(PHP Extension) HMRC OAuth2 Access Token

Demonstrates how to get an HMRC OAuth2 access token from a desktop (installed) application or script. This example gets an HMRC MTD VAT read/write access token.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

$oauth2 = new CkOAuth2();

// 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 these with actual values.
$oauth2->put_ClientId('HMRC-CLIENT-ID');
$oauth2->put_ClientSecret('HMRC-CLIENT-SECRET');

// 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 three-legged flow.  This returns a URL that should be loaded in a browser.
$url = $oauth2->startAuth();
if ($oauth2->get_LastMethodSuccess() != true) {
    print $oauth2->lastErrorText() . "\n";
    exit;
}

$http = new CkHttp();

// At this point, your application should load the URL in a browser.
// For example, 
// in C#: System.Diagnostics.Process.Start(url);
// in Java: Desktop.getDesktop().browse(new URI(url));
// in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
//              wsh.Run url
// in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
// in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
// The GitHub account owner would interactively accept or deny the authorization request.

// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...

// Now wait for the authorization.
// We'll wait for a max of 120 seconds.
$numMsWaited = 0;
while (($numMsWaited < 120000) and ($oauth2->get_AuthFlowState() < 3)) {
    $oauth2->SleepMs(100);
    $numMsWaited = $numMsWaited + 100;
}

// If there was no response from the browser within 30 seconds, then 
// the AuthFlowState will be equal to 1 or 2.
// 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
// 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
// In that case, cancel the background task started in the call to StartAuth.
if ($oauth2->get_AuthFlowState() < 3) {
    $oauth2->Cancel();
    print 'No response from the browser!' . "\n";
    exit;
}

// Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
// The possible AuthFlowState values are:
// 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
// 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
// 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
if ($oauth2->get_AuthFlowState() == 5) {
    print 'OAuth2 failed to complete.' . "\n";
    print $oauth2->failureInfo() . "\n";
    exit;
}

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

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

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

// Get the full JSON response:
$json = new CkJsonObject();
$json->Load($oauth2->accessTokenResponse());
$json->put_EmitCompact(false);
print $json->emit() . "\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') != true) {
    $dtExpire = new CkDateTime();
    $dtExpire->SetFromCurrentSystemTime();
    $dtExpire->AddSeconds($json->IntOf('expires_in'));
    $json->AppendString('expires_on',$dtExpire->getAsUnixTimeStr(false));
}

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

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

?>