Soundcloud API (PHP) returns "invalid grant" - php

Question

We are using the code below to try to upload tracks from our WordPress site to SoundCloud through PHP. MP3 tracks are already on our server before running this script.
function upload_soundcloud()
{
//App credentials. Create one at http://soundcloud.com/you/apps
define('API_URL', 'https://api.soundcloud.com');
define('CLIENT_ID', '$client_id');
define('CLIENT_SECRET', '$client_secret');
//User credentials
define('EMAIL', '$email');
define('PASSWORD', '$password');
//Path to MP3 file to upload
define('FILE', ABSPATH . '/wp-content/uploads/path/to/file.mp3');
class SoundcloudAPI {
private $url;
private $clientID;
private $secret;
private $accessToken;
public function __construct($url, $clientID, $secret) {
$this->url = $url;
$this->clientID = $clientID;
$this->secret = $secret;
}
public function auth($username, $password) {
$url = $this->url . '/oauth2/token';
$data = array(
'client_id' => $this->clientID,
'client_secret' => $this->secret,
'grant_type' => 'password',
'username' => $username,
'password' => $password
);
$result = $this->request($url, $data, 'POST');
$this->accessToken = $result->access_token;
return $result;
}
public function upload($title, $path) {
$url = $this->url . '/tracks';
$data = array(
'oauth_token' => $this->accessToken,
'track[title]' => $title,
'track[asset_data]' => new CurlFile(realpath($path), 'audio/mpeg'),
);
$result = $this->request($url, $data, 'POST');
return $result;
}
private function request($url, $data, $method) {
$curl = curl_init();
if ($method === 'POST') {
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
} else {
$url .= '?' . http_build_query($data);
}
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
$result = json_decode(curl_exec($curl));
curl_close($curl);
return $result;
}
}
$soundCloud = new SoundcloudAPI(API_URL, CLIENT_ID, CLIENT_SECRET);
$resultAuth = $soundCloud->auth(EMAIL, PASSWORD);
$resultUpload = $soundCloud->upload('Test', FILE);
echo '<pre>';
print_r($resultAuth);
print_r($resultUpload);
echo '</pre>';
}
This is what we are getting as a response:
stdClass Object
(
[error] => invalid_grant
)
Does anyone know why this might be happening? (the strangest part is that it was actually working 2 days ago, but then just stopped working and I feel like I am going crazy).

Answer 1

Try and save the access token and refresh token between requests (for example, in a local file or database) and reusing it. The rate-limit only seems to be on the /oauth2/token endpoint when using a username and password.
Once your access token has expired, you can use the refresh token to get a new one by making a request to /oauth2/token with:
'grant_type': 'refresh_token',
'client_id': <your client id>,
'client_secret': <your client secret>,
'refresh_token': <previous refresh token>