Unpack json in php - php

Question

I am trying to unpack my json object send via http post request in a php controller:
$products = $_POST['products'] ?? '';
foreach($products as $purchase){
$productId =$purchase['productid'];
$qty = $purchase['quantity'];
$params = array(
'form_key' => $this->formKey->getFormKey(),
'product' => $productId,
'qty' => $qty
);
//Load the product based on productID
$_product = $this->product->load($productId);
$this->cart->addProduct($_product, $params);
$this->cart->save();
}
This is the format of my json object being sent, stored in a variable called list.
0: {productid: "2910", quantity: "2"}
1: {productid: "2911", quantity: "1"}
2: {productid: "2913", quantity: "4"}
3: {productid: "2914", quantity: "3"}
This is my post request (content type is also set to application/json):
$.post("http://dev.website.co.uk/batchorder/index/addtocart",
{
products:list,
},
function(data, status){
console.log("Data: " + data);
console.log("Status: " + status);
});
This has always worked for me before so i cannot see where i am going wrong with it.
The error i am getting is Warning: Invalid argument supplied for foreach(). but i am assuming it has something to do with my json object.
EDIT:
$("#AddToCartButton").click(function(){
var list = [];
$("#tabCollection :input").each(function(){
var input = $(this);
if($(this)[0].value > 0){
var myArray = {'productid': $(this)[0].id, 'quantity': $(this)[0].value};
list.push(myArray);
}
});
var JSONStringlist = JSON.stringify(list);
var JSONlist = JSON.parse(JSONStringlist);
console.log(JSONlist);
$.ajaxSetup({
headers:{
'Content-Type': "application/json",
}
});
$.post("http://dev.website.co.uk/batchorder/index/addtocart",
{
"products":JSONlist,
},
function(data, status){
console.log("Data: " + data);
console.log("Status: " + status);
});
});
EDIT 2:
example of JSON String:
[{"productid":"2182","quantity":"1"},{"productid":"2183","quantity":"1"},{"productid":"2184","quantity":"1"},{"productid":"2185","quantity":"1"}]

Answer 1

$products = $_POST['products'] ?? '';
foreach($products as $purchase){
Your $products is either "something that is iterable" or a empty string.
In case it's a array, it's iterable, and the foreach will succesfully execute. But in case it's a empty string, it's going to complain about "Warning: Invalid argument supplied for foreach()", cause a string is not really iterable.
So what you need to do is make sure, that $products is always an array, either an empty or filled with json objects.
If you change:
$products = $_POST['products'] ?? '';
to:
$products = json_decode($_POST['products']) ?? array();
The foreach won't complain, and if $_POST['products'] is empty nothing will be saved in the cart.
In your javascript file change:
$.post("http://dev.website.co.uk/batchorder/index/addtocart",
{
"products":JSONlist,
},
function(data, status){
console.log("Data: " + data);
console.log("Status: " + status);
});
});
to:
$.post("http://dev.website.co.uk/batchorder/index/addtocart",
{
"products":JSONStringlist,
},
function(data, status){
console.log("Data: " + data);
console.log("Status: " + status);
});
});
You are parsing an JavaScript object to JSON, and then you're reparsing it back to an JavaScript object.
PHP does not really understand JavaScript objects, but understands JSON objects.