sending push notification with vapid keys - php

Question

can someone assist where i am doing mistake
generate vapid keys and store them
use push-api and store endpoint, p256dh and auth
send push notification using webPush protocol
but getting this at 3rd stage
Warning: openssl_sign(): Supplied key param cannot be coerced into a private key
code from 1 to 3 please go through
generate VAPID keys in php on server side and store them
// Generate VAPID keys
$private_key = openssl_pkey_new([
'private_key_type' => OPENSSL_KEYTYPE_EC,
'curve_name' => 'prime256v1',
]);
$details = openssl_pkey_get_details($private_key);
$private_key_raw = $details['ec']['d'];
$public_key_raw = $details['ec']['x'] . $details['ec']['y'];
$auth_token = base64_encode(openssl_random_pseudo_bytes(16));
$vapid = [
'private_key' => rtrim(strtr(base64_encode($private_key_raw), '+/', '-_'), '='),
'public_key' => rtrim(strtr(base64_encode($public_key_raw), '+/', '-_'), '='),
'auth_token' => $auth_token,
];
echo json_encode($vapid);
generate applicationServerKey using public key
$publicKey = 'SzRJTTxfRvvoIfYJye-Oj-xJ-eDxHjIBhPLxILieNbZ86KjRE_EIvdjdKDmUH9RLwgmkITs-v_z_6J44aP1TtA';
// Base64-decode the public key
$public_key_bytes = base64_decode($publicKey);
// Check that the public key has the correct format
if (strlen($public_key_bytes) != 65 || ord($public_key_bytes[0]) != 4) {
// The public key has an incorrect format
// Handle the error here
}
// Extract the x and y coordinates of the point
$x = substr($public_key_bytes, 1, 32);
$y = substr($public_key_bytes, 33, 32);
// Pack the bytes of the public key in the correct order
$application_server_key = "\x04" . $x . $y;
echo base64_encode($application_server_key);
use the base64 applicationServerKey on client side
let b64ASK = 'BDRJTTxfRvvoIfYJyeOjxJeDxHjIBhPLxILieNbZ86KjREEIvdjdKDmUH9RLwgmkITsvz6J44aP1TtAauthtokc=';
let asKey = encodeToUint8Array(b64ASK);
pushManager.subscribe({applicationServerKey:asKey,userVisibleOnly:true})
.then(subscription=>{console.log(subscription.toJSON())})
store endpoint,p256dh,auth and send push notification using vapid keys on server side
send-notification.php
$publicKey = 'SzRJTTxfRvvoIfYJye-Oj-xJ-eDxHjIBhPLxILieNbZ86KjRE_EIvdjdKDmUH9RLwgmkITs-v_z_6J44aP1TtA';
$privateKey = '-----BEGIN EC PRIVATE KEY-----
Lnp9eUjWE7o8oqneZPzOW8nbz7hTVosE25sJm47Arrg=
-----END EC PRIVATE KEY-----';
$endpoint = "https://fcm.googleapis.com/fcm/send/cI0XqQ4quFM:APA91bExZFUuSZ9lgTDJQqmrHJpV-w5pIVnvaiODI9WIeER-K0Vg0U5P8wfTslRF5KdTlCmF9_Tp7bpAohKLxLvQCuS2Cy6ZG2BpVKO4f0wLWrfU-mGD6GCMCVUYLna3uwDLR6NqZxNi";
$auth = "X6syP0cUxjDjMAcUunH3FA";
$p256dh = "BIUuCWdoJykH6u3vERcfZe8gxEx1ajaFTPGnM4cWdYv-Hp-qRgt5GShAtbFYRr5my8hH66uIJEiHf22XW_i_Bps";
// Set the payload for the notification
$payload = [
'title' => 'push-message-test',
'body' => 'This is a test notification using VAPID.',
'icon' => 'assets/icons/favicon-32x32.png',
];
// Encode the payload as a JSON string
$payloadJson = json_encode($payload);
// Generate the JWT header
$header = [
'alg' => 'ES256',
'typ' => 'JWT',
];
$headerJson = json_encode($header);
$headerBase64Url = str_replace(['+', '/', '='], ['-', '_', ''], base64_encode($headerJson));
// Generate the JWT claim
$now = time();
$exp = $now + (12 * 60 * 60); // 12 hours in the future
$claim = [
'aud' => $endpoint,
'exp' => $exp,
'sub' => 'https://example.com',
];
$claimJson = json_encode($claim);
$claimBase64Url = str_replace(['+', '/', '='], ['-', '_', ''], base64_encode($claimJson));
// Generate the JWT signature
$signingString = $headerBase64Url . '.' . $claimBase64Url;
$signature = '';
$privateKeyResource = openssl_pkey_get_private($privateKey);
openssl_sign($signingString, $signature, $privateKeyResource, 'sha256');
// Encode the signature as base64url
$signatureBase64Url = str_replace(['+', '/', '='], ['-', '_', ''], base64_encode($signature));
// Combine the JWT components into a string
$jwt = $headerBase64Url . '.' . $claimBase64Url . '.' . $signatureBase64Url;
// Send the notification using the Web Push protocol
$headers = [
'Authorization: Bearer ' . $jwt,
'Crypto-Key: p256ecdsa=' . $publicKey,
'Content-Length: ' . strlen($payloadJson),
'Content-Type: application/json',
];
$data = [
'endpoint' => $endpoint,
'publicKey' => $p256dh,
'authToken' => $auth,
'payload' => $payloadJson,
];
$options = [
'http' => [
'header' => implode("\r\n", $headers),
'method' => 'POST',
'content' => json_encode($data),
],
];
$context = stream_context_create($options);
$result = file_get_contents($endpoint, false, $context);
// Handle the response
if ($result === false) {
// Error handling
echo 'failed to send push';
} else {
// Success handling
echo 'succesfully sent push using push protocol';
}