Spotify lyrics API fetch proof of concept

lyrics-poc.php

<?php
/**
 * spotify lyrics proof-of-concept
 *
 * @created      22.09.2022
 * @author       smiley <smiley@chillerlan.net>
 * @copyright    2022 smiley
 * @license      MIT
 */

use chillerlan\HTTP\HTTPOptions;
use chillerlan\HTTP\Psr18\CurlClient;
use chillerlan\HTTP\Psr7\Request;
use chillerlan\HTTP\Psr7\Uri;
use Psr\Http\Client\ClientInterface;
use function chillerlan\HTTP\Utils\decompress_content;
use function chillerlan\HTTP\Utils\get_json;
use function chillerlan\HTTP\Utils\message_to_string;

require_once __DIR__.'/../vendor/autoload.php';

// invoke http client
// @see https://github.com/chillerlan/php-httpinterface
$options = new HTTPOptions([
	'ca_info'    => __DIR__.'/../config/cacert.pem', // https://curl.haxx.se/ca/cacert.pem
	'user_agent' => 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.0.0 Safari/537.36',
]);

$http = new CurlClient($options);

// fetch an anonymous access token
$token = fetch_token($http);

// https://open.spotify.com/track/2OcLJRW0pTyYAxT43N5ccm
$trackID = '2OcLJRW0pTyYAxT43N5ccm?si=b27ec99fa3f14edf';

$json = get_lyrics($http, $token, $trackID);

if(isset($json->lyrics->lines)){
	var_dump(implode(PHP_EOL, array_column($json->lyrics->lines, 'words')));
}


// end - static function declarations below
exit;

/**
 * @throws \Exception
 */
function fetch_token(ClientInterface $http):string{
	$tokenRequest  = new Request('GET', new Uri('https://open.spotify.com/get_access_token'));
	$tokenResponse = $http->sendRequest($tokenRequest);

	if($tokenResponse->getStatusCode() !== 200){
		throw new Exception('could not obtain token');
	}

	$token = get_json($tokenResponse);

	return $token->accessToken;
}

/**
 * @return mixed
 * @throws \Exception
 */
function get_lyrics(ClientInterface $http, string $token, string $trackID){

	$apiUri = (new Uri('https://spclient.wg.spotify.com/color-lyrics/v2/seo/track/'.$trackID))
		->withQuery(http_build_query(['market' => 'from_token']))
	;

	$request = (new Request('GET', $apiUri))
		->withHeader('Accept', 'application/json')
		->withHeader('Accept-Encoding', 'gzip, deflate')
		->withHeader('Authorization', sprintf('Bearer %s', $token))
	;

	$response = $http->sendRequest($request);

	if($response->getStatusCode() !== 200){
		throw new Exception(sprintf(
			"request failed (HTTP/%s)\n\n%s%s\n",
			$response->getStatusCode(),
			message_to_string($request),
			message_to_string($response),
		));
	}

	return json_decode(decompress_content($response));
}