Jayden+aaron v2 3172025

backend/utils/db.py

@@ -12,103 +12,147 @@
 import os
 import sqlite3
 from models.snack import Snack, SnackCreateSchema, SnackUpdateSchema
+from exceptions import DatabaseError, ConnectionError, RecordNotFoundError, DuplicateRecordError, DatabaseInitError
 
 def get_db_connection(db_file_path:str="data/db.sqlite3"):
     """Creates and returns a SQLite database connection"""
-    connection = sqlite3.connect(db_file_path)
-    connection.row_factory = sqlite3.Row  # Allows accessing columns by name
-    return connection
+    try:
+        connection = sqlite3.connect(db_file_path)
+        connection.row_factory = sqlite3.Row  # Allows accessing columns by name
+        return connection
+    except sqlite3.Error as e:
+        raise DatabaseError(f"Error creating database connection: {str(e)}")
 
 
 def init_db(db_file_path: str = "data/db.sqlite3"):
     """Initialize the database with schema"""
-    os.makedirs(os.path.dirname(db_file_path), exist_ok=True)
-    with open('data/schema.sql') as f:
-        schema = f.read()
-    with get_db_connection() as conn:
-        conn.executescript(schema)
-
+    try:
+        os.makedirs(os.path.dirname(db_file_path), exist_ok=True)
+        with open('data/schema.sql') as f:
+            schema = f.read()
+        with get_db_connection() as conn:
+            conn.executescript(schema)
+    except sqlite3.Error as e:
+        raise DatabaseInitError(f"Error when initializing database: {str(e)}")
+
 
 def get_inventory() -> list[Snack]:
     """Returns all snacks in the database"""
-    with get_db_connection() as conn:
-        cursor = conn.cursor()
-        cursor.execute("SELECT * FROM snacks")
-        records = cursor.fetchall()
-        return [Snack(**record) for record in records]
+    try:
+        with get_db_connection() as conn:
+            cursor = conn.cursor()
+            cursor.execute("SELECT * FROM snacks")
+            records = cursor.fetchall()
+            if not records: 
+                raise RecordNotFoundError("No snacks in database")
+            return [Snack(**record) for record in records]
+    except ConnectionError as e:
+        raise ConnectionError(f"Error when connecting to database: {str(e)}")
+    except sqlite3.Error as e:
+        raise DatabaseError(f"Database error when fetching all snacks: {str(e)}")
 
 
 def get_snack(sku: str) -> Snack:
     """Returns a single snack by SKU"""
-    with get_db_connection() as conn:
-        cursor = conn.cursor()
-        cursor.execute("SELECT * FROM snacks WHERE sku = ?", (sku,))
-        record = cursor.fetchone()
-        return Snack(**record)
-
+    try:
+        with get_db_connection() as conn:
+            cursor = conn.cursor()
+            cursor.execute("SELECT * FROM snacks WHERE sku = ?", (sku,))
+            record = cursor.fetchone()
+            if record is None:
+                raise RecordNotFoundError(f"No snack found with SKU: {sku}")
+            return Snack(**record)
+    except ConnectionError as e:
+        raise ConnectionError(f"Error when connecting to database: {str(e)}")
+    except sqlite3.Error as e:
+        raise DatabaseError(f"Database error when fetching snack {sku}: {str(e)}")
+
 
