Laravel 将相同产品的添加到购物车按钮添加到购物车，数量 +1

Posted 2023-03-21

【中文标题】Laravel 将相同产品的添加到购物车按钮添加到购物车，数量 +1

【英文标题】：Laravel add to cart button with same product into cart with +1 quantity

【发布时间】：2021-04-04 15:00:03

【问题描述】：

我是 Laravel 的新手。添加到购物车按钮可将相同的产品添加到购物车中，数量为 +1。 试图检查库存是否大于数量。当一件商品的数量为 3 件而不是 2 件时，我想显示一些文本“请求的数量不可用”而不是表单提交。这可能吗？

总库存有 2 个。

问题是更多的添加到购物车到相同的产品到 +1 数量。没有什么能阻止添加到购物车“请求的数量不可用”。谁能帮帮我。

在控制器中

    public function add_to_cart(Request $request)
        
            $name = $request->product_name;
            $price = $request->product_price;
            $itemno = $request->product_itemno;
            $qty = $request->product_quantity;
            $color = $request->product_color;
            $size = $request->product_size;
    
            $stock = products::join('stocks', 'stocks.pid', 'products.id')
            ->join('sizes', 'sizes.pid', 'products.id')
            ->where([['products.item_no', '=', $itemno],['sizes.size_name', '=', $size]])
            ->first();

            // Current stock quantity
            $stockqty = $stock->qty;
            if($qty <= $stockqty)
            
             echo "<p>was successfully added to your shopping cart</p>";
    
             Cart::add([
                'id' => $itemno,
                'weight' => 500,
                'name' => $name, 
                'price' => $price, 
                'qty' => $qty, 
                'color' => $color, 
                'size' => $size
                ]);
            
            else
            
             echo "<p>The Requested quantity for this product is not available.</p>";
            
            
        

在 Ajax 中

$(document).ready(function()


$(document).on('click','#add_to_cart',function (e) 
    
        var cart_count = $('.navbar-tool-badge').text();
    cart_count = parseInt(cart_count);
    
    if($('input[type=radio][name=size]:checked').length == 0)
      
         $('.msg').html('Please choose size.');
         return false;
       else 
    var product_name = $('#hidden-name').val();
  var product_price = $('#hidden-price').val();
  var product_itemno = $('#itemno').val();
  var product_quantity = $('.quantity').val(); 
  var product_color = $('#color').val();
  var product_size = $("input[name='size']:checked").val();
  
e.preventDefault();
 
$.ajax
(
method:"POST",
url: " route('add_to_cart')",
 data:
  "_token": " csrf_token() ",
   product_name:product_name,
    product_price:product_price,
     product_itemno:product_itemno,
      product_quantity:product_quantity,
       product_color:product_color,
        product_size:product_size,
cache: false,
success: function(response)

$("#getCode").html(response);
$("#myModal").modal('show');

 
);

 );
 
 
);

【问题讨论】：

那么问题出在哪里？您可以将echo 替换为return response()->json(['message' => 'Some message']); 并在前端处理消息以显示给客户

echo 或 response()-> 类似。向 ajax 调用发送数据时最好使用 echo。数量 4 使用会话。总库存 2。我想防止将具有相同产品的购物车添加到购物车中，数量比总库存 2 增加 1。如显示：“请求的数量不可用”。为了获得成功的消息，它应该总是比数量大。开始添加到购物车，数量比总库存 2.like display: 已成功添加到您的购物车

所以您正在检查if($qty <= $stockqty) 对吗？那么什么不起作用

$qty 与当前会话无关。 $qty 获取输入字段编号的值。我想检查如何使数量（当前会话）少于总库存。

您是否存储会话中每个产品的当前购物车数量？如果是这样，您可以通过密钥从会话中获取值。如果没有，您可以在进行 ajax 调用时将购物车信息传回 add_to_cart 函数

【参考方案1】：

无论何时执行add_to_cart，您都可以将添加到购物车的每个产品数量的值放入会话中。像下面这样的东西应该可以工作。

public function add_to_cart(Request $request)

    //You should get only the id of the product and cart from the frontend
    //via ajax request
    //Then you should fetch the Product record from database for that id
    $product = Product::findOrFail($request->pid);
    $cart = Cart::findOrFail($request->cid);
    $sessionKey = "Cart-$cart->id-$product->id";
    $session = $request->session();
    $requestedQty = $request->product_quantity;
    $desiredQty = 0;
     
    //Get the stock data
    $stock = products::join('stocks', 'stocks.pid', 'products.id')
        ->join('sizes', 'sizes.pid', 'products.id')
        ->where([
            ['products.item_no', '=', $itemno],
            ['sizes.size_name', '=', $size]
        ])
        ->first();
    
    // Current stock quantity
    $stockqty = $stock->qty;

    //If the requested quantity is greater than the available stock
    //when the product is added for the first time, send out of stock    
    if($requestedQty > $stockqty) 
        echo "<p>The Requested quantity for this product is not available.</p>";
    

    //When a product is added for the first time session won't have entry
    if(empty($session->get($sessionKey)) 
        $desiredQty = $requestedQty;       
        $session->put($sessionKey, $requestedQuantity);
     else 
        $desiredQty = $session->get($sessionKey) + $requestedQty;
    

    if($desiredQty > $stockqty) 
        echo "<p>The Requested quantity for this product is not available.</p>";
    

    //Overwrite the session entry with the new quantity
    $session->put($sessionKey, $desiredQty);
   
    echo "<p>was successfully added to your shopping cart</p>";
    
    Cart::add([
        'id' => $itemno,
        'weight' => 500,
        'name' => $name, 
        'price' => $price, 
        'qty' => $requestedQty, 
        'color' => $color, 
        'size' => $size
    ]);