particular application
+should affect the entity layer.

src/entities/__init__.py

@@ -0,0 +1,11 @@
+import importlib
+import pkgutil
+import inspect
+
+__all__ = []
+for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
+    module = importlib.import_module(f".{module_name}", __name__)
+    for name, obj in inspect.getmembers(module, inspect.isclass):
+        if obj.__module__ == module.__name__:
+            globals()[name] = obj
+            __all__.append(name)

src/entities/cart.py

@@ -3,8 +3,8 @@ from typing import List
 from dataclasses import dataclass
 
 #dependency imports
-from entities.cart_item import CartItem
-from entities.product import Product
+from .cart_item import CartItem
+from .product import Product
 
 @dataclass
 class Cart:

src/framework_driver/README.md

@@ -0,0 +1,8 @@
+# FRAMEWORKS AND DRIVERS
+The outermost layer of the model in Figure 22.1 is generally composed of
+frameworks and tools such as the database and the web framework. Generally you
+don’t write much code in this layer, other than glue code that communicates to the
+next circle inward.
+The frameworks and drivers layer is where all the details go. The web is a detail. The
+database is a detail. We keep these things on the outside where they can do little
+harm.

src/interface_adapters/README.md

@@ -0,0 +1,17 @@
+# INTERFACE ADAPTERS
+The software in the interface adapters layer is a set of adapters that convert data from
+the format most convenient for the use cases and entities, to the format most
+convenient for some external agency such as the database or the web. It is this layer,
+for example, that will wholly contain the MVC architecture of a GUI. The
+presenters, views, and controllers all belong in the interface adapters layer. The
+models are likely just data structures that are passed from the controllers to the use
+cases, and then back from the use cases to the presenters and views.
+Similarly, data is converted, in this layer, from the form most convenient for entities
+and use cases, to the form most convenient for whatever persistence framework is
+being used (i.e., the database). No code inward of this circle should know anything at
+all about the database. If the database is a SQL database, then all SQL should be
+restricted to this layer—and in particular to the parts of this layer that have to do with
+the database.
+Also in this layer is any other adapter necessary to convert data from some external
+form, such as an external service, to the internal form used by the use cases and
+entities.

src/interface_adapters/controllers/__init__.py

@@ -0,0 +1,11 @@
+import importlib
+import pkgutil
+import inspect
+
+__all__ = []
+for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
+    module = importlib.import_module(f".{module_name}", __name__)
+    for name, obj in inspect.getmembers(module, inspect.isclass):
+        if obj.__module__ == module.__name__:
+            globals()[name] = obj
+            __all__.append(name)

src/interface_adapters/controllers/cart_controller.py

@@ -8,21 +8,16 @@ from fastapi.templating import Jinja2Templates
 import httpx
 
 #dependency imports
-from use_cases.view_cart import ViewCart
-from interface_adapters.dtos.view_cart_response import ViewCartResponseDTO, CartItemDTO
-from interface_adapters.dtos.view_cart_request import ViewCartRequestDTO
-from interface_adapters.repositories.cart_repository import CartRepository
-
-#from interface_adapters.mocks.cart_db import CartDatabase
-from framework_driver.db.db_cart import CartDatabase
+from use_cases import ViewCart
+from interface_adapters.dtos import ViewCartRequestDTO, ViewCartResponseDTO, CartItemDTO
+from interface_adapters.repositories import SQLCartRepository
 
 # Set up templates
 templates = Jinja2Templates(directory="framework_driver/ui/templates")
 
 # Initialize components
-cart_database = CartDatabase()  # Concrete database implementation
-cart_repository = CartRepository(cart_database)  # Repository depends on gateway
-view_cart_use_case = ViewCart(cart_repository)  # Use case depends on repository
+cart_repository = SQLCartRepository()
+view_cart_use_case = ViewCart(cart_repository)
 
 router = APIRouter()
 
@@ -35,7 +30,7 @@ async def view_cart(request_dto: ViewCartRequestDTO):
         raise HTTPException(status_code=404, detail="Cart not found")
 
     response_dto = ViewCartResponseDTO(
-        items=[CartItemDTO(product_id=item.product_id, quantity=item.quantity, price=item.price) for item in cart.items],
+        items=[CartItemDTO(product_id=item.product_id, name=item.name, quantity=item.quantity, price=item.price) for item in cart.items],
         total_price=sum(item.price * item.quantity for item in cart.items)
     )
     

