Identity as a Service：Java 應用接入賬戶同步樣本

本篇文檔以 Java 為例，講解作為應用與 IDaaS 的對接。

若您希望瞭解對接原理和調用流程，請參考 賬戶同步接入概述。

接入賬戶同步可能需要處理兩點：

• 驗簽

• 解密（可選）

進行完上述過程後，即可擷取到該次事件的請求內容，應用自行處理即可。

1. 驗簽

參考 賬戶同步 - IDaaS 同步到應用 中操作，從應用同步配置中擷取公開金鑰端點。

在本文檔樣本中，提供了直接從公開金鑰端點擷取公開金鑰的 Java 工具類。若您所選開發語言需要公開金鑰資訊，可能需要您點開公開金鑰端點，擷取公開金鑰內容，轉化成 .pem 檔案格式儲存在本地。

公開金鑰樣本：

{
  "keys": [
    {
      "kty": "RSA",
      "e": "AQAB",
      "use": "sig",
      "kid": "KEY3PdQDx97********h83p8husNSC9AKMH",
      "n": "rLUnH5PNeGUZE-********GGIxyM5O7TDdaG4********D9mV1CjE8hVHBxXM96IcCCH_1xmUZEZRp_MBP6m2XeNWUXanCpeyuIAD2kxmaQAqituZdIlT4l3-q9gtccdY-khaE-OfH9qYZhlxFcYj0gVtOvKZFIkuGhME4IQJd_RAWS3OPXxtbGhO2fZYCiuuc8NWub5mcVQnqsy5aJPLwHbVwVUwYNOmaq97_m2TtPcIVWtw7AOzX8O78UrYnYt_QPrv7uVdJMbHleSOx2A1IXqrAkJWecwFfvTsBTCUOPPDeVRQEHzzwmf3zpz5KMgHZU1I5pyqi0KJ6BuMHWw"
    }
  ]
}

添加 Maven 依賴：

<dependency>
  <groupId>org.bitbucket.b_c</groupId>
  <artifactId>jose4j</artifactId>
  <version>0.7.9</version>
</dependency>

工具類代碼如下，用於從 IDaaS 公開金鑰端點擷取公開金鑰並驗簽，您可以直接複製使用：

import org.apache.commons.codec.binary.StringUtils;
import org.jose4j.jwk.JsonWebKey;
import org.jose4j.jwk.JsonWebKeySet;
import org.jose4j.jwt.consumer.JwtConsumer;
import org.jose4j.jwt.consumer.JwtConsumerBuilder;
import org.jose4j.lang.JoseException;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

public class JwtUtil {
    private final static ConcurrentMap<String, JsonWebKeySet> IDAAS_SIGN_JWK_SET_MAP = new ConcurrentHashMap<>();

    public static JwtConsumer createJwtConsumerFromUrl(String jwkUrl, String appId) {
        try {
            final JsonWebKeySet jsonWebKeySet = getJsonWebKeySetByUrl(jwkUrl);
            return createJwtConsumer(jsonWebKeySet, appId);
        } catch (Exception e) {
            throw new RuntimeException("Fetch JWKs from url failed: " + e.getMessage() + ", " + jwkUrl, e);
        }
    }

    public static JwtConsumer createJwtConsumer(JsonWebKeySet jsonWebKeySet, String appId) {
        final JwtConsumerBuilder jwtConsumerBuilder = new JwtConsumerBuilder();
        jwtConsumerBuilder.setExpectedIssuer("urn:alibaba:idaas:app:event");
        jwtConsumerBuilder.setRequireExpirationTime();
        jwtConsumerBuilder.setRequireJwtId();
        jwtConsumerBuilder.setRequireIssuedAt();
        jwtConsumerBuilder.setRequireExpirationTime();
        jwtConsumerBuilder.setMaxFutureValidityInMinutes(1);
        jwtConsumerBuilder.setAllowedClockSkewInSeconds(120);
        jwtConsumerBuilder.setExpectedAudience(appId);
        jwtConsumerBuilder.setVerificationKeyResolver((jws, nestingContext) -> {
            final String signKeyId = jws.getKeyIdHeaderValue();
            for (JsonWebKey jsonWebKey : jsonWebKeySet.getJsonWebKeys()) {
                if (StringUtils.equals(jsonWebKey.getKeyId(), signKeyId)) {
                    return jsonWebKey.getKey();
                }
            }
            throw new RuntimeException("Cannot find verification key: " + signKeyId);
        });
        return jwtConsumerBuilder.build();
    }

    synchronized private static JsonWebKeySet getJsonWebKeySetByUrl(String jwkUrlString) throws IOException, JoseException {
        JsonWebKeySet jsonWebKeySet = IDAAS_SIGN_JWK_SET_MAP.get(jwkUrlString);
        if (jsonWebKeySet == null) {
            jsonWebKeySet = innerGetJsonWebKeySetByUrl(jwkUrlString);
            IDAAS_SIGN_JWK_SET_MAP.put(jwkUrlString, jsonWebKeySet);
        }
        return jsonWebKeySet;
    }

