Parse json in PHP sent from javascript

Question

I am trying to parse the following json in php:

[{"id":"firstname","optionValue":""},{"id":"lastname","optionValue":""},{"id":"","optionValue":"Submit"}]

Im getting the string sent to me with a get request

This is what i got so far:

if(isset($_GET['data'])) {
 $json_a = json_decode($_GET['data'], true);
 foreach ($json_a as $a => $b) {
 echo $a;
 }
}

However echo $a; does not output anything.

Any ideas?

• Ry-: How are you sending it? Did you inspect the request? Did you make sure the if statement is entered? Are errors on?
• user2959229: The way you have it there right now, you should be seeing the indexes outputted. $b should contain the "lastname" and "optionValue" data.
• Alosyius: I want to get firstname -> value lastname -> value

Answer 1

First of all, make sure you have the JSON string decoded properly by doing a var_dump($json_a);. If the JSON is not valid, json_decode() will return NULL and you won't be able to get the contents.

If you can verify that json_decode() is returning an array containing the required information, keep reading.

You have the following in your code:

foreach ($json_a as $a => $b) {
 echo $a;
}

This will just print out the keys: 0, 1, 2. You want the value instead. For that, your loop needs to look like below:

foreach ($json_a as $value) {
 echo $value['id'].PHP_EOL;
}

This will now print out:

firstname
lastname

Demo!