(PHP ActiveX) Automatically Refresh Token for 401 Unauthorized

Demonstrates how to automatically refresh an access token (without user interaction) when the token expires and a 401 Unauthorized response is received.

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.

$tokenFilePath = 'qa_data/tokens/googleCalendar.json';

// Get our current access token.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.JsonObject')
$jsonToken = new COM("Chilkat.JsonObject");
$success = $jsonToken->LoadFile($tokenFilePath);
if ($jsonToken->HasMember('access_token') == 0) {
    print 'No access token found.' . "\n";
    exit;
}

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Http')
$http = new COM("Chilkat.Http");
$http->AuthToken = $jsonToken->stringOf('access_token');

$jsonResponse = $http->quickGetStr('https://www.googleapis.com/calendar/v3/users/me/calendarList');
if ($http->LastMethodSuccess != 1) {

    if ($http->LastStatus != 401) {
        print $http->LastErrorText . "\n";
        print '----' . "\n";
        print $http->LastResponseBody . "\n";
        exit;
    }

    // The access token must've expired. 
    // Refresh the access token and then retry the request.
    // 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);
    $sbJson->WriteFile($tokenFilePath,'utf-8',0);

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

    // re-try the original request.
    $http->AuthToken = $oauth2->AccessToken;
    $jsonResponse = $http->quickGetStr('https://www.googleapis.com/calendar/v3/users/me/calendarList');
    if ($http->LastMethodSuccess != 1) {
        print $http->LastErrorText . "\n";
        exit;
    }

}

print $jsonResponse . "\n";
print '-----------------------------' . "\n";

?>