Magento 1 API: order.list not working - php

Question

I am using SOAP to use Magento 1 API. It works when I try to use sales_order.info. But when I try to receive the list of the sales, "NULL" is returned. So far I only used example codes from Magento, that's why I am wondering why it is not working.
$mage_url = 'https://myhost/api/?wsdl';
$mage_user = '######';
$mage_api_key = '#######';
$client = new SoapClient( $mage_url );
$session = $client->login( $mage_user, $mage_api_key );
//WORKING:
$sale = $client->call($session, 'sales_order.info', '416203797');
$firstname = $sale['customer_firstname'];
echo $firstname;
//NOT WORKING:
$result = $client->call($session, 'sales_order.list');
var_dump ($result); <-- (result is 'NULL')
Does anybody has an idea why?

Answer 1

check below answer and change as per your requirement. I did this code for my API and it's working perfect. here I have code for "sales_order.list" and "sales_order.info". you can get code as per your requirement.
<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
$config=array();
$config["hostname"] = "www.yoursitename.com";
$config["login"] = "username";
$config["password"] = "password";
$proxy = new SoapClient('http://'.$config["hostname"].'/index.php/api/soap/?wsdl', array('trace'=>1));
$sessionId = $proxy->login($config["login"], $config["password"]);
$result = array();
$orderlist = ($proxy->call($sessionId, 'sales_order.list', array(array('customer_id'=>array('eq'=>$_REQUEST['customer_id'])))));
$order = ($proxy->call($sessionId, 'sales_order.info', array(array('order_info'=>array('eq'=>$_REQUEST['order'])))));
//echo '<pre>';
//print_r($orderlist);
//print_r($order);
//echo '</pre>';
//$result = json_encode($orderlist);
if($orderlist){
$result['success'] = true;
$result['available'] = $orderlist;
$result['available'] = $order;
}
else{
$result['failed'] = false;
$result['not-available'] = error message;
}
echo json_encode($result);
?>