Java Client Credentials Grant Example

ClientCredentialsExample.java

/*
 * A simple example of a Client Credentials Grant against Globus Auth
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import javax.net.ssl.HttpsURLConnection;
import java.net.URL;
import java.util.Base64;
import java.nio.charset.StandardCharsets;


public class ClientCredentialsExample {
    public static void main (String args[]) {
        try {
            // url to use
            URL url = new URL("https://auth.globus.org/v2/oauth2/token");
            // create a connection for POST requests
            HttpsURLConnection con = (HttpsURLConnection) url.openConnection();
            con.setRequestMethod("POST");
            con.setDoOutput(true);
            // set the content-type for a form post
            con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
            // apply basic auth
            String auth = "Basic " + Base64.getEncoder().encodeToString("CLIENT_ID:CLIENT_SECRET".getBytes(StandardCharsets.UTF_8));
            con.setRequestProperty("Authorization", auth);
            // form formatted payload body
            byte[] payload = "grant_type=client_credentials&scope=urn:globus:auth:scope:transfer.api.globus.org:all".getBytes(StandardCharsets.UTF_8);
            // connect and send the payload
            con.connect();
            OutputStream outstream = con.getOutputStream();
            outstream.write(payload);

            int code = con.getResponseCode();
            System.out.println(code);

            try(BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(), "utf-8"))){
                StringBuilder response = new StringBuilder();
                String responseLine = null;
                while ((responseLine = br.readLine()) != null) {
                    response.append(responseLine.trim());
                }
                System.out.println(response.toString());
            }
        } catch (Exception e) {
            System.err.println("uh-oh");
        }
    }
}