src/interface_adapters/controllers/product_controller.py

@@ -0,0 +1,33 @@
+#python imports
+from fastapi import APIRouter, HTTPException
+from fastapi.responses import JSONResponse
+from fastapi import FastAPI, Request
+from fastapi.responses import HTMLResponse
+from fastapi.templating import Jinja2Templates
+
+import httpx
+
+#dependency imports
+from use_cases import ViewProduct
+from interface_adapters.dtos import ViewProductRequestDTO, ViewProductResponseDTO, ProductDTO
+from interface_adapters.repositories import SQLProductRepository
+
+# Initialize components
+product_repository = SQLProductRepository()
+view_product_use_case = ViewProduct(product_repository)
+
+router = APIRouter()
+
+@router.post("/view_product", response_model=ViewProductResponseDTO)
+async def view_product(request_dto: ViewProductRequestDTO):
+
+    product = view_product_use_case.execute(request_dto.product_id)
+
+    if not product:
+        raise HTTPException(status_code=404, detail="Product not found")
+
+    response_dto = ViewProductResponseDTO(
+        product=ProductDTO(id=product.id, name=product.name, description=product.description, price=product.price)
+    )
+    
+    return response_dto

src/interface_adapters/dtos/__init__.py

@@ -0,0 +1,11 @@
+import importlib
+import pkgutil
+import inspect
+
+__all__ = []
+for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
+    module = importlib.import_module(f".{module_name}", __name__)
+    for name, obj in inspect.getmembers(module, inspect.isclass):
+        if obj.__module__ == module.__name__:
+            globals()[name] = obj
+            __all__.append(name)

src/interface_adapters/dtos/view_cart_response.py

@@ -4,6 +4,7 @@ from typing import List, Optional
 
 class CartItemDTO(BaseModel):
     product_id: int
+    name: str
     quantity: int
     price: float
 

src/interface_adapters/dtos/view_product_request.py

@@ -0,0 +1,6 @@
+#python imports
+from pydantic import BaseModel
+from typing import List, Optional
+
+class ViewProductRequestDTO(BaseModel):
+    product_id: int

src/interface_adapters/dtos/view_product_response.py

@@ -0,0 +1,12 @@
+#python imports
+from pydantic import BaseModel
+from typing import List, Optional
+
+class ProductDTO(BaseModel):
+    id: int
+    name: str
+    description: str
+    price: float
+
+class ViewProductResponseDTO(BaseModel):
+    product: ProductDTO

src/interface_adapters/repositories/__init__.py

@@ -0,0 +1,11 @@
+import importlib
+import pkgutil
+import inspect
+
+__all__ = []
+for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
+    module = importlib.import_module(f".{module_name}", __name__)
+    for name, obj in inspect.getmembers(module, inspect.isclass):
+        if obj.__module__ == module.__name__:
+            globals()[name] = obj
+            __all__.append(name)

src/interface_adapters/repositories/cart_database_interface.py

@@ -1,9 +0,0 @@
-#python imports
-from typing import Optional, List
-
-class CartDatabaseInterface:
-    def fetch_cart_items(self, user_id: int) -> Optional[List[dict]]:
-        """
-        Abstract method to fetch cart items from the database for a given user ID.
-        """
-        raise NotImplementedError("fetch_cart_items must be implemented by a subclass")

src/interface_adapters/repositories/cart_repository.py

@@ -1,13 +0,0 @@
-#python imports
-from typing import Optional, List
-
-#dependency imports
-from use_cases.cart_repository_interface import CartRepositoryInterface
-from interface_adapters.repositories.cart_database_interface import CartDatabaseInterface
-
-class CartRepository(CartRepositoryInterface):
-    def __init__(self, database_gateway: CartDatabaseInterface):
-        self.database_gateway = database_gateway
-
-    def fetch_cart_by_user_id(self, user_id: int) -> Optional[List[dict]]:
-        return self.database_gateway.fetch_cart_items(user_id)

src/interface_adapters/repositories/sql_cart_repository.py

@@ -1,8 +1,11 @@
-import sqlite3
+#python imports
 from typing import Optional, List
-from interface_adapters.repositories.cart_database_interface import CartDatabaseInterface
+import sqlite3
 
-class CartDatabase(CartDatabaseInterface):
+#dependency imports
+from use_cases import ICartRepository
+
+class SQLCartRepository(ICartRepository):
     def __init__(self, db_file="framework_driver/db/shop.db"):
         """Initialize the CartDatabase with a connection to the SQLite database."""
         self.conn = sqlite3.connect(db_file)
@@ -18,7 +21,7 @@ class CartDatabase(CartDatabaseInterface):
         except sqlite3.Error as e:
             print(e)
 
