NATS4 API nusoap wsdlcache

When using the SOAP API, you can improve performance on API calls by caching the NATS wsdl file. This article shows an example of using the "nusoap_wsdlcache" to do so.

Including the nusoap_wsdlcache class

To use the "nusoap_wsdlcache" class, be sure to include it at the top of your script making the API calls. If you are using the TMM library version of nusoap, the wsdlcache class may already be included. This example shows how to check for the class before including the individual class file to prevent double inclusion.

<?
/* nusoap includes */
require_once('nusoap/lib/nusoap.php');
if(!class_exists("nusoap_wsdlcache")){ 
	require_once('nusoap/lib/class.wsdlcache.php');
}

Using the nusoap_wsdlcache class

The "nusoap_wsdlcache" class takes 2 parameters when declaring a new instance:

• Directory where cache files will be stored (<cache_dir> in example below)
• The time limit of the cache file in seconds (<wsdl_cache_lifetime> in example below)

The actions taken with this class and the wsdl class are outlined in the code comments below.

/* Nusoap WSDL cache setup */
//cache vars
$cache_dir = "<cache_dir>"; // change <cache_dir> to be the directory for storing cache files
$wsdl_cache_lifetime = <wsdl_cache_lifetime>; // change  <wsdl_cache_lifetime> to an amount in seconds

//construct cache
$wsdlCache = new nusoap_wsdlcache($cache_dir, $wsdl_cache_lifetime);

//try to get cache
$wsdl = $wsdlCache->get($url);
if (is_null($wsdl)) {
	//cache file not found, need to create new one
	$wsdl = new wsdl();
	$wsdl->setCredentials($username,$apikey);// need to login for NATS wsdl 
	$wsdl->fetchWSDL($url); //get the wsdl
	$wsdlCache->put($wsdl); //create cache file
}
$client = new nusoap_client($wsdl, TRUE);
/* end Nusoap WSDL cache setup */

Manually clearing the cache

You can manually clear the cache by going into your <cache_dir> and removing the wsdlcache-XXX, and wsdlcache-XXX.lock file created for the NATS API wsdl.

Full Example

This example code puts the pieces together to make a ping call.

<?

/* Exmple API call using nusoap_wsdlcache class */
/* nusoap includes */
require_once('nusoap/lib/nusoap.php');
if(!class_exists("nusoap_wsdlcache")){ 
	require_once('nusoap/lib/class.wsdlcache.php');
}

//API login vars
$username = '<admin_username>'; // your admin username
$apikey = '<api_key>'; // your api key
$url = 'http://<your_nats_domain>/admin_api.php?wsdl'; // change <your_nats_domain>  to be domain of your NATS install

/* Nusoap WSDL cache setup */
//cache vars
$cache_dir = "<cache_dir>"; // change <cache_dir> to be the directory for storing cache files
$wsdl_cache_lifetime = <wsdl_cache_lifetime>; // change  <wsdl_cache_lifetime> to an amount in seconds

//construct cache
$wsdlCache = new nusoap_wsdlcache($cache_dir, $wsdl_cache_lifetime);

//try to get cache
$wsdl = $wsdlCache->get($url);
if (is_null($wsdl)) {
	//cache file not found, need to create new one
	$wsdl = new wsdl();
	$wsdl->setCredentials($username,$apikey);// need to login for NATS wsdl 
	$wsdl->fetchWSDL($url); //get the wsdl
	$wsdlCache->put($wsdl); //create cache file
}
$client = new nusoap_client($wsdl, TRUE);
/* end Nusoap WSDL cache setup */

//set your login for the soap client
$client->setCredentials($username,$apikey);

// Check for an error
$err = $client->getError();
if ($err) {
    // Display the error
    echo 'Constructor error' . $err . "\n";
    exit; // At this point, you know the call that follows will fail
    
}

//make an API call
$result = $client->call('ping', Array(), 'natsapiadmin_wsdl');
var_dump($result);

Checking the cache improvement

The first time you make an API call using the nusoap wsdlcache, there will still be a request for the wsdl file to start the cache. Once the cache file is created, subsequent API calls will load the wsdl from the cache file rather than trying to request it. You can tail your apache access logs on your NATS server while making API calls to see the cache improvement. When making the call the first time, you will see a "GET" entry to "admin_api.php?wsdl", and a "POST" entry to "POST /admin_api.php". With a valid cache file, you should only see a "POST" entry to "/admin_api.php".