(Perl) Get a Xero OAuth2 Access Token via PKCE

See more Xero Examples

Gets a Xero OAuth2 access token via PKCE.

For more information, see https://github.com/XeroAPI/Xero-Postman-Tutorial-PKCE-Edition

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.

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

# For Xero OAuth2, set the listen port equal to the port used
# in the Authorized Redirect URL for the Client ID.
# For example, in this case the Authorized Redirect URL would be http://localhost:55568/
# (The final "/" char is important to include in your Authorized Redirect URL in the Xero application settings in the Xero developer portal.)
# Your app should choose a port not likely not used by any other application.
# See Xero OAuth2 for Desktop Apps for more information.
$oauth2->put_ListenPort(55568);

$oauth2->put_AuthorizationEndpoint("https://login.xero.com/identity/connect/authorize");
$oauth2->put_TokenEndpoint("https://identity.xero.com/connect/token");

# Replace this with your actual Client ID.
$oauth2->put_ClientId("XERO_APP_OAUTH2_CLIENT_ID");

# To use PKCE, enable code challenge and set the code challenge method to "S256".
$oauth2->put_CodeChallenge(1);
$oauth2->put_CodeChallengeMethod("S256");

# See https://developer.xero.com/documentation/oauth2/scopes for a complete list of scopes.
# You will need to change the scopes depending on what access is needed..
$oauth2->put_Scope("openid profile email accounting.transactions accounting.attachments accounting.settings payroll.employees offline_access");

# Begin the OAuth2 three-legged 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;
}

print "URL: " . $url . "\r\n";

# 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        
# in dBASE: run(false, 'rundll32 url.dll,FileProtocolHandler "' + lcUrl + '"')
# The Google 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...
# System.Diagnostics.Process.Start(url);

# Now wait for the authorization.
# We'll wait for a max of 60 seconds.
$numMsWaited = 0;
while (($numMsWaited < 60000) 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!" . "\r\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." . "\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;
}

# Save the full JSON access token response to a file.
$sbJson = chilkat::CkStringBuilder->new();
$sbJson->Append($oauth2->accessTokenResponse());
$sbJson->WriteFile("qa_data/tokens/xero-access-token.json","utf-8",0);

# The saved JSON response looks like this:

# 	{
# 	 "access_token": "...",
# 	 "token_type": "Bearer",
# 	 "expires_in": 3600,
# 	 "refresh_token": "..."
# 	}
# 
print "OAuth2 authorization granted!" . "\r\n";
print "Access Token = " . $oauth2->accessToken() . "\r\n";