-    def fetch_cart_items(self, user_id: int) -> Optional[List[dict]]:
+    def get_cart_by_user_id(self, user_id: int) -> Optional[List[dict]]:
         """Fetch cart items from the database for a given user ID."""
         sql = "SELECT product_id, name, quantity, price FROM cart WHERE user_id = ?"
         try:

src/interface_adapters/repositories/sql_product_repository.py

@@ -1,7 +1,12 @@
+#python imports
+from typing import Optional, List
 import sqlite3
 
-class ProductDatabase:
-    def __init__(self, db_file):
+#dependency imports
+from use_cases import IProductRepository
+
+class SQLProductRepository(IProductRepository):    
+    def __init__(self, db_file="framework_driver/db/shop.db"):
         """Initialize the ProductDatabase with a connection to the SQLite database."""
         self.conn = sqlite3.connect(db_file)
 
@@ -22,7 +27,8 @@ class ProductDatabase:
         try:
             c = self.conn.cursor()
             c.execute(sql, (product_id,))
-            return c.fetchone()
+            r = c.fetchone()
+            return {'id':r[0], 'name':str(r[1]), 'description':str(r[2]), 'price':r[3]}
         except sqlite3.Error as e:
             print(e)
             return None

src/interface_adapters/repositories/sql_user_repository.py

@@ -1,7 +1,12 @@
+#python imports
+from typing import Optional, List
 import sqlite3
 
-class UserDatabase:
-    def __init__(self, db_file):
+#dependency imports
+from use_cases import IUserRepository
+
+class SQLUserRepository(IUserRepository):
+    def __init__(self, db_file="framework_driver/db/shop.db"):
         """Initialize the UserDatabase with a connection to the SQLite database."""
         self.conn = sqlite3.connect(db_file)
 

src/main.py

@@ -1,4 +1,5 @@
 from interface_adapters.controllers.cart_controller import router as cart_router
+from interface_adapters.controllers.product_controller import router as product_router
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.staticfiles import StaticFiles
 from fastapi.templating import Jinja2Templates
@@ -14,6 +15,7 @@ import os
 
 app = FastAPI()
 app.include_router(cart_router)
+app.include_router(product_router)
 
 # Allow CORS for all origins (for simplicity)
 app.add_middleware(

src/tests/README.md

@@ -0,0 +1,2 @@
+# Tests
+To run tests: python -m unittest discover

src/tests/mocks/__init__.py

@@ -0,0 +1,11 @@
+import importlib
+import pkgutil
+import inspect
+
+__all__ = []
+for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
+    module = importlib.import_module(f".{module_name}", __name__)
+    for name, obj in inspect.getmembers(module, inspect.isclass):
+        if obj.__module__ == module.__name__:
+            globals()[name] = obj
+            __all__.append(name)

src/tests/mocks/cart_db.py

@@ -2,9 +2,9 @@
 from typing import Optional, List
 
 #dependency imports
-from interface_adapters.repositories.cart_database_interface import CartDatabaseInterface
+from use_cases import ICartRepository
 
-class CartDatabase(CartDatabaseInterface):
+class CartDatabase(ICartRepository):
     def __init__(self):
         # Mock database setup
         self.mock_db = {
@@ -17,5 +17,5 @@ class CartDatabase(CartDatabaseInterface):
             ],
         }
 
-    def fetch_cart_items(self, user_id: int) -> Optional[List[dict]]:
+    def get_cart_by_user_id(self, user_id: int) -> Optional[List[dict]]:
         return self.mock_db.get(user_id)

src/tests/mocks/product_db.py

@@ -0,0 +1,16 @@
+#python imports
+from typing import Optional, List
+
+#dependency imports
+from use_cases import IProductRepository
+
+class ProductDatabase(IProductRepository):
+    def __init__(self):
+        # Mock database setup
+        self.mock_db = {
+            1: {"id": 1, "name": "Apple", "description": "gsdg", "price": 0.5},
+            2: {"id": 2, "name": "Bread", "description": "sfg", "price": 2.0},
+        }
+
+    def get_product_by_id(self, product_id: int) -> Optional[List[dict]]:
+        return self.mock_db.get(product_id)

src/tests/use_cases/test_view_cart.py

@@ -0,0 +1,19 @@
+from use_cases import ViewCart
+from tests.mocks import CartDatabase
+import unittest
+
+
+class TestViewCart(unittest.TestCase):
+    def setUp(self):
+        self.cart_database = CartDatabase()
+        self.view_cart_use_case = ViewCart(self.cart_database)
+
+    def test_view_cart_valid_id(self):
+        result = self.view_cart_use_case.execute(1)
+        self.assertIsNotNone(result)
+        #self.assertEqual(result['id'], 1)
+
+
+
+if __name__ == "__main__":
+    unittest.main()

