Add OAuth2AuthCredentials class and tests

README.md

@@ -107,7 +107,7 @@ First, ensure that the necessary Google Cloud APIs are enabled for your project.
 Next, choose a method for authenticating API requests from within your project:
 
 1. When using `gcloud-java` libraries from within Compute/App Engine, no additional authentication steps are necessary.
-2. When using `gcloud-java` libraries elsewhere, there are two options:
+2. When using `gcloud-java` libraries elsewhere, there are three options:
   * [Generate a JSON service account key](https://cloud.google.com/storage/docs/authentication?hl=en#service_accounts).  After downloading that key, you must do one of the following:
     * Define the environment variable GOOGLE_APPLICATION_CREDENTIALS to be the location of the key.  For example:
     ```bash
@@ -116,11 +116,18 @@ Next, choose a method for authenticating API requests from within your project:
     * Supply the JSON credentials file when building the service options.  For example, this Storage object has the necessary permissions to interact with your Google Cloud Storage data:
     ```java
     Storage storage = StorageOptions.builder()
-      .authCredentials(AuthCredentials.createForJson(new FileInputStream("/path/to/my/key.json"))
+        .authCredentials(AuthCredentials.createForJson(new FileInputStream("/path/to/my/key.json"))
+        .build()
+        .service();
+    ```
+  * If running locally for development/testing, you can use Google Cloud SDK.  Download the SDK if you haven't already, then login using the SDK (`gcloud auth login` in command line).  Be sure to set your project ID as described above.
+  * If you already have an OAuth2 access token, you can use it to authenticate (notice that in this case the access token will not be automatically refreshed):
+  ```java
+  Storage storage = StorageOptions.builder()
+      .authCredentials(AuthCredentials.createFor("your_access_token"))
       .build()
       .service();
-    ```
-  * If running locally for development/testing, you can use use Google Cloud SDK.  Download the SDK if you haven't already, then login using the SDK (`gcloud auth login` in command line).  Be sure to set your project ID as described above.
+  ```
 
 `gcloud-java` looks for credentials in the following order, stopping once it finds credentials:
 

gcloud-java-core/src/main/java/com/google/cloud/AuthCredentials.java

@@ -341,6 +341,67 @@ public RestorableState<AuthCredentials> capture() {
     }
   }
 
+  /**
+   * Represents OAuth2 credentials. These credentials can be created given an OAuth2 access token.
+   * The access token will not be automatically refreshed.
+   */
+  public static class OAuth2AuthCredentials extends AuthCredentials {
+
+    private final GoogleCredentials credentials;
+    private final String accessToken;
+    private final Date expirationTime;
+
+    private static class OAuth2AuthCredentialsState
+        implements RestorableState<AuthCredentials>, Serializable {
+
+      private static final long serialVersionUID = -7760693952274496205L;
+
+      private final String accessToken;
+      private final Date expirationTime;
+
+      private OAuth2AuthCredentialsState(String accessToken, Date expirationTime) {
+        this.accessToken = accessToken;
+        this.expirationTime = expirationTime;
+      }
+
+      @Override
+      public AuthCredentials restore() {
+        return new OAuth2AuthCredentials(accessToken, expirationTime);
+      }
+
+      @Override
+      public int hashCode() {
+        return Objects.hash(accessToken, expirationTime);
+      }
+
+      @Override
+      public boolean equals(Object obj) {
+        if (!(obj instanceof OAuth2AuthCredentialsState)) {
+          return false;
+        }
+        OAuth2AuthCredentialsState other = (OAuth2AuthCredentialsState) obj;
+        return Objects.equals(accessToken, other.accessToken)
+            && Objects.equals(expirationTime, other.expirationTime);
+      }
+    }
+
+    OAuth2AuthCredentials(String accessToken, Date expirationTime) {
+      this.accessToken = checkNotNull(accessToken);
+      this.expirationTime = expirationTime;
+      this.credentials = new GoogleCredentials(new AccessToken(accessToken, expirationTime));
+    }
+
+    @Override
+    public GoogleCredentials credentials() {
+      return credentials;
+    }
+
+    @Override
+    public RestorableState<AuthCredentials> capture() {
+      return new OAuth2AuthCredentialsState(accessToken, expirationTime);
+    }
+  }
+
   /**
    * A placeholder for credentials to signify that requests sent to the server should not be
    * authenticated. This is typically useful when using the local service emulators, such as
@@ -428,6 +489,28 @@ public static ServiceAccountAuthCredentials createFor(String account, PrivateKey
     return new ServiceAccountAuthCredentials(account, privateKey);
   }
 
