PHP how to create JSON with localization arguments for APNS -

i want send json in apns following:

{     "aps" : {         "alert" : {             "loc-key" : "game_play_request_format",             "loc-args" : [ "jenna", "frank"]         },         "sound" : "default"     }, } 

can explaine how can create in php?

i have following json without key/args:

$body['aps'] = array(        'alert ' => 'this messsage',        'sound' => 'default' );  $payload = json_encode($body); 

i have tried replace 'this message' array loc-key , loc-args not work. jus putting in data string not work..

hope can me. have tried multiple options , variations nothing works..

$body = array(     "aps" => array(         "alert" => array(             "loc-key" => "game_play_request_format",             "loc-args" => array( "jenna", "frank" )         ),         "sound" => "default",     ), ); echo json_encode($body);