Perl Requires Chilkat v10.1.2+

Get GMail SMTP OAuth2 Access Token for Desktop App

See more OAuth2 Examples

This example show how to obtain a Gmail SMTP OAuth2 access token from a desktop application or script, enabling the use of XOAUTH2 authentication. Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# To further clarify, see OAuth 2.0 Authorization Flow

my $oauth2 = Chilkat2::OAuth2->new;

# For Google 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/
# Your app should choose a port not likely not used by any other application.
$oauth2->ListenPort(55568);

$oauth2->AuthorizationEndpoint('https://accounts.google.com/o/oauth2/v2/auth');
$oauth2->TokenEndpoint('https://www.googleapis.com/oauth2/v4/token');

# Replace these with actual values.
$oauth2->ClientId('GOOGLE-CLIENT-ID');
$oauth2->ClientSecret('GOOGLE-CLIENT-SECRET');

# To use Gmail's OAuth2 for sending emails via the SMTP protocol, you need to request the https://mail.google.com/ scope.
# See About GMail SMTP OAuth2 Scopes
$oauth2->Scope('https://mail.google.com/');

# Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
my $url = $oauth2->StartAuth();
if (!$oauth2->LastMethodSuccess) {
    print $oauth2->LastErrorText, "\n";
    exit;
}

# Launch the default browser on the system and navigate to the url.
my $success = $oauth2->LaunchBrowser($url);
if (!$success) {
    print $oauth2->LastErrorText, "\n";
    exit;
}

# Wait for the user to approve or deny authorization in the browser.
my $numMsWaited = 0;
while (($numMsWaited < 90000) && ($oauth2->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->AuthFlowState < 3) {
    $oauth2->Cancel();
    print "No response from the browser!\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->AuthFlowState == 5) {
    print "OAuth2 failed to complete.\n";
    print $oauth2->FailureInfo, "\n";
    exit;
}

if ($oauth2->AuthFlowState == 4) {
    print "OAuth2 authorization was denied.\n";
    print $oauth2->AccessTokenResponse, "\n";
    exit;
}

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

# Save the full JSON access token response to a file.
my $sbJson = Chilkat2::StringBuilder->new;
$sbJson->Append($oauth2->AccessTokenResponse);
$sbJson->WriteFile('qa_data/tokens/_gmailSmtp.json', 'utf-8', 0);

# The saved JSON response looks like this:

#     {
#      "access_token": "ya39.Ci-XA_C5bGgRDC3UaD-h0_NeL-DVIQnI2gHtBBBHkZzrwlARkwX6R3O0PCDEzRlfaQ",
#      "token_type": "Bearer",
#      "expires_in": 3600,
#      "refresh_token": "1/r_2c_7jddspcdfesrrfKqfXtqo08D6Q-gUU0DsdfVMsx0c"
#     }
#
print "OAuth2 authorization granted!\n";
print 'Access Token = ', $oauth2->AccessToken, "\n";