Cant receive an access token in Stripe - php

Question

I'm new at Stripe integration. I've read the API documentation for Stripe and here is the OAuth flow. But I still don't receive any OAuth access token. Can someone explain how can I receive an access token? Thanks!
if (isset($_GET['code'])) { // Redirect w/ code
$code = $_GET['code'];
$token_request_body = array(
'grant_type' => 'authorization_code',
'client_id' => 'ca_32D88BD1qLklliziD7gYQvctJIhWBSQ7',
'code' => $code,
'client_secret' => ''
);
$req = curl_init(TOKEN_URI);
curl_setopt($req, CURLOPT_RETURNTRANSFER, true);
curl_setopt($req, CURLOPT_POST, true );
curl_setopt($req, CURLOPT_POSTFIELDS, http_build_query($token_request_body));
// TODO: Additional error handling
$respCode = curl_getinfo($req, CURLINFO_HTTP_CODE);
$resp = json_decode(curl_exec($req), true);
curl_close($req);
echo $resp['access_token'];
} else if (isset($_GET['error'])) { // Error
echo $_GET['error_description'];
} else { // Show OAuth link
$authorize_request_body = array(
'response_type' => 'code',
'scope' => 'read_write',
'client_id' => 'ca_32D88BD1qLklliziD7gYQvctJIhWBSQ7'
);
$url = AUTHORIZE_URI . '?' . http_build_query($authorize_request_body);
echo "<a href='$url'>Connect with Stripe</a>";
}

Answer 1

You should use an OAuth 2.0 client library for this instead of attempting to roll this yourself as suggested by Stripe:
https://stripe.com/docs/connect/standalone-accounts#sample-code
There are many of these, but this is a pretty good option:
https://github.com/thephpleague/oauth2-client
You could modify this example and retrieve the account ID like so:
$provider->getResourceOwner($accessToken)->getId();
Once you retrieve the account ID, you'd store and use this to authenticate as the connected account as suggested by Stripe:
https://stripe.com/docs/connect/authentication#authentication-via-the-stripe-account-header

Answer 2

they actually have, what seems like, an official github library
and they have an example for the oauth thing
just missing in the docs for whatever reason...
https://github.com/stripe/stripe-php/blob/master/examples/oauth.php
in case they delete it, i include the file here, note: they make use of their library, so you have to install it prior to this to work
<?php
require('../init.php');
\Stripe\Stripe::setApiKey(getenv('STRIPE_SECRET_KEY'));
\Stripe\Stripe::setClientId(getenv('STRIPE_CLIENT_ID'));
if (isset($_GET['code'])) {
// The user was redirected back from the OAuth form with an authorization code.
$code = $_GET['code'];
try {
$resp = \Stripe\OAuth::token([
'grant_type' => 'authorization_code',
'code' => $code,
]);
} catch (\Stripe\Error\OAuth\OAuthBase $e) {
exit("Error: " . $e->getMessage());
}
$accountId = $resp->stripe_user_id;
echo "<p>Success! Account <code>$accountId</code> is connected.</p>\n";
echo "<p>Click here to disconnect the account.</p>\n";
} elseif (isset($_GET['error'])) {
// The user was redirect back from the OAuth form with an error.
$error = $_GET['error'];
$error_description = $_GET['error_description'];
echo "<p>Error: code=" . htmlspecialchars($error, ENT_QUOTES) . ", description=" . htmlspecialchars($error_description, ENT_QUOTES) . "</p>\n";
echo "<p>Click here to restart the OAuth flow.</p>\n";
} elseif (isset($_GET['deauth'])) {
// Deauthorization request
$accountId = $_GET['deauth'];
try {
\Stripe\OAuth::deauthorize([
'stripe_user_id' => $accountId,
]);
} catch (\Stripe\Error\OAuth\OAuthBase $e) {
exit("Error: " . $e->getMessage());
}
echo "<p>Success! Account <code>" . htmlspecialchars($accountId, ENT_QUOTES) . "</code> is disconnected.</p>\n";
echo "<p>Click here to restart the OAuth flow.</p>\n";
} else {
$url = \Stripe\OAuth::authorizeUrl([
'scope' => 'read_only',
]);
echo "Connect with Stripe\n";
}