<?php

require 'vendor/autoload.php';

use SpotifyWebAPI\SpotifyWebApi;

$credentails = [
    'clientId' => '2f0f18b01ab0431abdacba3274f0a021',
    'clientSecret' => 'a70e287bd86346318ea0814577a466d4',
];
$callBackUrl = 'http:https://localhost/test/';

// Redirect to spotify for authorization
if(!isset($_GET['code'])) {
    try {
        $spotifyWebApi = new SpotifyWebApi($credentails);
        $url = $spotifyWebApi->getUrlForCodeToken($callBackUrl);
        header("Location: {$url}");
    } catch(\SpotifyWebAPI\SpotifyWebAPIException $e) {
        echo $e->getMessage();
    }
}

// Returned from spotify - get access and refresh token
if(isset($_GET['code'])) {
    try {
        $spotifyWebApi = new SpotifyWebApi($credentails);
        $tokens = $spotifyWebApi->getAccessTokenWithCode(
            $_GET['code'],
            $callBackUrl
        );
        
        echo "Token: {$tokens->access_token}<br>";
        echo "Refresh token: {$tokens->refresh_token}";
        
    } catch(\SpotifyWebAPI\SpotifyWebAPIException $e) {
        echo $e->getMessage();
    }
}

<?php

require 'vendor/autoload.php';

use SpotifyWebAPI\SpotifyWebApi;

function getResults($search) {
    try {
        $spotifyWebApi = new SpotifyWebApi([
            'clientId' => 'YOUR_CLIENT_ID',
            'clientSecret' => 'YOUR_SECRED_ID',
            'accessToken' => 'YOUR_ACCESS_TOKEN', // comes from variable
            'refreshToken' => 'YOUR_REFRESH_TOKEN',
        ]);
        $spotifyWebApi->returnNewTokenIfIsExpired(true);

        $response = $spotifyWebApi->api()->provider(
            \SpotifyWebAPI\SpotifyServices::search()::search($search, 'artist,album,track,playlist')
        )->getResult();

        if(property_exists($response, 'access_token')) {
            // UPDATE YOUR TOKEN (MAYBE IN DATABASE)
            // $response->access_token
            return getResults($search);
        }

        // BOOM! Your results.
        var_dump($response);

    } catch(\SpotifyWebAPI\SpotifyWebAPIException $e) {
        echo $e->getMessage();
    }
}

getResults('prodigy');