Business Logic Errors

  package main
  
  import (
      "net/http"
      "strconv"
  )
  
  func checkoutHandler(w http.ResponseWriter, r *http.Request) {
-     total, _ := strconv.ParseFloat(r.FormValue("total"), 64)
+     productID := r.FormValue("product_id")
+     qty, err := strconv.Atoi(r.FormValue("quantity"))
+     if err != nil || qty <= 0 {
+         http.Error(w, "Invalid quantity", http.StatusBadRequest)
+         return
+     }
+ 
+     var product Product
+     if err := db.First(&product, productID).Error; err != nil {
+         http.Error(w, "Product not found", http.StatusNotFound)
+         return
+     }
+ 
+     total := product.Price * float64(qty)
      processPayment(total)
      w.Write([]byte("Payment processed"))
  }
  

  app.post('/checkout', async (req, res) => {
-   const { total } = req.body;
+   const product = await Product.findById(req.body.productId);
+   const total = product.price * req.body.quantity;
    await stripe.charges.create({ amount: total, currency: 'usd' });
  });
  

  from flask import request
  
  @app.route('/checkout', methods=['POST'])
  def checkout():
-     price = float(request.form['price'])
-     quantity = int(request.form['quantity'])
-     stripe.Charge.create(amount=int(price * quantity * 100))
+     item_id = int(request.form['item_id'])
+     quantity = int(request.form['quantity'])
+     product = Product.query.get(item_id)
+     total = product.price * quantity
+     stripe.Charge.create(amount=int(total * 100))