Amazon S3 アクセス許可の管理 - AWS SDK for C++
前提条件オブジェクトのアクセスコントロールリストを管理するバケットのアクセスコントロールリストを管理する

Amazon S3 アクセス許可の管理

Amazon S3 バケットまたはオブジェクトのアクセス許可は、アクセスコントロールリスト (ACL) で定義されます。ACL では、バケット/オブジェクトの所有者、およびアクセス許可付与設定の一覧を指定します。アクセス許可付与設定では、ユーザー (被付与者) と、バケット/オブジェクトに対してそのユーザーに付与するアクセス許可 (READ や WRITE など) を指定します。

前提条件

作業を始める前に「AWS SDK for C++ の開始方法」を読むことをお勧めします。

コード例をダウンロードし、「コード例の開始方法」の説明に従ってソリューションをビルドします。

例を実行するには、リクエストに使用するユーザープロファイルに、AWS のサービスとアクションに対する適切なアクセス許可が付与されている必要があります。詳細については、「AWS 認証情報の提供」を参照してください。

オブジェクトのアクセスコントロールリストを管理する

オブジェクトのアクセスコントロールリストは S3Client メソッド GetObjectAcl を呼び出すことで取得できます。メソッドは、オブジェクトとそのバケットの名前を受け入れます。戻り値には ACL の Owner、およびGrants の一覧が含まれます。

bool AwsDoc::S3::getObjectAcl(const Aws::String &bucketName,
                              const Aws::String &objectKey,
                              const Aws::S3::S3ClientConfiguration &clientConfig) {
    Aws::S3::S3Client s3Client(clientConfig);

    Aws::S3::Model::GetObjectAclRequest request;
    request.SetBucket(bucketName);
    request.SetKey(objectKey);

    Aws::S3::Model::GetObjectAclOutcome outcome =
            s3Client.GetObjectAcl(request);

    if (!outcome.IsSuccess()) {
        const Aws::S3::S3Error &err = outcome.GetError();
        std::cerr << "Error: getObjectAcl: "
                  << err.GetExceptionName() << ": " << err.GetMessage() << std::endl;
    } else {
        Aws::Vector<Aws::S3::Model::Grant> grants =
                outcome.GetResult().GetGrants();

        for (auto it = grants.begin(); it != grants.end(); it++) {
            std::cout << "For object " << objectKey << ": "
                      << std::endl << std::endl;

            Aws::S3::Model::Grant grant = *it;
            Aws::S3::Model::Grantee grantee = grant.GetGrantee();

            if (grantee.TypeHasBeenSet()) {
                std::cout << "Type:          "
                          << getGranteeTypeString(grantee.GetType()) << std::endl;
            }

            if (grantee.DisplayNameHasBeenSet()) {
                std::cout << "Display name:  "
                          << grantee.GetDisplayName() << std::endl;
            }

            if (grantee.EmailAddressHasBeenSet()) {
                std::cout << "Email address: "
                          << grantee.GetEmailAddress() << std::endl;
            }

            if (grantee.IDHasBeenSet()) {
                std::cout << "ID:            "
                          << grantee.GetID() << std::endl;
            }

            if (grantee.URIHasBeenSet()) {
                std::cout << "URI:           "
                          << grantee.GetURI() << std::endl;
            }

            std::cout << "Permission:    " <<
                      getPermissionString(grant.GetPermission()) <<
                      std::endl << std::endl;
        }
    }

    return outcome.IsSuccess();
}

//! Routine which converts a built-in type enumeration to a human-readable string.
/*!
 \param type: Type enumeration.
 \return String: Human-readable string
*/
Aws::String getGranteeTypeString(const Aws::S3::Model::Type &type) {
    switch (type) {
        case Aws::S3::Model::Type::AmazonCustomerByEmail:
            return "Email address of an AWS account";
        case Aws::S3::Model::Type::CanonicalUser:
            return "Canonical user ID of an AWS account";
        case Aws::S3::Model::Type::Group:
            return "Predefined Amazon S3 group";
        case Aws::S3::Model::Type::NOT_SET:
            return "Not set";
        default:
            return "Type unknown";
    }
}

