(Perl) HMRC OAuth2 Access Token

See more OAuth2 Examples

Note: This example requires Chilkat v10.1.2 or greater.

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

use chilkat();

# To further clarify, see OAuth 2.0 Authorization Flow

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

# This should be the port in the localhost callback URL for your app.
# Important: Make sure the callback URI in your HMRC developer app 
# is exactly "http://localhost:3017/".  Don't forget the ending "/" char.
# The callback URL would look like "http://localhost:3017/" if the port number is 3017.

# IMPORTANT: Don't forget to setup your HMRC application to use the Redirect URI "http://localhost:3017/" as shown
# here: Configure Redirect URI for HMRC application
$oauth2->put_ListenPort(3017);

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

# Replace with your actual client ID
$oauth2->put_ClientId("HMRC-CLIENT-ID");

# The scopes are documented in the HMRC reference documentation for each API.
# This example gets a read/write access token for the HMRC MTD VAT API.
$oauth2->put_Scope("read:vat write:vat");

# Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
$url = $oauth2->startAuth();
if ($oauth2->get_LastMethodSuccess() != 1) {
    print $oauth2->lastErrorText() . "\r\n";
    exit;
}

# Launch the default browser on the system and navigate to the url.
# The LaunchBrowser method was added in Chilkat v10.1.2.
$success = $oauth2->LaunchBrowser($url);
if ($success == 0) {
    print $oauth2->lastErrorText() . "\r\n";
    exit;
}

# Wait for the user to approve or deny authorization in the browser.
$numMsWaited = 0;
while (($numMsWaited < 90000) and ($oauth2->get_AuthFlowState() < 3)) {
    $oauth2->SleepMs(100);
    $numMsWaited = $numMsWaited + 100;
}

# If the browser does not respond within the specified time, AuthFlowState will be:
# 
# 1: Waiting for Redirect – The OAuth2 background thread is waiting for the browser's redirect request.
# 2: Waiting for Final Response – The thread is awaiting the final access token response.
# In either case, cancel the background task initiated by StartAuth.

if ($oauth2->get_AuthFlowState() < 3) {
    $oauth2->Cancel();
    print "No response from the browser!" . "\r\n";
    exit;
}

# Check AuthFlowState to determine if authorization was granted, denied, or failed:
# 
# 3: Success – OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
# 4: Access Denied – OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
# 5: Failure – OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

if ($oauth2->get_AuthFlowState() == 5) {
    print "OAuth2 failed to complete." . "\r\n";
    print $oauth2->failureInfo() . "\r\n";
    exit;
}

if ($oauth2->get_AuthFlowState() == 4) {
    print "OAuth2 authorization was denied." . "\r\n";
    print $oauth2->accessTokenResponse() . "\r\n";
    exit;
}

if ($oauth2->get_AuthFlowState() != 3) {
    print "Unexpected AuthFlowState:" . $oauth2->get_AuthFlowState() . "\r\n";
    exit;
}

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

# Get the full JSON response:
$json = chilkat::CkJsonObject->new();
$json->Load($oauth2->accessTokenResponse());
$json->put_EmitCompact(0);
print $json->emit() . "\r\n";

# The JSON response looks 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": "..."
# }

# 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 ($json->HasMember("expires_on") != 1) {
    $dtExpire = chilkat::CkDateTime->new();
    $dtExpire->SetFromCurrentSystemTime();
    $dtExpire->AddSeconds($json->IntOf("expires_in"));
    $json->AppendString("expires_on",$dtExpire->getAsUnixTimeStr(0));
}

print $json->emit() . "\r\n";

# Save the JSON to a file for future requests.
$fac = chilkat::CkFileAccess->new();
$fac->WriteEntireTextFile("qa_data/tokens/hmrc.json",$json->emit(),"utf-8",0);