 def delete_snack(sku: str) -> Snack:
     """Removes a snack from the database"""
-    with get_db_connection() as conn:
-        cursor = conn.cursor()
-        cursor.execute("""
-            DELETE FROM snacks 
-            WHERE sku = ? 
-            RETURNING *
-        """, (sku,))
-        record = cursor.fetchone()
-        return Snack(**record)
-
-
+    try:
+        with get_db_connection() as conn:
+            cursor = conn.cursor()
+            cursor.execute("""
+                DELETE FROM snacks 
+                WHERE sku = ? 
+                RETURNING *
+            """, (sku,))
+            record = cursor.fetchone()
+            if record is None:
+                raise RecordNotFoundError(f"Didn't delete snack {sku} successfully")
+            return Snack(**record)
+    except ConnectionError as e:
+        raise ConnectionError(f"Error when connecting to database: {str(e)}")
+    except sqlite3.Error as e:
+        raise DatabaseError(f"Database error when deleting snack {sku}: {str(e)}")
+
+
 def create_snack(snack: SnackCreateSchema) -> Snack:
     """Creates a new snack in the database"""
-    with get_db_connection() as conn:
-        cursor = conn.cursor()
-        cursor.execute("""
-            INSERT INTO snacks 
-                (sku, name, quantity, price, description, category, photo_url)
-            VALUES 
-                (?, ?, ?, ?, ?, ?, ?)
-            RETURNING *
-        """, (
-            snack.sku, 
-            snack.name, 
-            snack.quantity if snack.quantity is not None else 1, 
-            snack.price, 
-            snack.description, 
-            snack.category, 
-            snack.photo_url
-        ))
-        record = cursor.fetchone()
-        return Snack(**record)
+    try:
+        with get_db_connection() as conn:
+            cursor = conn.cursor()
+            cursor.execute("""
+                INSERT INTO snacks 
+                    (sku, name, quantity, price, description, category, photo_url)
+                VALUES 
+                    (?, ?, ?, ?, ?, ?, ?)
+                RETURNING *
+            """, (
+                snack.sku, 
+                snack.name, 
+                snack.quantity if snack.quantity is not None else 1, 
+                snack.price, 
+                snack.description, 
+                snack.category, 
+                snack.photo_url
+            ))
+            record = cursor.fetchone()
+            if record is None:
+                raise DatabaseError(f"Error when creating snack")
+            return Snack(**record)
+    except DuplicateRecordError as e:
+        raise DuplicateRecordError(f"This snack already exists: {str(e)}")
+    except ConnectionError as e:
+        raise ConnectionError(f"Error when connecting to database: {str(e)}")
+    except sqlite3.Error as e:
+        raise DatabaseError(f"Database error when creating snack {snack.sku}: {str(e)}")
 
 
 def update_snack(sku: str, updates: SnackUpdateSchema) -> Snack:
     """Updates an existing snack in the database"""
-    with get_db_connection() as conn:
-        cursor = conn.cursor()
-        cursor.execute("""
-            UPDATE snacks 
-            SET 
-                name = ?, 
-                quantity = ?, 
-                price = ?, 
-                description = ?, 
-                category = ?, 
-                photo_url = ?       
-            WHERE sku = ?
-            RETURNING *
-        """, (
-            updates.name, 
-            updates.quantity, 
-            updates.price, 
-            updates.description, 
-            updates.category, 
-            updates.photo_url, 
-            sku
-        ))
-        record = cursor.fetchone()
-        return Snack(**record)
+    try:
+        with get_db_connection() as conn:
+            cursor = conn.cursor()
+            cursor.execute("""
+                UPDATE snacks 
+                SET 
+                    name = ?, 
+                    quantity = ?, 
+                    price = ?, 
+                    description = ?, 
+                    category = ?, 
+                    photo_url = ?       
+                WHERE sku = ?
+                RETURNING *
+            """, (
+                updates.name, 
+                updates.quantity, 
+                updates.price, 
+                updates.description, 
+                updates.category, 
+                updates.photo_url, 
+                sku
+            ))
+            record = cursor.fetchone()
+            if record is None:
+                raise RecordNotFoundError(f"Snack with SKU: {sku} doesn't exist")
+            return Snack(**record)
+    except ConnectionError as e:
+        raise ConnectionError(f"Error when connecting to database: {str(e)}")
+    except sqlite3.Error as e:
+        raise DatabaseError(f"Database error when updating snack {sku}: {str(e)}")
 
 
 # Initialize the database and create tables

backend/utils/exceptions.py

@@ -0,0 +1,19 @@
+class DatabaseError(Exception):
+    """Base exception for database errors"""
+    pass
+
+class ConnectionError(DatabaseError):
+    """Failed to connect to database"""
+    pass
+
+class RecordNotFoundError(DatabaseError):
+    """Requested record does not exist"""
+    pass
+
+class DuplicateRecordError(DatabaseError):
+    """Record with this identifier already exists"""
+    pass
+
+class DatabaseInitError(DatabaseError):
+    """Failed to initialize database"""
+    pass