Add possibility to connect using known/stored OpenID access token and cluster

[iranl]

Adds the possibility to optionally pass a known access token and cluster to OpenIdConnectAuthentication.
Designed to be a non-breaking change.

In my use case a cron job is running every 45 minutes to refresh my access token and cluster, which are then stored. When a connection to the API is required the tokens, expiry time and cluster are retrieved and used to connect to Twinfield.

Connection takes about 2 seconds less this way and lessens the total amount of calls to Twinfield when connecting more than 20-30 times/day.

Example:

Cron Job running every 45 minutes:

$refreshToken = retrieveRefreshTokenFromStore();

$provider    = new OAuthProvider([
    'clientId'     => 'someClientId',
    'clientSecret' => 'someClientSecret',
    'redirectUri'  => 'https://example.org/'
]);

$accessToken = $provider->getAccessToken('refresh_token', [
    'refresh_token' => $refreshToken
]);

$validationUrl    = "https://login.twinfield.com/auth/authentication/connect/accesstokenvalidation?token=";
$validationResult = @file_get_contents($validationUrl . urlencode($accessToken->getToken()));

if ($validationResult !== false) {
    $resultDecoded                    = \json_decode($validationResult, true);

    $tokenStorage                     = array();
    $tokenStorage['access_token']     = $accessToken->getToken();
    $tokenStorage['access_expiry']    = $accessToken->getExpires();
    $tokenStorage['access_cluster']   = $resultDecoded["twf.clusterUrl"];

    SaveAccessTokenToStore($tokenStorage);
}

Connection:

$tokenStorage = retrieveAccessTokenFromStore();
$refreshToken = retrieveRefreshTokenFromStore();

$provider    = new OAuthProvider([
    'clientId'     => 'someClientId',
    'clientSecret' => 'someClientSecret',
    'redirectUri'  => 'https://example.org/'
]);

$office = \PhpTwinfield\Office::fromCode("someOfficeCode");

if ($tokenStorage['access_expiry'] > time()) {
    $connection  = new \PhpTwinfield\Secure\OpenIdConnectAuthentication($provider, $refreshToken, $office, $tokenStorage['access_token'], $tokenStorage['access_cluster']);
} else {
    $connection  = new \PhpTwinfield\Secure\OpenIdConnectAuthentication($provider, $refreshToken, $office)
}

[willemstuursma]

Pretty neat. Could you update the readme in the PR on how this would work?

[iranl]

Pretty neat. Could you update the readme in the PR on how this would work?

Done. Also added a note about deprecation of Session Login, information about requesting a client ID/Secret, authorization granting and retrieving the initial access/refresh token

[iranl]

Superseded by #142