问题描述

使用中国区的Azure，在获取Token时候，参考了 adal4j的代码，在官方文档中，发现了如下的片段代码：

ExecutorService service = Executors.newFixedThreadPool(1);
AuthenticationContext context = new AuthenticationContext(AUTHORITY, false, service);
Future<AuthenticationResult> future = context.acquireToken(
    "https://graph.windows.net", YOUR_TENANT_ID, username, password,
    null);
AuthenticationResult result = future.get();
System.out.println("Access Token - " + result.getAccessToken());
System.out.println("Refresh Token - " + result.getRefreshToken());
System.out.println("ID Token - " + result.getIdToken());

以上代码中，有一些参数很不明确：

1）AUTHORITY, 是什么意思呢？
2）acquireTokne方法中的 https://graph.windows.net 是指向global azure的资源，如果是中国区azure的资源，那么resource url是多少呢？
3）YOUR_TENANT_ID，它的值是什么呢？

问题解答

第一个问题：AUTHORITY, 是什么意思，它的值是什么呢？

AUTHORITY，表示认证的主体，它是一个URL，表示可以从该主体中获取到认证Token。它的格式为：https://<authority host>/<tenant id> ，所以在使用Azure的过程中，根据Azure环境的不同，Host 有以下四个值。

AzureChina :The host of the Azure Active Directory authority for tenants in the Azure China Cloud. AZURE_CHINA = "login.chinacloudapi.cn"
AzureGermany: The host of the Azure Active Directory authority for tenants in the Azure German Cloud. AZURE_GERMANY = "login.microsoftonline.de"
AzureGovernment: The host of the Azure Active Directory authority for tenants in the Azure US Government Cloud. AZURE_GOVERNMENT = "login.microsoftonline.us"
AzurePublicCloud: The host of the Azure Active Directory authority for tenants in the Azure Public Cloud. AZURE_PUBLIC_CLOUD = "login.microsoftonline.com"

所以，这里我们需要使用的值为：String AUTHORITY = "https://login.chinacloudapi.cn/<tenant id >";

那么如何来获取Tenant ID呢？

登录到Azure门户 --> 进入AAD中，在Overview页面查看Tenant ID (https://portal.azure.cn/#blade/Microsoft_AAD_IAM/ActiveDirectoryMenuBlade/Overview)

image.png

第二个问题：acquireTokne方法中的 https://graph.windows.net 是指向global azure的资源，如果是中国区azure的资源，那么resource url是多少呢？

根据中国区Azure的开发文档，并没有查找到对应于 graph.windows.net的中国区Graph 终结点。但是，中国区Graph 的终结点为：microsoftgraph.chinacloudapi.cn，所以，以上示例中应该使用的值应是：

https://microsoftgraph.chinacloudapi.cn/

image.png

(Source: https://docs.microsoft.com/en-us/azure/china/resources-developer-guide#check-endpoints-in-azure)

第三个问题：YOUR_TENANT_ID，它的值是什么呢？

在对比了adal4j的源代码后，在acquireToken方法定义中，发现YOUR_TENANT_ID所对应的值应该是 clientId ()。所以，官网参考文档中的YOUR_TENANT_ID存在误导情景。需要修改为YOUR_CLIENT_ID。

ADAL4J中acquireToken源码(acquireToken有多个重载，但此处只列举出代码中使用的这个重载)

    /**
     * Acquires a security token from the authority using a Refresh Token
     * previously received.
     *
     * @param clientId
     *            Name or ID of the client requesting the token.
     * @param resource
     *            Identifier of the target resource that is the recipient of the
     *            requested token. If null, token is requested for the same
     *            resource refresh token was originally issued for. If passed,
     *            resource should match the original resource used to acquire
     *            refresh token unless token service supports refresh token for
     *            multiple resources.
     * @param username
     *            Username of the managed or federated user.
     * @param password
     *            Password of the managed or federated user.
     * @param callback
     *            optional callback object for non-blocking execution.
     * @return A {@link Future} object representing the
     *         {@link AuthenticationResult} of the call. It contains Access
     *         Token, Refresh Token and the Access Token's expiration time.
     */
    public Future<AuthenticationResult> acquireToken(final String resource,
            final String clientId, final String username,
            final String password, final AuthenticationCallback callback) {
        if (StringHelper.isBlank(resource)) {
            throw new IllegalArgumentException("resource is null or empty");
        }

