(PHP ActiveX) Google Calendar -- Refresh an Expired Access Token

See more Google Calendar Examples

Demonstrates how to refresh an expired access token. If a Google Calendar REST API call results in a 401 "unauthorized" response, then it is likely the access token expired. An application should be able to automatically refresh the access token with no user interaction and then re-try the request with the newly obtained access token.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// It is assumed we previously obtained an OAuth2 access token.
// This example loads the JSON access token file 
// saved by this example: Get Google Calendar OAuth2 Access Token

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.JsonObject')
$jsonToken = new COM("Chilkat.JsonObject");
$success = $jsonToken->LoadFile('qa_data/tokens/googleCalendar.json');
if ($success != 1) {
    print 'Failed to load googleCalendar.json' . "\n";
    exit;
}

// The access token JSON looks like this:

// 	{ 
// 	 "access_token": "abac.Ci-ZabcdF37-NUrmSzxbHxTsMbtlN-uPfabcdAQN_2ekzj0s5ofCzRabcdTDMGaa2Q",
// 	 "token_type": "Bearer",
// 	 "expires_in": 3600,
// 	 "refresh_token": "1/lEe5abcdNJ77eOSDBabcdkQGVmDalkwabcdR2Hatbo"
// 	}
// 

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.OAuth2')
$oauth2 = new COM("Chilkat.OAuth2");

$oauth2->TokenEndpoint = 'https://www.googleapis.com/oauth2/v4/token';

// Replace these with actual values.
$oauth2->ClientId = 'GOOGLE-CLIENT-ID';
$oauth2->ClientSecret = 'GOOGLE-CLIENT-SECRET';

// Get the "refresh_token"
$oauth2->RefreshToken = $jsonToken->stringOf('refresh_token');

// Send the HTTP POST to refresh the access token..
$success = $oauth2->RefreshAccessToken();
if ($success != 1) {
    print $oauth2->LastErrorText . "\n";
    exit;
}

// The response contains a new access token, but we must keep
// our existing refresh token for when we need to refresh again in the future.
$jsonToken->UpdateString('access_token',$oauth2->AccessToken);

// Save the new JSON access token response to a file.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.StringBuilder')
$sbJson = new COM("Chilkat.StringBuilder");
$jsonToken->EmitCompact = 0;
$jsonToken->EmitSb($sbJson);
$sbJson->WriteFile('qa_data/tokens/googleCalendar.json','utf-8',0);

print 'OAuth2 authorization granted!' . "\n";
print 'New Access Token = ' . $oauth2->AccessToken . "\n";

?>