src/tests/use_cases/test_view_product.py

@@ -0,0 +1,19 @@
+from use_cases import ViewProduct
+from tests.mocks import ProductDatabase
+import unittest
+
+
+class TestViewProduct(unittest.TestCase):
+    def setUp(self):
+        self.product_database = ProductDatabase()
+        self.view_product_use_case = ViewProduct(self.product_database)
+
+    def test_view_product_valid_id(self):
+        result = self.view_product_use_case.execute(1)
+        self.assertIsNotNone(result)
+        #self.assertEqual(result['id'], 1)
+
+
+
+if __name__ == "__main__":
+    unittest.main()

src/use_cases/README.md

@@ -0,0 +1,11 @@
+# USE CASES
+The software in the use cases layer contains application-specific business rules. It
+encapsulates and implements all of the use cases of the system. These use cases
+orchestrate the flow of data to and from the entities, and direct those entities to use
+their Critical Business Rules to achieve the goals of the use case.
+We do not expect changes in this layer to affect the entities. We also do not expect
+this layer to be affected by changes to externalities such as the database, the UI, or
+any of the common frameworks. The use cases layer is isolated from such concerns.
+We do, however, expect that changes to the operation of the application will affect
+the use cases and, therefore, the software in this layer. If the details of a use case
+change, then some code in this layer will certainly be affected.

src/use_cases/__init__.py

@@ -0,0 +1,11 @@
+import importlib
+import pkgutil
+import inspect
+
+__all__ = []
+for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
+    module = importlib.import_module(f".{module_name}", __name__)
+    for name, obj in inspect.getmembers(module, inspect.isclass):
+        if obj.__module__ == module.__name__:
+            globals()[name] = obj
+            __all__.append(name)

src/use_cases/cart_repository.py

@@ -0,0 +1,8 @@
+from typing import Optional, List
+
+class ICartRepository:
+    def get_cart_by_user_id(self, user_id: int) -> Optional[List[dict]]:
+        """
+        Abstract method to fetch cart data by user ID.
+        """
+        raise NotImplementedError("get_cart_by_user_id must be implemented by a subclass")

src/use_cases/cart_repository_interface.py

@@ -1,8 +0,0 @@
-from typing import Optional, List
-
-class CartRepositoryInterface:
-    def fetch_cart_by_user_id(self, user_id: int) -> Optional[List[dict]]:
-        """
-        Abstract method to fetch cart data by user ID.
-        """
-        raise NotImplementedError("fetch_cart_by_user_id must be implemented by a subclass")

src/use_cases/product_repository.py

@@ -0,0 +1,8 @@
+from typing import Optional, List
+
+class IProductRepository:
+    def get_product_by_id(self, product_id: int):
+        """
+        Abstract method to fetch product data by user ID.
+        """
+        raise NotImplementedError("get_product_by_id must be implemented by a subclass")

src/use_cases/user_repository.py

@@ -0,0 +1,8 @@
+from typing import Optional, List
+
+class IUserRepository:
+    def get_user_by_id(self, user_id: int):
+        """
+        Abstract method to fetch user data by user ID.
+        """
+        raise NotImplementedError("get_user_by_id must be implemented by a subclass")

src/use_cases/view_cart.py

@@ -2,18 +2,18 @@
 from typing import Optional
 
 #dependency imports
-from entities.cart import Cart, CartItem
-from use_cases.cart_repository_interface import CartRepositoryInterface
+from entities import Cart, CartItem
+from .cart_repository import ICartRepository
 
 class ViewCart:
-    def __init__(self, cart_repository: CartRepositoryInterface):
+    def __init__(self, cart_repository: ICartRepository):
         self.cart_repository = cart_repository
 
     def execute(self, user_id: int) -> Optional[Cart]:
         """
         Fetches the cart data from the repository, converts it to Cart entity.
         """
-        cart_data = self.cart_repository.fetch_cart_by_user_id(user_id)
+        cart_data = self.cart_repository.get_cart_by_user_id(user_id)
         if not cart_data:
             return None
 

src/use_cases/view_product.py

@@ -0,0 +1,19 @@
+#python imports
+from typing import Optional
+
+#dependency imports
+from entities import Product
+from .product_repository import IProductRepository
+
+class ViewProduct:
+    def __init__(self, product_repository: IProductRepository):
+        self.product_repository = product_repository
+
+    def execute(self, product_id: int) -> Optional[Product]:
+        """
+        Fetches the product data from the repository, converts it to Product entity.
+        """
+        product_data = self.product_repository.get_product_by_id(product_id)
+        if not product_data:
+            return None
+        return Product(**product_data)