        if (StringHelper.isBlank(clientId)) {
            throw new IllegalArgumentException("clientId is null or empty");
        }

        if (StringHelper.isBlank(username)) {
            throw new IllegalArgumentException("username is null or empty");
        }

        if (StringHelper.isBlank(password)) {
            throw new IllegalArgumentException("password is null or empty");
        }

        return this.acquireToken(new AdalAuthorizatonGrant(
                new ResourceOwnerPasswordCredentialsGrant(username, new Secret(
                        password)), resource), new ClientAuthenticationPost(
                ClientAuthenticationMethod.NONE, new ClientID(clientId)),
                callback);
    }

所以，这里指定的Client ID 其实是，AAD中所注册的一个应用(服务主体)，而这个主体可以根据需求授予不同的权限，acquireToken就是根据用户验证成功后，生成这个主题所拥有的权限JWT令牌(Token)，获取到Token后，就拥有了访问Azure中资源API的授权.

如何来获取这个Client ID呢？

进入AAD, 选择注册应用( App Registrations：https://portal.azure.cn/#blade/Microsoft_AAD_IAM/ActiveDirectoryMenuBlade/RegisteredApps)
并在Onwed Applications 中选择，进入详细页面或就是当前页面，获取Application(Client) ID

image.png

特别注意：这个App必须开启 “Allow public client flows“ 才能成功获取到 Token。默认情况下，这里选择的是No。如果不开启这一步，将会收到错误消息："error_description":"AADSTS7000218: The request body must contain the following parameter: 'client_assertion' or 'client_secret'.

开启方式为：点击这个App的名称，进入详细页面，选择Authentication，滑动到最底部，选择“Allow public client flows”。

image.png

完成参考实例代码

1:在POM.XML文件中添加adal4j依赖

<dependency>
<groupId>com.microsoft.azure</groupId>
<artifactId>adal4j</artifactId>
<version>1.2.0</version>
</dependency>

2：示例代码

package com.example; 
import java.net.MalformedURLException; 
import java.util.concurrent.ExecutionException; 
import java.util.concurrent.ExecutorService; 
import java.util.concurrent.Executors; 
import java.util.concurrent.Future; 
import com.microsoft.aad.adal4j.AuthenticationContext; 
import com.microsoft.aad.adal4j.AuthenticationResult; 
/** * Hello world!
 * */
public class App { public static void main(String[] args) throws InterruptedException, ExecutionException, MalformedURLException {
        System.out.println("Hello World!");

        ExecutorService service = Executors.newFixedThreadPool(1);
        String AUTHORITY = "https://login.chinacloudapi.cn/<tenant id >"; // AzureAuthority 
 String YOUR_Client_ID="7b61c392-xxxx-xxxx-xxxx-xxxxxxxxxxx";
        String username = "xxxx@xxxx.xxx.onmschina.cn";
        String password = "xxxxxxxxxxx";
        AuthenticationContext context = new AuthenticationContext(AUTHORITY, false, service);
        Future<AuthenticationResult> future = context.acquireToken("https://microsoftgraph.chinacloudapi.cn/", YOUR_Client_ID,
                username, password, null);
        AuthenticationResult result = future.get();

        System.out.println("Access Token - " + result.getAccessToken());
        System.out.println("Refresh Token - " + result.getRefreshToken());
        System.out.println("ID Token - " + result.getIdToken());

    }
}

（PS: 使用的 username， password就是登录Azure的用户名和密码）

测试结果：

image.png

获取Token成功。
可以通过一个公用网站 jwt.io 来解析Token： https://jwt.io/, 它可以解析出Token内容，让我们可读。

image.png

参考资料

Azure China developer guide：https://docs.microsoft.com/en-us/azure/china/resources-developer-guide#check-endpoints-in-azure

Authority: https://docs.microsoft.com/en-us/azure/active-directory/develop/msal-client-application-configuration#authority

Authority Value: [https://azuresdkdocs.blob.core.windows.net/ $web/python/azure-identity/1.4.0/_modules/azure/identity/_constants.html#AzureAuthorityHosts](https://azuresdkdocs.blob.core.windows.net/$ web/python/azure-identity/1.4.0/_modules/azure/identity/_constants.html#AzureAuthorityHosts)