json_encode changing array with one value to object - php

Question

I"m creating a PHP script that handles JSON input (via a $_POST variable). It"s extracts data from the JSON and uploads it to an SQL database. I want the JSON in a particular format:
$object = json_decode('{
"key_a":[{"value_a":10,"value_b":7},{"value_a":10,"value_b":7},{"value_a":10,"value_b":7}],
"key_b":[{"value_a":10,"value_b":7}],
"key_c":[{"value_a":10,"value_b":7},{"value_a":10,"value_b":7}]
}',true);
Basically, an object with keys in, each of which should hold an array (no matter what size it is). I use json_decode(json,true) to convert it to an associative array (as opposed to object). I"ve had to add lots of checks in for each of the keys, checking if they"re objects or arrays (as the ASP.net page that the extract comes from converts arrays with single objects in, to objects - removing the array that holds them). The checks then convert them back to arrays, if there"s an object where I"d like an array holding an object:
if(is_object($object["key_b"]))
{
$a = array();
$a[] = $object["key"];
$object["key"] = $a;
}
I then iterate through the array, adding the values to rows in an SQL database. This all works fine, but when converting back to JSON with json_encode, any keys that hold arrays with only one object in, remove the array, and leave just the object under that key:
echo(json_encode($object));
// RETURNED JSON
'{
"key_a":[{"value_a":10,"value_b":7},{"value_a":10,"value_b":7},{"value_a":10,"value_b":7}],
"key_b":{"value_a":10,"value_b":7},
"key_c":[{"value_a":10,"value_b":7},{"value_a":10,"value_b":7}]
}'
You see, key_b no longer holds an array, but an object! This is really annoying, as I plan to create a JavaScript script that iterates through the arrays, adding one DOM element (div) for each of the objects.
Why does this happen? Is there any way to keep them as arrays, even if there"s only one object in the array?
I"ve tried:
if(is_object($object["key_b"]))
{
$a = array();
$a[] = array_values($object["key"]);
$object["key"] = $a;
}
and
if(is_object($object["key_b"]))
{
$a = array();
$a[0] = array_values($object["key"]);
$object["key"] = $a;
}
But it seems like nothing prevents json_encode from affecting the JSON in this way.
It"s not hard to get around this - but it means adding one check per key (checking whether it"s an array or value), which is particularly time consuming as the data extract that comes through is really big.
Any advice would be greatly appreciated.
EDIT: changed ' to " in JSON - though, this is only an example I just wrote to show the structure.
EDIT: I'm using references to cut my coding time down, if this changes anything?:
$t =& $object["key_b"];
if(is_object($t))
{
$a = array();
$a[] = $t;
$t = $a;
}

Answer 1

It appears using is_object() on a key of an associative array will not return true. I just knocked up this example, to prove this:
$json = json_decode('{"job_details":{"a":[{"x":5},{"y":23},{"z":18}],"b":{"x":19},"c":[{"x":64},{"y":132}]}}',true);
echo(json_encode($json)."<br><br>");
$t =& $json["job_details"]["b"];
if(is_object($t))
{
$a = array();
$a[] = $t;
$t = $a;
echo("IS OBJECT<br><br>");
}
echo(json_encode($json));
I will find another means of checking what value is held within an associative arrays key.
I was actually trying to find whether the value in the key is an associative array or not (not an object) - I just didn't realise they were different in PHP.
I must just use this custom function:
function is_assoc($array)
{
return (bool)count(array_filter(array_keys($array), 'is_string'));
}
From: How to check if PHP array is associative or sequential?
Which returns true if the value is an associative array.