Enabled Caching of Access Tokens

- Updated AuthTokenCredential to store access token in file storage
- Updated samples to include the configuration to disable/enable caching

sample/bootstrap.php

@@ -40,6 +40,14 @@ return $apiContext;
  */
 function getApiContext($clientId, $clientSecret)
 {
+    // Register the sdk_config.ini file in current directory
+    // as the configuration source.
+    /*
+    if(!defined("PP_CONFIG_PATH")) {
+        define("PP_CONFIG_PATH", __DIR__);
+    }
+    */
+
 
     // ### Api context
     // Use an ApiContext object to authenticate
@@ -60,7 +68,6 @@ function getApiContext($clientId, $clientSecret)
     // Comment this line out and uncomment the PP_CONFIG_PATH
     // 'define' block if you want to use static file
     // based configuration
-
     $apiContext->setConfig(
         array(
             'mode' => 'sandbox',
@@ -68,17 +75,10 @@ function getApiContext($clientId, $clientSecret)
             'log.LogEnabled' => true,
             'log.FileName' => '../PayPal.log',
             'log.LogLevel' => 'FINE',
-            'validation.level' => 'log'
+            'validation.level' => 'log',
+            'cache.enabled' => 'true'
         )
     );
 
-    /*
-    // Register the sdk_config.ini file in current directory
-    // as the configuration source.
-    if(!defined("PP_CONFIG_PATH")) {
-        define("PP_CONFIG_PATH", __DIR__);
-    }
-    */
-
     return $apiContext;
 }

sample/sdk_config.ini

@@ -1,13 +1,11 @@
+;## This is an example configuration file for the SDK.
+;## The sample scripts configure the SDK dynamically
+;## but you can choose to go for file based configuration
+;## in simpler apps (See bootstrap.php for more).
 [Account]
 acct1.ClientId = AYSq3RDGsmBLJE-otTkBtM-jBRd1TCQwFf9RGfwddNXWz0uFU9ztymylOhRS
 acct1.ClientSecret = EGnHDxD_qRPdaLdZz8iCr8N7_MzF-YHPTkjs6NKYQvQSBngp4PTTVWkPZRbL
 
-## This is an example configuration file for the SDK.
-## The sample scripts configure the SDK dynamically
-## but you can choose to go for file based configuration 
-## in simpler apps (See bootstrap.php for more).
-
-
 ;Connection Information
 [Http]
 http.ConnectionTimeOut = 30
@@ -16,11 +14,11 @@ http.Retry = 1
 
 ;Service Configuration
 [Service]
-mode=sandbox ; can be set to sandbox / live 
+; can be set to sandbox / live
+mode = sandbox
 
 ;Logging Information
 [Log]
-
 log.LogEnabled=true
 
 ; When using a relative path, the log file is created
@@ -42,4 +40,16 @@ log.LogLevel=FINE
 ; 'log'     : logs the error message to logger only (default)
 ; 'strict'  : throws a php notice message
 ; 'disable' : disable the validation
-validation.level=strict
+validation.level=log
+
+;Caching Configuration
+[cache]
+; If Cache is enabled, it stores the access token retrieved from ClientId and Secret from the
+; server into a file provided in constant $CACHE_PATH in PayPal/Cache/AuthorizationCache.
+; If the value is set to 'true', it would try to create a file and store the information.
+; For any other value, it would disable it
+; Please note, this is a very good performance improvement, and we would encourage you to
+; set this up properly to reduce the number of calls, to almost 50% on normal use cases
+; PLEASE NOTE: You may need to provide proper write permissions to /var directory under PayPal-PHP-SDK on
+; your hosting server
+cache.enabled=true