Pesomka/cach miss exception (#105)

* acquire token silently throwing exception for cache miss

Author: SomkaPe

src/main/java/com/microsoft/aad/msal4j/AcquireTokenSilentSupplier.java

@@ -28,31 +28,35 @@ AuthenticationResult execute() throws Exception {
                     requestAuthority,
                     silentRequest.parameters().scopes(),
                     clientApplication.clientId());
-            return StringHelper.isBlank(res.accessToken()) ? null : res;
         }
+        else {
+            res = clientApplication.tokenCache.getCachedAuthenticationResult(
+                    silentRequest.parameters().account(),
+                    requestAuthority,
+                    silentRequest.parameters().scopes(),
+                    clientApplication.clientId());
 
-        res = clientApplication.tokenCache.getCachedAuthenticationResult(
-                silentRequest.parameters().account(),
-                requestAuthority,
-                silentRequest.parameters().scopes(),
-                clientApplication.clientId());
-
-        if (!silentRequest.parameters().forceRefresh() && !StringHelper.isBlank(res.accessToken())) {
-            return res;
-        }
+            if (silentRequest.parameters().forceRefresh() || StringHelper.isBlank(res.accessToken())) {
 
-        if (!StringHelper.isBlank(res.refreshToken())) {
-            RefreshTokenRequest refreshTokenRequest = new RefreshTokenRequest(
-                    RefreshTokenParameters.builder(silentRequest.parameters().scopes(), res.refreshToken()).build(),
-                    silentRequest.application(),
-                    silentRequest.requestContext());
+                if (!StringHelper.isBlank(res.refreshToken())) {
+                    RefreshTokenRequest refreshTokenRequest = new RefreshTokenRequest(
+                            RefreshTokenParameters.builder(silentRequest.parameters().scopes(), res.refreshToken()).build(),
+                            silentRequest.application(),
+                            silentRequest.requestContext());
 
-            AcquireTokenByAuthorizationGrantSupplier acquireTokenByAuthorisationGrantSupplier =
-                    new AcquireTokenByAuthorizationGrantSupplier(clientApplication, refreshTokenRequest, requestAuthority);
+                    AcquireTokenByAuthorizationGrantSupplier acquireTokenByAuthorisationGrantSupplier =
+                            new AcquireTokenByAuthorizationGrantSupplier(clientApplication, refreshTokenRequest, requestAuthority);
 
-            return acquireTokenByAuthorisationGrantSupplier.execute();
-        } else {
-            return null;
+                    res = acquireTokenByAuthorisationGrantSupplier.execute();
+                }
+                else{
+                    res = null;
+                }
+            }
+        }
+        if(res == null || StringHelper.isBlank(res.accessToken())){
+            throw new MsalClientException(AuthenticationErrorMessage.NO_TOKEN_IN_CACHE, AuthenticationErrorCode.CACHE_MISS);
         }
+        return res;
     }
 }

src/main/java/com/microsoft/aad/msal4j/AuthenticationErrorCode.java

@@ -41,6 +41,11 @@ public class AuthenticationErrorCode {
      */
     public final static String USER_REALM_DISCOVERY_FAILED = "user_realm_discovery_failed";
 
+    /**
+     * Not found in the cache
+     */
+    public final static String CACHE_MISS = "cache_miss";
+
     /**
      * Unknown error occurred
      */

src/main/java/com/microsoft/aad/msal4j/AuthenticationErrorMessage.java

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package com.microsoft.aad.msal4j;
+
+public class AuthenticationErrorMessage {
+
+    /**
+     * Token not found it the cache
+     */
+    public final static String NO_TOKEN_IN_CACHE = "Token not found it the cache";
+}

src/samples/msal-web-sample/src/main/java/com/microsoft/azure/msalwebsample/AuthHelper.java

@@ -76,10 +76,6 @@ IAuthenticationResult getAuthResultBySilentFlow(HttpServletRequest httpRequest,
             throw e.getCause();
         }
 
-        if (updatedResult == null) {
-            throw new ServiceUnavailableException("authentication result was null");
-        }
-
         //update session with latest token cache
         storeTokenCacheInSession(httpRequest, app.tokenCache().serialize());
 

src/test/java/com/microsoft/aad/msal4j/AcquireTokenSilentlyTest.java

@@ -0,0 +1,50 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package com.microsoft.aad.msal4j;
+
+import org.powermock.modules.testng.PowerMockTestCase;
+import org.testng.annotations.Test;
+
+import java.util.Collections;
+import java.util.concurrent.CompletionException;
+
+@Test(groups = { "checkin" })
+public class AcquireTokenSilentlyTest extends PowerMockTestCase {
+
+    @Test(expectedExceptions = MsalClientException.class,
+            expectedExceptionsMessageRegExp = AuthenticationErrorMessage.NO_TOKEN_IN_CACHE)
+    public void publicAppAcquireTokenSilently_emptyCache_MsalClientException() throws Throwable {
+
+        PublicClientApplication application = PublicClientApplication
+                .builder(TestConfiguration.AAD_CLIENT_ID)
+                .b2cAuthority(TestConfiguration.B2C_AUTHORITY).build();
+
+        SilentParameters parameters = SilentParameters.builder(Collections.singleton("scope")).build();
+
+        try {
+            application.acquireTokenSilently(parameters).join();
+        }
+        catch (CompletionException ex){
+            throw ex.getCause();
+        }
+    }
+
+    @Test(expectedExceptions = MsalClientException.class,
+            expectedExceptionsMessageRegExp = AuthenticationErrorMessage.NO_TOKEN_IN_CACHE)
+    public void confidentialAppAcquireTokenSilently_emptyCache_MsalClientException() throws Throwable {
+
+        ConfidentialClientApplication application = ConfidentialClientApplication
+                .builder(TestConfiguration.AAD_CLIENT_ID, ClientCredentialFactory.create(TestConfiguration.AAD_CLIENT_SECRET))
+                .b2cAuthority(TestConfiguration.B2C_AUTHORITY).build();
+
+        SilentParameters parameters = SilentParameters.builder(Collections.singleton("scope")).build();
+
+        try {
+            application.acquireTokenSilently(parameters).join();
+        }
+        catch (CompletionException ex){
+            throw ex.getCause();
+        }
+    }
+}