How to create a search that uses barcode - ajax

Question

I'm creating a search system for a point of sale that uses barcodes to search for products. When a user scans a barcode, the product with the corresponding barcode gets added to the cart. I pass the barcode to the controller using Ajax. The problem is, the resulting query is running twice doubling the order quantity when the product gets added to the cart. I don't know why this is happening.
View/Search Bar
<div class="frmSearch">
<input type="text" id="search" name="search" class="form-control" placeholder="Type Product Name..."
onmouseover="this.focus();"/>
</div>
<script type="text/javascript">
$('#search').on('keyup', function () {
$value = $(this).val();
$.ajax({
type: 'get',
url: '{{URL::to('search')}}',
data: {'search': $value},
success: function (data) {
window.location.href = "/addsale/" + data;
}
});
});
</script>
Controller
public function search(Request $request)
{
if ($request->ajax()) {
$raws = DB::table('items_masters')->where('bcode', '=', $request->search)->first();
if ($raws) {
$output = $product->id;
}
return Response($output);
}
}
Method to add a product to the cart
public function add($id)
{
$userid = Auth::user()->id;
$shop = Auth::user()->shop_id;
$product_id = $id;
$tdo = item_quantity::getQuery('item_quantities')->where([
['shop_id', '=', $shop],
['item_id', '=', $product_id]
])->get();
foreach ($tdo as $key => $tad) {
$product_quantity = $tad->quantity;
}
if (empty($product_quantity)) {
session()->flash('message', 'Item Not In Your Shop');
return redirect('/sales_area');
} elseif ($product_quantity <= 0) {
session()->flash('message', 'Item Out Of Stock');
return redirect('/sales_area');
} else {
$todo = tblcart::getQuery('tblcarts')->where([
['product_id', '=', $id], ['shop_id', '=', $shop],
['member_id', '=', $uid]
])->get();
foreach ($todo as $key => $tada) {
$cart_id = $tada->id;
}
if (empty($cart_id)) {
$tem = new tblcart;
$tem->product_id = $product_id;
$tem->quantity = 1;
$tem->shop_id = $shop;
$tem->member_id = $userid;
$tem->save();
return redirect('/sales_area');
} else {
$tem = tblcart::find($cid);
$tem->quantity = $tem->quantity + 1;
$tem->save();
return redirect('/sales_area');
}
}
}
Currently, when a user adds a product to the cart, the order quantity is doubled, so instead of one, he gets two. If the user adds the same product again, he gets four instead of two. How can I sort this out?

Answer 1

Looks like perhaps a timing problem, depending on if the add method is called directly from the search. With keyup, you run a possible risk of triggering the search function at least once, and possibly more than once based on the user still typing the product they want even after the original ajax request has been sent based on the previous character typed within the search bar.
Suggestion would be to add a time delay on either the keyup function, or within your search code. Say something like (pseudo code) within the controller
if($timeOfLastTransaction < 30 seconds && $productId == $previousProductId)
// cancel this duplicate
else
set $timeOfLastTransaction
set $previousProductId
I'm still not sure what's calling the add() method, and this would be a good start for bug hunting the specific doubling-up error.
But, looking at that code in the add() method, there are a number of things that you might clean slightly -- and may resolve your issue. Suggest naming the $id variable $product_id directly in the method's params instead of renaming it in the top part -- you use two different vars for the same thing in multiple places, and it is a little confusing.
A little bigger issue is that you are potentially re-assigning the same variable in several places after pulling a collection from the database:
$tdo = item_quantity::getQuery('item_quantities')->where( [['shop_id', '=', $shop],
['item_id', '=', $product_id]])->get();
foreach ($tdo as $key => $tad) {
$product_quantity=$tad->quantity;
}
This line and the next DB pull below it both loop through a collection and re-assign / overwrite $product_quantity in this case and $cart_id in the next. Why not use ->first() and skip the loop? I think this might reduce any unforeseen errors as well