add pydantic on backend

backend/app/routes/api.py

@@ -1,10 +1,13 @@
 import time
+from decimal import Decimal
+from pydantic import ValidationError
 
 from flask import Blueprint, request, jsonify
 from flask_jwt_extended import jwt_required, get_jwt_identity, create_access_token, create_refresh_token
 from app import db
 from app.models import User, Product, OrderItem, Order
 from app.celery import celery
+from app.schemas import ProductCreateRequest, ProductResponse
 
 api_bp = Blueprint("api", __name__)
 
@@ -104,21 +107,28 @@ def create_product():
     if not user or not user.is_admin:
         return jsonify({"error": "Admin access required"}), 403
     
-    data = request.get_json()
-    
-    product = Product(
-        name=data["name"],
-        description=data.get("description"),
-        price=data["price"],
-        stock=data.get("stock", 0),
-        image_url=data.get("image_url"),
-        category=data.get("category")
-    )
-    
-    db.session.add(product)
-    db.session.commit()
-    
-    return jsonify(product.to_dict()), 201
+    try:
+        # Validate request data using Pydantic schema
+        product_data = ProductCreateRequest(**request.get_json())
+        
+        product = Product(
+            name=product_data.name,
+            description=product_data.description,
+            price=product_data.price,
+            stock=product_data.stock,
+            image_url=product_data.image_url,
+            category=product_data.category
+        )
+        
+        db.session.add(product)
+        db.session.commit()
+        
+        # Use Pydantic schema for response
+        response = ProductResponse.model_validate(product)
+        return jsonify(response.model_dump()), 201
+        
+    except ValidationError as e:
+        return jsonify({"error": "Validation error", "details": e.errors()}), 400
 
 
 @api_bp.route("/products/<int:product_id>", methods=["PUT"])

backend/app/schemas/__init__.py

@@ -0,0 +1,4 @@
+"""Pydantic schemas for request/response validation"""
+from app.schemas.product import ProductCreateRequest, ProductResponse
+
+__all__ = ["ProductCreateRequest", "ProductResponse"]

backend/app/schemas/product.py

@@ -0,0 +1,64 @@
+"""Pydantic schemas for Product model"""
+from pydantic import BaseModel, Field, field_validator
+from decimal import Decimal
+from datetime import datetime
+from typing import Optional
+
+
+class ProductCreateRequest(BaseModel):
+    """Schema for creating a new product"""
+    name: str = Field(..., min_length=1, max_length=200, description="Product name")
+    description: Optional[str] = Field(None, description="Product description")
+    price: Decimal = Field(..., gt=0, description="Product price (must be greater than 0)")
+    stock: int = Field(default=0, ge=0, description="Product stock quantity")
+    image_url: Optional[str] = Field(None, max_length=500, description="Product image URL")
+    category: Optional[str] = Field(None, description="Product category")
+    
+    class Config:
+        json_schema_extra = {
+            "example": {
+                "name": "Handcrafted Wooden Bowl",
+                "description": "A beautiful handcrafted bowl made from oak",
+                "price": 45.99,
+                "stock": 10,
+                "image_url": "https://example.com/bowl.jpg",
+                "category": "Woodwork"
+            }
+        }
+    
+    @field_validator("price")
+    @classmethod
+    def validate_price(cls, v: Decimal) -> Decimal:
+        """Validate that price has at most 2 decimal places"""
+        if v.as_tuple().exponent < -2:
+            raise ValueError("Price must have at most 2 decimal places")
+        return v
+
+
+class ProductResponse(BaseModel):
+    """Schema for product response"""
+    id: int
+    name: str
+    description: Optional[str] = None
+    price: float
+    stock: int
+    image_url: Optional[str] = None
+    is_active: bool
+    created_at: Optional[datetime] = None
+    updated_at: Optional[datetime] = None
+    
+    class Config:
+        from_attributes = True
+        json_schema_extra = {
+            "example": {
+                "id": 1,
+                "name": "Handcrafted Wooden Bowl",
+                "description": "A beautiful handcrafted bowl made from oak",
+                "price": 45.99,
+                "stock": 10,
+                "image_url": "https://example.com/bowl.jpg",
+                "is_active": True,
+                "created_at": "2024-01-15T10:30:00",
+                "updated_at": "2024-01-15T10:30:00"
+            }
+        }

backend/requirements/base.txt

@@ -8,3 +8,4 @@ python-dotenv==1.0.0
 Werkzeug==3.0.1
 SQLAlchemy==2.0.23
 celery[redis]==5.3.6
+pydantic==2.5.3