+  /**
+   * Creates OAuth2 Credentials given the string representation of an access token. The access token
+   * will not be automatically refreshed.
+   *
+   * @param accessToken string representation of an access token
+   * @return the credentials instance
+   */
+  public static OAuth2AuthCredentials createFor(String accessToken) {
+    return createFor(accessToken, (Date) null);
+  }
+
+  /**
+   * Creates OAuth2 Credentials given the string representation of an access token and its
+   * expiration time. The access token will not be automatically refreshed.
+   *
+   * @param accessToken string representation of an access token
+   * @return the credentials instance
+   */
+  public static OAuth2AuthCredentials createFor(String accessToken, Date expirationTime) {
+    return new OAuth2AuthCredentials(accessToken, expirationTime);
+  }
+
   /**
    * Creates a placeholder denoting that no credentials should be used. This is typically useful
    * when using the local service emulators, such as {@code LocalDatastoreHelper} and

gcloud-java-core/src/test/java/com/google/cloud/AuthCredentialsTest.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.cloud;
+
+import static com.google.common.base.Charsets.UTF_8;
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+
+import com.google.auth.oauth2.AccessToken;
+import com.google.auth.oauth2.ServiceAccountCredentials;
+import com.google.cloud.AuthCredentials.OAuth2AuthCredentials;
+import com.google.cloud.AuthCredentials.ServiceAccountAuthCredentials;
+import com.google.common.io.BaseEncoding;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.security.InvalidKeyException;
+import java.security.KeyFactory;
+import java.security.NoSuchAlgorithmException;
+import java.security.PrivateKey;
+import java.security.Signature;
+import java.security.SignatureException;
+import java.security.spec.InvalidKeySpecException;
+import java.security.spec.PKCS8EncodedKeySpec;
+import java.util.Date;
+
+public class AuthCredentialsTest {
+
+  private static final String ACCESS_TOKEN = "accessToken";
+  private static final Date EXPIRATION_DATE = new Date();
+  private static final String SERVICE_ACCOUNT = "[email protected]";
+  private static final String PRIVATE_KEY_STRING = "MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoG"
+      + "BAL2xolH1zrISQ8+GzOV29BNjjzq4/HIP8Psd1+cZb81vDklSF+95wB250MSE0BDc81pvIMwj5OmIfLg1NY6uB1xav"
+      + "OPpVdx1z664AGc/BEJ1zInXGXaQ6s+SxGenVq40Yws57gikQGMZjttpf1Qbz4DjkxsbRoeaRHn06n9pH1ejAgMBAAE"
+      + "CgYEAkWcm0AJF5LMhbWKbjkxm/LG06UNApkHX6vTOOOODkonM/qDBnhvKCj8Tan+PaU2j7679Cd19qxCm4SBQJET7e"
+      + "BhqLD9L2j9y0h2YUQnLbISaqUS1/EXcr2C1Lf9VCEn1y/GYuDYqs85rGoQ4ZYfM9ClROSq86fH+cbIIssqJqukCQQD"
+      + "18LjfJz/ichFeli5/l1jaFid2XoCH3T6TVuuysszVx68fh60gSIxEF/0X2xB+wuPxTP4IQ+t8tD/ktd232oWXAkEAx"
+      + "XPych2QBHePk9/lek4tOkKBgfnDzex7S/pI0G1vpB3VmzBbCsokn9lpOv7JV8071GDlW/7R6jlLfpQy3hN31QJAE10"
+      + "osSk99m5Uv8XDU3hvHnywDrnSFOBulNs7I47AYfSe7TSZhPkxUgsxejddTR27JLyTI8N1PxRSE4feNSOXcQJAMMKJR"
+      + "JT4U6IS2rmXubREhvaVdLtxFxEnAYQ1JwNfZm/XqBMw6GEy2iaeTetNXVlZRQEIoscyn1y2v/No/F5iYQJBAKBOGAS"
+      + "oQcBjGTOg/H/SfcE8QVNsKEpthRrs6CkpT80aZ/AV+ksfoIf2zw2M3mAHfrO+TBLdz4sicuFQvlN9SEc=";
+  private static final String JSON_KEY = "{\n"
+      + "  \"private_key_id\": \"somekeyid\",\n"
+      + "  \"private_key\": \"-----BEGIN PRIVATE KEY-----\\n" + PRIVATE_KEY_STRING
+      + "\\n-----END PRIVATE KEY-----\\n\",\n"
+      + "  \"client_email\": \"[email protected]\",\n"
+      + "  \"client_id\": \"someclientid.apps.googleusercontent.com\",\n"
+      + "  \"type\": \"service_account\"\n"
+      + "}";
+  private static final AuthCredentials NO_AUTH_CREDENTIALS = AuthCredentials.noAuth();
