Unable to get request token from 3rd party Magento REST API

Question

One of my customer has setup Magento on their end. Now, I'm trying to access their Magento APIs to fetch product information. They have provided me the Magento hostname, consumerkey, and consumersecret. I'm using Java w/ Scribe 1.3.7 for accessing the APIs. This is my code:

public final class MagentoThreeLeggedOAuth extends DefaultApi10a {
 private static final String BASE_URL = "http://example.com/";
 @Override
 public String getRequestTokenEndpoint() {
 return BASE_URL + "oauth/initiate";
 }
 @Override
 public String getAccessTokenEndpoint() {
 return BASE_URL + "oauth/token";
 }
 @Override
 public String getAuthorizationUrl(Token requestToken) {
 return BASE_URL + "admin/oauth_authorize?oauth_token="
 + requestToken.getToken(); //this implementation is for admin roles only...
 }
}
public final class MagentoAuth {
 /**
 * @param args
 */
 public static void main(String[] args) {
 final String MAGENTO_API_KEY = "abcdefghij";
 final String MAGENTO_API_SECRET = "qwertyuiop";
 final String MAGENTO_REST_API_URL = "http://example.com/magento/api/rest"; 
 // three-legged oauth
 OAuthService service = new ServiceBuilder()
 .provider(MagentoThreeLeggedOAuth.class)
 .apiKey(MAGENTO_API_KEY)
 .apiSecret(MAGENTO_API_SECRET)
 .debug()
 .build();
 System.out.println("" + service.getVersion());
 Scanner in = new Scanner(System.in);
 System.out.println("Magento's OAuth Workflow");
 System.out.println();
 // Obtain the Request Token
 System.out.println("Fetching the Request Token...");
 Token requestToken = service.getRequestToken();
 System.out.println("Got the Request Token!");
 System.out.println();
 System.out.println("Fetching the Authorization URL...");
 String authorizationUrl = service.getAuthorizationUrl(requestToken);
 System.out.println("Got the Authorization URL!");
 System.out.println("Now go and authorize Main here:");
 System.out.println(authorizationUrl);
 System.out.println("And paste the authorization code here");
 System.out.print(">>");
 Verifier verifier = new Verifier(in.nextLine());
 System.out.println();
 System.out.println("Trading the Request Token for an Access Token...");
 Token accessToken = service.getAccessToken(requestToken, verifier);
 System.out.println("Got the Access Token!");
 System.out.println("(if your curious it looks like this: "
 + accessToken + " )");
 System.out.println();
 OAuthRequest request = new OAuthRequest(Verb.GET, MAGENTO_REST_API_URL+ "/products");
 service.signRequest(accessToken, request);
 Response response = request.send();
 System.out.println();
 System.out.println(response.getCode());
 System.out.println(response.getBody());
 System.out.println();
 }
}

When I try to run the program, I get the following error:

1.0
Magento's OAuth Workflow
Fetching the Request Token...
obtaining request token from http://example.com/oauth/initiate
setting oauth_callback to oob
generating signature...
using base64 encoder: DatatypeConverter
base string is: POST&http%3A%2F%2Fexample.com%2Foauth%2Finitiate&oauth_callback%3Doob%26oauth_consumer_key%3Dabcdefghij%26oauth_nonce%3D2387862876%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1437522397%26oauth_version%3D1.0
signature is: 7DHYSmiU9JMnek04Pd8JwtbaeP4=
appended additional OAuth parameters: { oauth_callback -> oob , oauth_signature -> 7DHYSmiU9JMnek04Pd8JwtbaeP4= , oauth_version -> 1.0 , oauth_nonce -> 2387862876 , oauth_signature_method -> HMAC-SHA1 , oauth_consumer_key -> abcdefghij , oauth_timestamp -> 1437522397 }
using Http Header signature
sending request...
response status code: 400
response body: oauth_problem=parameter_absent&oauth_parameters_absent=oauth_consumer_key
Exception in thread "main" org.scribe.exceptions.OAuthException: Response body is incorrect. Can't extract token and secret from this: 'oauth_problem=parameter_absent&oauth_parameters_absent=oauth_consumer_key'

What is the problem here? Does it have anything to do with the code? Or does my customer have to do something on their end? I installed Magento locally, and I'm able to get the access token using this code. I do not want to go back to my customer without first understanding what the problem is.

Thanks.

• B00MER: Have them enable WS-I compliance. magentocommerce.com/api/soap/wsi_compliance.html
• B00MER: Also stackoverflow.com/questions/29742468/…
• drunkenfist: @B00MER Isn't WS-I compliance for SOAP? I'm using REST API.
• drunkenfist: Moreover, it is working when I try to access my local Magento server, even though I have disable WS-I compliance.
• B00MER: Sorry didn't see you were using REST. You may try a browser based REST client to test if its on your end or theirs. Firefox: addons.mozilla.org/en-US/firefox/addon/restclient Chrome: chrome.google.com/webstore/detail/advanced-rest-client/…