//! Routine which converts a built-in type enumeration to a human-readable string.
/*!
 \param permission: Permission enumeration.
 \return String: Human-readable string
*/
Aws::String getPermissionString(const Aws::S3::Model::Permission &permission) {
    switch (permission) {
        case Aws::S3::Model::Permission::FULL_CONTROL:
            return "Can read this object's data and its metadata, "
                   "and read/write this object's permissions";
        case Aws::S3::Model::Permission::NOT_SET:
            return "Permission not set";
        case Aws::S3::Model::Permission::READ:
            return "Can read this object's data and its metadata";
        case Aws::S3::Model::Permission::READ_ACP:
            return "Can read this object's permissions";
            // case Aws::S3::Model::Permission::WRITE // Not applicable.
        case Aws::S3::Model::Permission::WRITE_ACP:
            return "Can write this object's permissions";
        default:
            return "Permission unknown";
    }
}

ACL は、新規に作成するか、既存の ACL のアクセス許可付与設定を編集することで変更できます。更新された ACL は、PutObjectAcl メソッドに渡すことで新しい現在の ACL になります。

次のコードでは、GetObjectAcl で取得した ACL に新しいアクセス許可付与設定を追加しています。ユーザー (被付与者) には、オブジェクトに対する READ アクセス許可が付与されます。変更された ACL は PutObjectAcl に渡され、新たな ACL として適用されます。

bool AwsDoc::S3::putObjectAcl(const Aws::String &bucketName, const Aws::String &objectKey, const Aws::String &ownerID,
                              const Aws::String &granteePermission, const Aws::String &granteeType,
                              const Aws::String &granteeID, const Aws::String &granteeEmailAddress,
                              const Aws::String &granteeURI, const Aws::S3::S3ClientConfiguration &clientConfig) {
    Aws::S3::S3Client s3Client(clientConfig);

    Aws::S3::Model::Owner owner;
    owner.SetID(ownerID);

    Aws::S3::Model::Grantee grantee;
    grantee.SetType(setGranteeType(granteeType));

    if (!granteeEmailAddress.empty()) {
        grantee.SetEmailAddress(granteeEmailAddress);
    }

    if (!granteeID.empty()) {
        grantee.SetID(granteeID);
    }

    if (!granteeURI.empty()) {
        grantee.SetURI(granteeURI);
    }

    Aws::S3::Model::Grant grant;
    grant.SetGrantee(grantee);
    grant.SetPermission(setGranteePermission(granteePermission));

    Aws::Vector<Aws::S3::Model::Grant> grants;
    grants.push_back(grant);

    Aws::S3::Model::AccessControlPolicy acp;
    acp.SetOwner(owner);
    acp.SetGrants(grants);

    Aws::S3::Model::PutObjectAclRequest request;
    request.SetAccessControlPolicy(acp);
    request.SetBucket(bucketName);
    request.SetKey(objectKey);

    Aws::S3::Model::PutObjectAclOutcome outcome =
            s3Client.PutObjectAcl(request);

    if (!outcome.IsSuccess()) {
        auto error = outcome.GetError();
        std::cerr << "Error: putObjectAcl: " << error.GetExceptionName()
                  << " - " << error.GetMessage() << std::endl;
    } else {
        std::cout << "Successfully added an ACL to the object '" << objectKey
                  << "' in the bucket '" << bucketName << "'." << std::endl;
    }

    return outcome.IsSuccess();
}

//! Routine which converts a human-readable string to a built-in type enumeration.
/*!
 \param access: Human readable string.
 \return Permission: Permission enumeration.
*/
Aws::S3::Model::Permission setGranteePermission(const Aws::String &access) {
    if (access == "FULL_CONTROL")
        return Aws::S3::Model::Permission::FULL_CONTROL;
    if (access == "WRITE")
        return Aws::S3::Model::Permission::WRITE;
    if (access == "READ")
        return Aws::S3::Model::Permission::READ;
    if (access == "WRITE_ACP")
        return Aws::S3::Model::Permission::WRITE_ACP;
    if (access == "READ_ACP")
        return Aws::S3::Model::Permission::READ_ACP;
    return Aws::S3::Model::Permission::NOT_SET;
}

//! Routine which converts a human-readable string to a built-in type enumeration.
/*!
 \param type: Human readable string.
 \return Type: Type enumeration.
*/
Aws::S3::Model::Type setGranteeType(const Aws::String &type) {
    if (type == "Amazon customer by email")
        return Aws::S3::Model::Type::AmazonCustomerByEmail;
    if (type == "Canonical user")
        return Aws::S3::Model::Type::CanonicalUser;
    if (type == "Group")
        return Aws::S3::Model::Type::Group;
    return Aws::S3::Model::Type::NOT_SET;
}

