1309: added /oauth2/ client creds support

Author: lhazlewood

impl/src/main/java/com/stormpath/sdk/impl/http/authc/SswsAuthenticator.java

@@ -1,23 +1,53 @@
 package com.stormpath.sdk.impl.http.authc;
 
+import com.stormpath.sdk.api.ApiKey;
+import com.stormpath.sdk.client.PairedApiKey;
 import com.stormpath.sdk.impl.authc.credentials.ApiKeyCredentials;
 import com.stormpath.sdk.impl.http.Request;
 import com.stormpath.sdk.impl.http.support.RequestAuthenticationException;
+import com.stormpath.sdk.impl.util.Base64;
 import com.stormpath.sdk.lang.Assert;
 
+import java.nio.charset.Charset;
+
 public class SswsAuthenticator implements RequestAuthenticator {
 
     public static final String AUTHENTICATION_SCHEME = "SSWS";
 
+    public static final Charset UTF8 = Charset.forName("UTF-8");
+
     private final ApiKeyCredentials apiKeyCredentials;
+    private final PairedApiKey pairedApiKey;
 
     public SswsAuthenticator(ApiKeyCredentials apiKeyCredentials) {
         Assert.notNull(apiKeyCredentials, "apiKeyCredentials must be not be null.");
         this.apiKeyCredentials = apiKeyCredentials;
+
+        ApiKey apiKey = apiKeyCredentials.getApiKey();
+        Assert.notNull(apiKey, "apiKeyCredentials argument cannot have a null apiKey");
+
+        Assert.isInstanceOf(PairedApiKey.class, apiKey, "apiKeyCredentials.getApiKey() must be a PairedApiKey instance");
+        this.pairedApiKey = (PairedApiKey) apiKey;
     }
 
     @Override
     public void authenticate(Request request) throws RequestAuthenticationException {
+
+        if (request.getResourceUrl().getPath().startsWith("/oauth2/")) {
+
+            ApiKey oauthClientCreds = this.pairedApiKey.getSecondaryApiKey();
+            Assert.notNull(oauthClientCreds, "PairedApiKey credentials must have a secondary api key when invoking an Okta /oauth2/ endpoint.");
+
+            String basicCreds = oauthClientCreds.getId() + ":" + oauthClientCreds.getSecret();
+            String base64 = Base64.encodeBase64String(basicCreds.getBytes(UTF8));
+
+
+            request.getHeaders().set(AUTHORIZATION_HEADER, "BASIC " + base64);
+
+            return;
+        }
+
+
         request.getHeaders().set(AUTHORIZATION_HEADER, AUTHENTICATION_SCHEME + " " + apiKeyCredentials.getSecret());
     }
 }