Gmail API设置与服务帐户，而不是O认证客户端ID

Question

我注意到Google Storage使用了一些创建凭据的方法来启动服务。Gmail的对应功能是什么?我不想创建一个O认证客户端Id。我在下面附上了Gmail快速入门指南，它使用O认证客户端ID。

我也试过查看文档，但我找不到O认证客户端ID之外的任何内容。如果有人能指出我在正确的方向，我正试图建立一个更安全的应用程序使用服务帐户。

Credentials credentials = GoogleCredentials.fromStream(new FileInputStream(SERVICE_ACCOUNT_JSON_PATH));
this.storage = StorageOptions.newBuilder().setCredentials(credentials)
.build().getService();

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.gmail.model.Label;
import com.google.api.services.gmail.model.ListLabelsResponse;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.GeneralSecurityException;
import java.util.Collections;
import java.util.List;
public class GmailQuickstart {
private static final String APPLICATION_NAME = "Gmail API Java Quickstart";
private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
private static final String TOKENS_DIRECTORY_PATH = "tokens";
/**
* Global instance of the scopes required by this quickstart.
* If modifying these scopes, delete your previously saved tokens/ folder.
*/
private static final List<String> SCOPES = Collections.singletonList(GmailScopes.GMAIL_LABELS);
private static final String CREDENTIALS_FILE_PATH = "/credentials.json";
/**
* Creates an authorized Credential object.
* @param HTTP_TRANSPORT The network HTTP Transport.
* @return An authorized Credential object.
* @throws IOException If the credentials.json file cannot be found.
*/
private static Credential getCredentials(final NetHttpTransport HTTP_TRANSPORT) throws IOException {
// Load client secrets.
InputStream in = GmailQuickstart.class.getResourceAsStream(CREDENTIALS_FILE_PATH);
if (in == null) {
throw new FileNotFoundException("Resource not found: " + CREDENTIALS_FILE_PATH);
}
GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(in));
// Build flow and trigger user authorization request.
GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
HTTP_TRANSPORT, JSON_FACTORY, clientSecrets, SCOPES)
.setDataStoreFactory(new FileDataStoreFactory(new java.io.File(TOKENS_DIRECTORY_PATH)))
.setAccessType("offline")
.build();
LocalServerReceiver receiver = new LocalServerReceiver.Builder().setPort(8888).build();
return new AuthorizationCodeInstalledApp(flow, receiver).authorize("user");
}
public static void main(String... args) throws IOException, GeneralSecurityException {
// Build a new authorized API client service.
final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
Gmail service = new Gmail.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredentials(HTTP_TRANSPORT))
.setApplicationName(APPLICATION_NAME)
.build();
// Print the labels in the user's account.
String user = "me";
ListLabelsResponse listResponse = service.users().labels().list(user).execute();
List<Label> labels = listResponse.getLabels();
if (labels.isEmpty()) {
System.out.println("No labels found.");
} else {
System.out.println("Labels:");
for (Label label : labels) {
System.out.printf("- %sn", label.getName());
}
}
}
}

Answer 1

为了使用服务帐户凭证，您必须调整您的代码以便使用它们，类似于:

private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
private static final String SERVICE_ACCOUNT_ID = "SERVICE_ACCOUNT_ID";
private static final String APPLICATION_NAME = "Gmail API Java Quickstart";
PrivateKey key = (PrivateKey)keystore.getKey(KEY.toCharArray()); 
HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
GoogleCredential credentials = new GoogleCredential.Builder()
.setTransport(httpTransport)
.setJsonFactory(JSON_FACTORY)
.setServiceAccountId(SERVICE_ACCOUNT_ID)
.setServiceAccountScopes(SCOPES)
.setServiceAccountPrivateKey(key)
.setServiceAccountEmail("SERVICE_ACCOUNT_ID")
.build();
Gmail service =  new Gmail.Builder(httpTransport, JSON_FACTORY, credentials)
.setApplicationName(APPLICATION_NAME).build();

但是，请记住，创建一个服务帐户是不够的—您还必须通过冒充域中的另一个用户来委托权限。

对于文档，这里的广泛指南可能对您的用例有帮助。

参考

• OAuth 2.0 for Server to Server application;

• OAuth Client Library for Java.