(Perl) Refresh HMRC OAuth2 Access Token

Demonstrates how to refresh an HMRC access token.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

# See Get HMRC Access Token 
# for sample code showing how to obtain a HMRC access token for desktop apps.

# It is assumed we previously obtained an OAuth2 access token for HMRC.

$jsonToken = chilkat::CkJsonObject->new();
$success = $jsonToken->LoadFile("qa_data/tokens/hmrc.json");
if ($success != 1) {
    print "Failed to load hmrc.json" . "\r\n";
    exit;
}

# The access token JSON looks something like this:

# {
#   "token_type": "Bearer",
#   "scope": "user_impersonation",
#   "expires_in": "3599",
#   "ext_expires_in": "0",
#   "expires_on": "1524783438",
#   "not_before": "1524779538",
#   "resource": "https://mydomain.api.crm.dynamics.com",
#   "access_token": "...",
#   "refresh_token": "...",
#   "id_token": "..."
# }

$oauth2 = chilkat::CkOAuth2->new();

$oauth2->put_TokenEndpoint("https://test-api.service.hmrc.gov.uk/oauth/token");

# Replace these with actual values.
$oauth2->put_ClientId("HMRC-CLIENT-ID");
$oauth2->put_ClientSecret("HMRC-CLIENT-SECRET");

# Get the "refresh_token"
$oauth2->put_RefreshToken($jsonToken->stringOf("refresh_token"));

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

# Load the access token response into the json object 
$jsonToken->Load($oauth2->accessTokenResponse());

# If an "expires_on" member does not exist, then add the JSON member by
# getting the current system date/time and adding the "expires_in" seconds.
# This way we'll know when the token expires.
if ($jsonToken->HasMember("expires_on") == 0) {
    $dtExpire = chilkat::CkDateTime->new();
    $dtExpire->SetFromCurrentSystemTime();
    $dtExpire->AddSeconds($jsonToken->IntOf("expires_in"));
    $jsonToken->AppendString("expires_on",$dtExpire->getAsUnixTimeStr(0));
}

# Save the new JSON access token response to a file.
# The access + refresh tokens contained in this JSON will be needed for the next refresh.
$sbJson = chilkat::CkStringBuilder->new();
$jsonToken->put_EmitCompact(0);
$jsonToken->EmitSb($sbJson);
$sbJson->WriteFile("qa_data/tokens/hmrc.json","utf-8",0);

print "OAuth2 authorization granted!" . "\r\n";
print "New Access Token = " . $oauth2->accessToken() . "\r\n";