+  private static final OAuth2AuthCredentials OAUTH2_AUTH_CREDENTIALS =
+      AuthCredentials.createFor(ACCESS_TOKEN, EXPIRATION_DATE);
+  private static final byte[] BYTES_TO_SIGN = PRIVATE_KEY_STRING.getBytes(UTF_8);
+
+  private static PrivateKey privateKey;
+  private static byte[] signedBytes;
+
+  @BeforeClass
+  public static void beforeClass() throws NoSuchAlgorithmException, InvalidKeySpecException,
+      InvalidKeyException, SignatureException {
+    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
+    privateKey = keyFactory.generatePrivate(
+        new PKCS8EncodedKeySpec(BaseEncoding.base64().decode(PRIVATE_KEY_STRING)));
+    Signature signature = Signature.getInstance("SHA256withRSA");
+    signature.initSign(privateKey);
+    signature.update(BYTES_TO_SIGN);
+    signedBytes = signature.sign();
+  }
+
+  @Test
+  public void testNoAuthCredentials() {
+    assertSame(NO_AUTH_CREDENTIALS, AuthCredentials.noAuth());
+    assertNull(NO_AUTH_CREDENTIALS.credentials());
+  }
+
+  @Test
+  public void testOAuth2AuthCredentials() {
+    AccessToken accessToken = OAUTH2_AUTH_CREDENTIALS.credentials().getAccessToken();
+    assertEquals(ACCESS_TOKEN, accessToken.getTokenValue());
+    assertEquals(EXPIRATION_DATE, accessToken.getExpirationTime());
+    OAuth2AuthCredentials oAuth2AuthCredentials =
+        AuthCredentials.createFor(ACCESS_TOKEN);
+    accessToken = oAuth2AuthCredentials.credentials().getAccessToken();
+    assertEquals(ACCESS_TOKEN, accessToken.getTokenValue());
+    assertNull(accessToken.getExpirationTime());
+  }
+
+  @Test
+  public void testServiceAccountFromJson() throws IOException, SignatureException {
+    ServiceAccountAuthCredentials serviceAccountAuthCredentials =
+        AuthCredentials.createForJson(new ByteArrayInputStream(JSON_KEY.getBytes()));
+    ServiceAccountCredentials credentials = serviceAccountAuthCredentials.credentials();
+    assertEquals(SERVICE_ACCOUNT, serviceAccountAuthCredentials.account());
+    assertEquals(SERVICE_ACCOUNT, credentials.getClientEmail());
+    assertEquals(privateKey, credentials.getPrivateKey());
+    assertArrayEquals(signedBytes, serviceAccountAuthCredentials.sign(BYTES_TO_SIGN));
+  }
+
+  @Test
+  public void testServiceAccountFromKey() throws IOException, SignatureException {
+    ServiceAccountAuthCredentials serviceAccountAuthCredentials =
+        AuthCredentials.createFor(SERVICE_ACCOUNT, privateKey);
+    ServiceAccountCredentials credentials = serviceAccountAuthCredentials.credentials();
+    assertEquals(SERVICE_ACCOUNT, serviceAccountAuthCredentials.account());
+    assertEquals(SERVICE_ACCOUNT, credentials.getClientEmail());
+    assertEquals(privateKey, credentials.getPrivateKey());
+    assertArrayEquals(signedBytes, serviceAccountAuthCredentials.sign(BYTES_TO_SIGN));
+  }
+}

gcloud-java-core/src/test/java/com/google/cloud/SerializationTest.java

@@ -22,6 +22,7 @@
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.Serializable;
+import java.util.Date;
 
 public class SerializationTest extends BaseSerializationTest {
 
@@ -94,7 +95,8 @@ protected Serializable[] serializableObjects() {
   protected Restorable<?>[] restorableObjects() {
     try {
       return new Restorable<?>[]{AuthCredentials.createForAppEngine(), AuthCredentials.noAuth(),
-          AuthCredentials.createForJson(new ByteArrayInputStream(JSON_KEY.getBytes()))};
+          AuthCredentials.createForJson(new ByteArrayInputStream(JSON_KEY.getBytes())),
+          AuthCredentials.createFor("accessToken", new Date())};
     } catch (IOException ex) {
       // never reached
       throw new RuntimeException(ex);