GitHub で完全な例をご覧ください。

バケットのアクセスコントロールリストを管理する

多くの場合、バケットに対するアクセス許可を設定するには、バケットポリシーを定義することをお勧めします。ただし、希望すればバケットに対してアクセスコントロールリストを使用することも可能です。

バケットに対するアクセスコントロールリストの管理は、オブジェクトに使用されるものと同じです。GetBucketAcl メソッドでバケットの現在の ACL を取得し、PutBucketAcl メソッドで新しい ACL をバケットに適用します。

次のコードでは、バケットに対する ACL の取得および設定方法を示しています。


//! Routine which demonstrates setting the ACL for an S3 bucket.
/*!
  \param bucketName: Name of a bucket.
  \param ownerID: The canonical ID of the bucket owner.
   See https://docs.aws.amazon.com/AmazonS3/latest/userguide/finding-canonical-user-id.html for more information.
  \param granteePermission: The access level to enable for the grantee.
  \param granteeType: The type of grantee.
  \param granteeID: The canonical ID of the grantee.
  \param granteeEmailAddress: The email address associated with the grantee's AWS account.
  \param granteeURI: The URI of a built-in access group.
  \param clientConfig: Aws client configuration.
  \return bool: Function succeeded.
*/

bool AwsDoc::S3::getPutBucketAcl(const Aws::String &bucketName,
                                 const Aws::String &ownerID,
                                 const Aws::String &granteePermission,
                                 const Aws::String &granteeType,
                                 const Aws::String &granteeID,
                                 const Aws::String &granteeEmailAddress,
                                 const Aws::String &granteeURI,
                                 const Aws::S3::S3ClientConfiguration &clientConfig) {
    bool result = ::putBucketAcl(bucketName, ownerID, granteePermission, granteeType,
                                 granteeID,
                                 granteeEmailAddress,
                                 granteeURI,
                                 clientConfig);
    if (result) {
        result = ::getBucketAcl(bucketName, clientConfig);
    }

    return result;
}

//! Routine which demonstrates setting the ACL for an S3 bucket.
/*!
  \param bucketName: Name of from bucket.
  \param ownerID: The canonical ID of the bucket owner.
   See https://docs.aws.amazon.com/AmazonS3/latest/userguide/finding-canonical-user-id.html for more information.
  \param granteePermission: The access level to enable for the grantee.
  \param granteeType: The type of grantee.
  \param granteeID: The canonical ID of the grantee.
  \param granteeEmailAddress: The email address associated with the grantee's AWS account.
  \param granteeURI: The URI of a built-in access group.
  \param clientConfig: Aws client configuration.
  \return bool: Function succeeded.
*/

bool putBucketAcl(const Aws::String &bucketName,
                  const Aws::String &ownerID,
                  const Aws::String &granteePermission,
                  const Aws::String &granteeType,
                  const Aws::String &granteeID,
                  const Aws::String &granteeEmailAddress,
                  const Aws::String &granteeURI,
                  const Aws::S3::S3ClientConfiguration &clientConfig) {
    Aws::S3::S3Client s3Client(clientConfig);

    Aws::S3::Model::Owner owner;
    owner.SetID(ownerID);

    Aws::S3::Model::Grantee grantee;
    grantee.SetType(setGranteeType(granteeType));

    if (!granteeEmailAddress.empty()) {
        grantee.SetEmailAddress(granteeEmailAddress);
    }

    if (!granteeID.empty()) {
        grantee.SetID(granteeID);
    }

    if (!granteeURI.empty()) {
        grantee.SetURI(granteeURI);
    }

    Aws::S3::Model::Grant grant;
    grant.SetGrantee(grantee);
    grant.SetPermission(setGranteePermission(granteePermission));

    Aws::Vector<Aws::S3::Model::Grant> grants;
    grants.push_back(grant);

    Aws::S3::Model::AccessControlPolicy acp;
    acp.SetOwner(owner);
    acp.SetGrants(grants);

    Aws::S3::Model::PutBucketAclRequest request;
    request.SetAccessControlPolicy(acp);
    request.SetBucket(bucketName);

    Aws::S3::Model::PutBucketAclOutcome outcome =
            s3Client.PutBucketAcl(request);

    if (!outcome.IsSuccess()) {
        const Aws::S3::S3Error &error = outcome.GetError();

        std::cerr << "Error: putBucketAcl: " << error.GetExceptionName()
                  << " - " << error.GetMessage() << std::endl;
    } else {
        std::cout << "Successfully added an ACL to the bucket '" << bucketName
                  << "'." << std::endl;
    }

    return outcome.IsSuccess();
}

//! Routine which demonstrates getting the ACL for an S3 bucket.
/*!
  \param bucketName: Name of the s3 bucket.
  \param clientConfig: Aws client configuration.
  \return bool: Function succeeded.
*/
bool getBucketAcl(const Aws::String &bucketName,
                  const Aws::S3::S3ClientConfiguration &clientConfig) {
    Aws::S3::S3Client s3Client(clientConfig);

