Insert PHP variables into a JSON string - From http://stackoverflow.com/questions/2256307/can-i-insert-php-variables-into-a-json-string
$requestBody = '
{
"attribute": {
"@id": "' . $id . '",
"@uri": "' . $uri . '",
"person": {
"@id": "222",
"@uri": "https://api_name_removed.com/v1/People/222"
},
"attributeGroup": {
"@id": "",
"@uri": "",
"name": null,
"attribute": {
"@id": "2404",
"@uri": "",
"name": null
}
},
"lastUpdatedDate": null
}
}';