Access JSON through variable path in PHP - php

Question

In PHP, how to get a JSON value from a variable path ?
Here is a sample json and a function with 2 params: a json variable, and path split into keys.
$myjson = json_decode('{
"myKey1": {
"myKey2": {
"myKey3": {
"myKey4": "myfinalvalue"
}
}
}
}');
function getJSONValue($myjson, $pathkey) {
// split path keys by ";"
$myjson-> ?? $pathkey ??
}
echo getJSONValue($myjson, "myKey1;myKey2;myKey3;myKey4");
// Should display "myfinalvalue"
the static equivalent would be to do:
$myjson->myKey1->myKey2->myKey3->myKey4;
I tried:
$myjson->$pathkey
but unfortunately, it doesn't work...

Answer 1

Actually, your question has nothing to do with JSON. This is how you can get a value from a nested object:
function getValue($obj, $path) {
foreach(explode(';', $path) as $key) {
$obj = $obj->$key;
}
return $obj;
}
As for the JSON part, your example is not a valid JSON. It should be like this:
$myjson = json_decode('{
"myKey1": {
"myKey2": {
"myKey3": {
"myKey4": "myfinalvalue"
}
}
}
}');
Also, php objects are case-sensitive, if you have myKey in the object, it should be myKey (and not mykey) in the path string.

Answer 2

function getJSONValue($myjson, array $pathkey) {
foreach($pathkey as $val){
$myjson = $myjson->{$val};
}
return $myjson;
}
$myjson = json_decode('{"myKey1": {"myKey2": {"myKey3": {"myKey4": "myfinalvalue"}}}}');
echo getJSONValue($myjson, ["myKey1","myKey2","myKey3","myKey4"]);
live example: http://codepad.viper-7.com/1G78Fi

Answer 3

Something like this:
function getJSONValue() {
$args = func_get_args();
$json = array_shift($args);
$key = array_shift($args);
$value = $json->$key;
if(is_object($value)) {
array_unshift($args, $value);
return call_user_func_array('getJSONValue', $args);
}
return $value;
}
No error checking.

Answer 4

Seems like you are mixing PHP and JS. check this out to see how to create a Json string, then getting an onject out of it, and accessing keys:
$myjson = json_encode(array(
'myKey1' => array(
'mykey2' => array(
'mykey3' => array(
'myKey4' => "myfinalvalue"
)
)
)
));
$obj = json_decode($string);
echo $obj->myKey1->mykey2->mykey3->myKey4
// "myfinalvalue"
or pasting the json directly:
$obj = json_decode(
'{
myKey1: {
mykey2: {
mykey3: {
myKey4: "myfinalvalue"
}
}
}
}');
echo $obj->myKey1->mykey2->mykey3->myKey4
// "myfinalvalue"
To understand it betterm, read about JSON_DECODE