PHP issues appending to json file, code results in an array full of null

Question

I'm trying to append new items to the end of my json file. When the code runs as below, it keeps appending null instead of the new items. I've searched around and haven't found any solutions yet.

Here's the PHP:

$_POST["carMake"] = 'toyota'; 
$_POST["startProduction"] = '258147369';
$_POST["endProduction"] = '369258147';

$file = "cars.json";
$jsonArray = json_decode(file_get_contents($file), true);
array_push($jsonArray[], array( 'Make' => $_POST["carMake"], 'Start Prod' => $_POST["startProduction"], 'End Prod' => $_POST["endProduction"] ));
file_put_contents($file, json_encode($jsonArray));

$answer = array ( 'Created' => "true", 'validation' => "Car added");
return json_encode($answer);

The intended output is:

    [
     {
      "Make":"Toyota",
      "Start Prod":258147369,
      "End Prod":369147258
     },
     {
      "Make":"BMW",
      "start":789456123,
      "end":159487263
     },
    ]

Answer 1

array_push($jsonArray[], ... is wrong. You should either do:

$jsonArray[] = ...

or:

array_push($jsonArray, ...

not both.

Answer 2

Try this as PHP manual said that. http://www.php.net/manual/en/function.array-push.php

$_POST["carMake"] = 'toyota'; 
$_POST["startProduction"] = '258147369';
$_POST["endProduction"] = '369258147';

$file = "cars.json";
$jsonArray = json_decode(file_get_contents($file), true);
$jsonArray[]= array( 'Make' => $_POST["carMake"], 'Start Prod' => $_POST["startProduction"], 'End Prod' => $_POST["endProduction"] );
file_put_contents($file, json_encode($jsonArray));

$answer = array ( 'Created' => "true", 'validation' => "Car added");
return json_encode($answer);