(PHP Extension) Facebook OAuth2 Access Token

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

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<?php

include("chilkat.php");
// Use "chilkat_9_5_0.php" for versions of Chilkat < 10.0.0

// To further clarify, see OAuth 2.0 Authorization Flow

$oauth2 = new CkOAuth2();

// This should match the Site URL configured for your Facebook APP, such as "http://localhost:3017/"
$oauth2->put_ListenPort(3017);

$oauth2->put_AuthorizationEndpoint('https://www.facebook.com/dialog/oauth');
$oauth2->put_TokenEndpoint('https://graph.facebook.com/oauth/access_token');

// Replace this with your actual App ID
$oauth2->put_ClientId('APP_ID');

// Set the Scope to a comma-separated list of permissions the app wishes to request.
// See https://developers.facebook.com/docs/facebook-login/permissions/ for a full list of permissions.
$oauth2->put_Scope('public_profile,user_friends,email,user_posts,user_likes,user_photos');

// This is for Require Proof Key for Code Exchange (PKCE)
// See OAuth2 PKCE Explained
$oauth2->put_CodeChallenge(true);
$oauth2->put_CodeChallengeMethod('S256');

// Begin the OAuth2 Authorization code 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;
}

print 'url = ' . $url . "\n";

// 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 == false) {
    print $oauth2->lastErrorText() . "\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!' . "\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.' . "\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";

?>