google-cloud-platform - 如何使用 JAVA 使用 REST API 从服务帐户凭据创建访问令牌？

Question

我需要在不使用 GCP Java 客户端库的情况下使用服务帐户凭据列出文件夹。我需要使用 REST API 调用，因为使用 GCP Java 客户端库有限制。是否有任何示例或示例可以参考在 Java/Spring 中进行 REST API 调用？

标签： google-cloud-platformgoogle-cloud-resource-manager

Answer 1

您可以使用 RestTemplate 和这个依赖

        <dependency>
            <groupId>com.auth0</groupId>
            <artifactId>java-jwt</artifactId>
            <version>3.14.0</version>
        </dependency>

然后，阅读您的服务帐户 JSON 文件（这里是我的key.json文件），尽情享受吧！如果某些部分不清楚，请告诉我！

        InputStream resource = new ClassPathResource("key.json").getInputStream();

        BufferedReader reader = new BufferedReader(new InputStreamReader(resource));
        String keyFileJson = reader.lines().collect(Collectors.joining("\n"));
        Map keyFile = new ObjectMapper().readValue(keyFileJson, Map.class);


        String privKeyPEM = keyFile.get("private_key").toString().replace("-----BEGIN PRIVATE KEY-----","")
                .replace("-----END PRIVATE KEY-----","")
                .replaceAll("\n","");

        byte [] encoded = Base64.decode(privKeyPEM);

        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        PrivateKey privKey = kf.generatePrivate(keySpec);

        String tokenUrl = "https://oauth2.googleapis.com/token";

        long now = System.currentTimeMillis();
        Algorithm algorithm = Algorithm.RSA256(null, (RSAPrivateKey)privKey);
        String signedJwt = JWT.create()
                .withKeyId(keyFile.get("private_key_id").toString())
                .withIssuer(keyFile.get("client_email").toString())
                .withAudience(tokenUrl)
                .withClaim("scope","openid https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/appengine.admin https://www.googleapis.com/auth/compute")
                .withIssuedAt(new Date(now))
                .withExpiresAt(new Date(now + 3600 * 1000L))
                .sign(algorithm);
//        System.out.println(signedJwt);


        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

        MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
        map.add("assertion", signedJwt);
        map.add("grant_type", "urn:ietf:params:oauth:grant-type:jwt-bearer");

        HttpEntity<MultiValueMap<String, String>> entity = new HttpEntity<>(map, headers);
        ResponseEntity<String> responseEntity = restTemplate.postForEntity(tokenUrl, entity, String.class);
        Map result = new ObjectMapper().readValue(responseEntity.getBody(), Map.class);
        System.out.println(result.get("access_token"));

---

编辑 1

要生成和获取 ID_Token，如果您要生成令牌以调用以安全模式部署的 Cloud Run、Cloud Functions 或 App Engine，则需要此选项。您需要用 target_audience URL 替换范围声明。最后，打印 id_token 而不是访问令牌

        String signedJwt = JWT.create()
                .withKeyId(keyFile.get("private_key_id").toString())
                .withIssuer(keyFile.get("client_email").toString())
                .withAudience(tokenUrl)
                .withClaim("target_audience", "https://target-log-fqffbf2xsq-uc.a.run.app")
                .withIssuedAt(new Date(now))
                .withExpiresAt(new Date(now + 3600 * 1000L))
                .sign(algorithm);

...
...
...
System.out.println(result.get("id_token"));