Iterate over KEYLESS JSON array? - php

Question

I'm building a shopping cart and using a cookie to store the cart contents in a JSON object.
On each page, using Javascript, I need to retrieve the cookie, parse the JSON and iterate over each row, to display the described product in the basket summary.
I decided not to use keys in the array, since if I have a record of the designation of each position, why do I need to store it in the cookie. I thought that was a smart idea, but now all my searching turns up are suggestions to use the keys.
This is a sample of the JSON:
{
"9999.9999":["CentOS6",2,"0.5",150,"23.90"],
"0002.0004":["Support5","","3",5,"12.99"],
"9999.9999":["UbuntuServer12.04LTS",1,"1",220,"42.60"]
}
I was expecting to be able to access the 'price' for example (which is in the last field of each row) of the 2nd record, like so:
basket = JSON.parse(basket);
price = basket[1][4];
That doesn't seem to work.
There are really two parts to this question.
How to cherry pick a value directly from the basket?
How to iterate through it, allowing me to operate on each row in turn?
In case you're wondering about the first field. That is the SKU of the product. The reason there are two "9999.9999" is because that is a reserved number, indicating that the product was a 'custom' product (doesn't refer directly to a catalogue item).
UPDATE
Based on #Samer's answer below, I have updated the code to use arrays, as follows:
The JSON now looks like this:
[
["9999.9999","CentOS6",2,"0.5",150,"23.90"],
["0002.0004","Support5","","3",5,"12.99"],
["9999.9999","UbuntuServer12.04LTS",1,"1",220,"42.60"]
]
I'm now attempting to access it from the cookie as follows:
var basket = readCookie('basket');
basket = JSON.parse(basket);
alert( 'Price of item 2 =' + basket[1][5] );
Only, instead of alerting, 'Price of item 2 = 12.99' I get 'Price of item 2 = undefined'.
I'm wondering what I've done wrong?
UPDATE 2
Still having trouble with this. Maybe I should explain how we're getting the data into the cookie.
The array on the cookie can be updated on the server using PHP (when adding custom items) or client-side using Javascript when a catalogue item is added.
Currently, I'm concentrating on items added server side. I'm using the following code to add the cookie:
<?
extract($_POST, EXTR_SKIP);
// Get contents of existing basket (if any) minus last ']'
// so that it's ready to be added to.
if (isset($_COOKIE['basket'])) {
$basket = json_decode($_COOKIE['basket']);
$chars = strlen($basket)-1;
//echo "<pre>".var_dump($basket)."</pre>";
$cookieVal = substr($basket, 0, $chars);
$cookieVal .= ",
[\"9999.9999\",\"$sltOS\",$vcpuPoints,\"".$ramPoints."\",$storagePoints,\"".$baseServerCostMonthUSD."\"]]";
$cookieVal = json_encode($cookieVal);
/*
* Sample format
*
[["9999.9999","CentOS6",2,"0.5",150,"23.90"],
["0002.0004","Support5","","3",5,"12.99"],
["9999.9999","UbuntuServer12.04LTS",1,"1",220,"42.60"]]
*
*/
} else {
$cookieVal = json_encode("[[\"9999.9999\",\"$sltOS\",$vcpuPoints,\"".$ramPoints."\",$storagePoints,\"".$baseServerCostMonthUSD."\"]]");
}
$exp = time()+3600; // sets expiry to 1 hour;
setcookie ( 'basket' , $cookieVal, $exp, '/' );
Then client-side for reading the cookie, I have this, which is called when the page is loaded:
function initBasket() {
var basket = readCookie('basket');
if (isJSON(basket)) {
// We'll populate the basket
basket = JSON.parse(basket);
alert(basket[1][5]);
} else {
$('#sList').html('Your basket is empty.');
return;
}
}
UPDATE 3
Finally got it working. Thanks for your help.
Maybe the code can help others, so I've included the final code below:
The PHP:
if (isset($_COOKIE['basket'])) {
$cookieVal = json_decode($_COOKIE['basket']);
$cookieVal[] = array
(
"9999.9999",
$sltOS,
$vcpuPoints,
$ramPoints,
$storagePoints,
$baseServerCostMonthUSD
);
$cookieVal = json_encode($cookieVal);
} else {
$cookieArr[] = array
(
"9999.9999",
$sltOS,
$vcpuPoints,
$ramPoints,
$storagePoints,
$baseServerCostMonthUSD
);
$cookieVal = json_encode($cookieArr);
}
// Save VPS choice in basket cookie
$exp = time()+3600; // sets expiry to 1 hour;
setcookie ( 'basket' , $cookieVal, $exp, '/' );
The Javascript:
function initBasket() {
var basket = readCookie('basket');
if (isJSON(basket)) {
// We'll populate the basket
basket = JSON.parse(basket);
alert(basket[1][5]);
} else {
$('#sList').html('Your basket is empty.');
return;
}
}

Answer 1

If the JSON has no keys then it's an array, simply build your data using an array instead of key/value pairs.
var data = [
['CentOS', ''],
['Another Product', ...],
];
UPDATE:
So now based on your new answer, it looks like you're trying to JSON.parse the actual array. JSON.parse usually takes in a string value which has the array and then parses it into an actual array.
To see what I mean take your data array and run it through JSON.stringify and you will see the output, that same output you can then run it through JSON.parse

Answer 2

The problem is in PHP: You json_encode your array twice.
Here you manually encoded it once:
$cookieVal .= ",
[\"9999.9999\",\"$sltOS\",$vcpuPoints,\"".$ramPoints."\",$storagePoints,\"".$baseServerCostMonthUSD."\"]]";
Then here, you do it again:
$cookieVal = json_encode($cookieVal);
So as a result you get a string when you parse json it in javascript.
Obviously, second basket[1][4] gives you an undefined value, since basket is a string and basket[1] is a character.
It helps to use firebug or other debugging utility to take a look what data you get at every step.
So. Simply build an array of arrays in PHP and then json_encode it (once) and your js should work.

Answer 3

{
"9999.9999":["CentOS6",2,"0.5",150,"23.90"],
"0002.0004":["Support5","","3",5,"12.99"],
"9999.9999":["UbuntuServer12.04LTS",1,"1",220,"42.60"]
}
Mind the curly-brackets. This indicates that this is an object.
You cannot iterate through an object by numeric index.
Also mind the duplicated key "9999.9999", the first row will be overwritten by the third row.
You may try to use a for-in loop for looping through an object but this is not recommended.
var basket = JSON.parse(basket);
for(var key in basket)
{
var price = basket[key][4];
// do something with the price.
}
Anyways, this JSON object has structural problem. You should consider a better structure, an plain-old array should be good enough.