    private static JsonWebKeySet innerGetJsonWebKeySetByUrl(String jwkUrlString) throws IOException, JoseException {
        final URL jwkUrl = new URL(jwkUrlString);
        final URLConnection urlConnection = jwkUrl.openConnection();
        urlConnection.setConnectTimeout(50000);
        urlConnection.setReadTimeout(50000);
        final String jwkSetJson = new String(readAll(urlConnection.getInputStream()), StandardCharsets.UTF_8);
        return new JsonWebKeySet(jwkSetJson);
    }

    public static byte[] readAll(InputStream inputStream) throws IOException {
        final byte[] buffer = new byte[1024 * 8];
        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
        for (int len; ((len = inputStream.read(buffer)) != -1); ) {
            baos.write(buffer, 0, len);
        }
        return baos.toByteArray();
    }
}

調用範例程式碼：

//公開金鑰->IDaaS應用同步配置裡,訪問應用公開金鑰端點後擷取到。
String publicKey = "{\n"
            + "  \"keys\": [\n"
            + "    {\n"
            + "      \"kty\": \"RSA\",\n"
            + "      \"e\": \"AQAB\",\n"
            + "      \"use\": \"sig\",\n"
            + "      \"kid\": \"KEYHH4yFa1c*******qNo1nJ7nM2FR3595P1\",\n"
            + "      \"n\": \"oy_xxxxxxxxxxxxxxxxxxxxxxx95d1padSEABqIbcTKcnlTaET3WHaR"
            + "-3MvsooeZWluv94GQEp-U2jzM1adgTqBl_7KPjUk0dwrZbob_8pOLX5UQMF7Oo_nH5-H5EyL9-yGGhFA4oeuA"
            + "-b73qXShxP7eHs5xTT1kiYEu2NE3rBZdtrRwUiC_h1DvZMtyWFOPwm3dpLiwCcdlgcKvVuSEXyCBj6Gjevn3_G1guVQ2kHlNOVyNn6Ky1iGQJzXctJCEJ5fnBRs4XZZbPNSciYMD2-__cRdbYPtGyyuoEAfouw\"\n"
            + "    }\n"
            + "  ]\n"
            + "}";;

//應用ID->應用列表中，找到對應的應用ID
String appId = "app_mjavzivahje6zxxxx";
//JwtUtil->下面已提供JwtUtil工具類
JwtConsumer jwtConsumer = JwtUtil.createJwtConsumer(new JsonWebKeySet(publicKey),appId);

//JWT驗簽後，擷取到payload
//event參數值->介面接收到的參數值
JwtClaims jwtClaims = jwtConsumer.processToClaims("event參數的值");
//擷取到具體的payload
Map<String, Object> map = jwtClaims.getClaimsMap();
//接下來，根據具體的資料，做對應的業務處理

2. 解密（可選）

資料解密

若應用開啟業務資料加密，事件數目據將通過 cipher_data 加密傳遞，業務方需要解密，以擷取到同步資料。

IDaaS 支援自主填寫加密金鑰，也可由 IDaaS 產生。

將密鑰複製出來，解密時使用。

新增 Maven 依賴：

<dependency>
  <groupId>org.bitbucket.b_c</groupId>
  <artifactId>jose4j</artifactId>
  <version>0.7.9</version>
</dependency>
<dependency>
  <groupId>org.bouncycastle</groupId>
  <artifactId>bcprov-jdk15on</artifactId>
  <version>1.70</version>
</dependency>

解密範例程式碼：

public String decrypte(String cipherData,String key) throws JoseException {
    String alg = "AES";
    
    // 產生使用密鑰產生 KeySpec
    SecretKeySpec secretKeySpec = new SecretKeySpec(Hex.decode(key), alg);
    JsonWebKey jsonWebKey = JsonWebKey.Factory.newJwk(secretKeySpec);
    
    JsonWebEncryption receiverJwe = new JsonWebEncryption();
    
    // 設定加解密機制
    AlgorithmConstraints algConstraints = new AlgorithmConstraints(AlgorithmConstraints.ConstraintType.PERMIT, new String[]{"dir"});
    receiverJwe.setAlgorithmConstraints(algConstraints);
    
    AlgorithmConstraints encConstraints = new AlgorithmConstraints(
        AlgorithmConstraints.ConstraintType.PERMIT, new String[]{"A256GCM", "A192GCM", "A128GCM"});
    receiverJwe.setContentEncryptionAlgorithmConstraints(encConstraints);
    
    // 傳入密鑰和密文
    receiverJwe.setKey(jsonWebKey.getKey());
    receiverJwe.setCompactSerialization(cipherData);
    
    // 返回解密內容
    return new String(receiverJwe.getPlaintextBytes(), StandardCharsets.UTF_8);
}