How to refresh OAuth 2.0 token

PHP and Java examples to refresh OAuth 2.0 token.

PHP Example

 function runCurl($parameters, $url, $method = 'GET', $postvals = null) {
    $p = array();
    foreach ($parameters as $k = $v) {
        $p[] = $k . '=' . $v;
    }
    $querystring = implode('&', $p);
    $myUrl = $url . '?' . $querystring;
    $ch = curl_init($myUrl);
    $headers = array("Content-Type: application/x-www-form-urlencoded");    
    if ($method == 'GET') {        
        $options = array(
            CURLOPT_URL = $myUrl,
            CURLOPT_RETURNTRANSFER = 1,
            CURLOPT_SSL_VERIFYPEER = FALSE
        );
        $result = curl_setopt_array($ch, $options);        
    } else {        
        $options = array(
            CURLOPT_POST = true,
            CURLOPT_POSTFIELDS = $postvals,
            CURLOPT_HTTPHEADER = $headers,
            CURLOPT_RETURNTRANSFER = 1,
            CURLOPT_SSL_VERIFYPEER = FALSE,
            CURLOPT_HTTPAUTH = CURLAUTH_ANY
        );
        $result = curl_setopt_array($ch, $options);
    }    
    $response = curl_exec($ch);        
    curl_close($ch);
    return $response;
}

function refreshAccessToken($client_id,$client_secret,$refresh_token,$urlToken) {
     $postvals = array(
        "client_id" = $client_id,
        "client_secret" = $client_secret,
        "grant_type" = 'refresh_token',
        "refresh_token" = "$refresh_token"
    );
    $result = runCurl($postvals, $urlToken, 'POST', $postvals);
    $jsonToken = json_decode($result);
    $error = $jsonToken-{'error'};
    if ($error) {
        return false;
    } else {
        return true;
    }
} 

Java Example

This example uses the library codehaus.jackson:

<dependency>
    <groupId>org.codehaus.jackson</groupId>
    <artifactId>jackson-mapper-lgpl</artifactId>
    <version>1.9.13</version>
</dependency> 

import java.io.OutputStream;
import java.net.URL;
import java.net.URLEncoder;
import java.util.Map;
import javax.net.ssl.HttpsURLConnection;
import org.codehaus.jackson.map.ObjectMapper;
import org.junit.Test;
import org.junit.Assert.*;

/**
* Test for refresh oauth token
*/
public class AppTest {

    @Test
    public void refreshTokenTest() throws Exception {
        String client_id = "myClientId";
        String client_secret = "myClientSecret";
        String refresh_token = "xxxxxxxxxx";
        String scope = "full";
        String token_endpoint_url = "https://be-mn1.mag-news.it/be/oauth/token";
        String grant_Type = "refresh_token";

        refresh_access_token(client_id, client_secret, refresh_token, scope, token_endpoint_url, grant_Type);
    }

    public static void refresh_access_token(String client_id, String client_secret, String refresh_token, String scope, String token_endpoint_url, String grant_type) throws Exception {

        String postbody = "grant_type=" + grant_type + ""
                + "&client_id=" + URLEncoder.encode(client_id, "utf-8") 
                + "&scope=" + URLEncoder.encode(scope, "utf-8")
                + "&refresh_token=" + URLEncoder.encode(refresh_token, "utf-8") 
                + "&client_secret=" + URLEncoder.encode(client_secret, "utf-8");

        URL url = new URL(token_endpoint_url);
        HttpsURLConnection con = null;
        try {
            con = (HttpsURLConnection) url.openConnection();
            con.setDoInput(true);
            con.setDoOutput(true);
            con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            con.setRequestMethod("POST");
            try (OutputStream ost = con.getOutputStream();) {
                ost.write(postbody.getBytes("utf-8"));
            }

            ObjectMapper mapper = new ObjectMapper();
            Map result = mapper.readValue(con.getInputStream(), Map.class);
            String error = (String) result.get("error");
            if (error != null) {
                throw new Exception("error while using refresh token: " + result);
            }
            
        } finally {
            if (con != null){
                con.disconnect();
            }
        }

    }
}