    Aws::S3::Model::GetBucketAclRequest request;
    request.SetBucket(bucketName);

    Aws::S3::Model::GetBucketAclOutcome outcome =
            s3Client.GetBucketAcl(request);

    if (!outcome.IsSuccess()) {
        const Aws::S3::S3Error &err = outcome.GetError();
        std::cerr << "Error: getBucketAcl: "
                  << err.GetExceptionName() << ": " << err.GetMessage() << std::endl;
    } else {
        const Aws::Vector<Aws::S3::Model::Grant> &grants =
                outcome.GetResult().GetGrants();

        for (const Aws::S3::Model::Grant &grant: grants) {
            const Aws::S3::Model::Grantee &grantee = grant.GetGrantee();

            std::cout << "For bucket " << bucketName << ": "
                      << std::endl << std::endl;

            if (grantee.TypeHasBeenSet()) {
                std::cout << "Type:          "
                          << getGranteeTypeString(grantee.GetType()) << std::endl;
            }

            if (grantee.DisplayNameHasBeenSet()) {
                std::cout << "Display name:  "
                          << grantee.GetDisplayName() << std::endl;
            }

            if (grantee.EmailAddressHasBeenSet()) {
                std::cout << "Email address: "
                          << grantee.GetEmailAddress() << std::endl;
            }

            if (grantee.IDHasBeenSet()) {
                std::cout << "ID:            "
                          << grantee.GetID() << std::endl;
            }

            if (grantee.URIHasBeenSet()) {
                std::cout << "URI:           "
                          << grantee.GetURI() << std::endl;
            }

            std::cout << "Permission:    " <<
                      getPermissionString(grant.GetPermission()) <<
                      std::endl << std::endl;
        }
    }

    return outcome.IsSuccess();
}

//! Routine which converts a built-in type enumeration to a human-readable string.
/*!
 \param permission: Permission enumeration.
 \return String: Human-readable string.
*/

Aws::String getPermissionString(const Aws::S3::Model::Permission &permission) {
    switch (permission) {
        case Aws::S3::Model::Permission::FULL_CONTROL:
            return "Can list objects in this bucket, create/overwrite/delete "
                   "objects in this bucket, and read/write this "
                   "bucket's permissions";
        case Aws::S3::Model::Permission::NOT_SET:
            return "Permission not set";
        case Aws::S3::Model::Permission::READ:
            return "Can list objects in this bucket";
        case Aws::S3::Model::Permission::READ_ACP:
            return "Can read this bucket's permissions";
        case Aws::S3::Model::Permission::WRITE:
            return "Can create, overwrite, and delete objects in this bucket";
        case Aws::S3::Model::Permission::WRITE_ACP:
            return "Can write this bucket's permissions";
        default:
            return "Permission unknown";
    }
}

//! Routine which converts a human-readable string to a built-in type enumeration
/*!
 \param access: Human readable string.
 \return Permission: Permission enumeration.
*/
Aws::S3::Model::Permission setGranteePermission(const Aws::String &access) {
    if (access == "FULL_CONTROL")
        return Aws::S3::Model::Permission::FULL_CONTROL;
    if (access == "WRITE")
        return Aws::S3::Model::Permission::WRITE;
    if (access == "READ")
        return Aws::S3::Model::Permission::READ;
    if (access == "WRITE_ACP")
        return Aws::S3::Model::Permission::WRITE_ACP;
    if (access == "READ_ACP")
        return Aws::S3::Model::Permission::READ_ACP;
    return Aws::S3::Model::Permission::NOT_SET;
}

//! Routine which converts a built-in type enumeration to a human-readable string.
/*!
 \param type: Type enumeration.
 \return bool: Human-readable string.
*/
Aws::String getGranteeTypeString(const Aws::S3::Model::Type &type) {
    switch (type) {
        case Aws::S3::Model::Type::AmazonCustomerByEmail:
            return "Email address of an AWS account";
        case Aws::S3::Model::Type::CanonicalUser:
            return "Canonical user ID of an AWS account";
        case Aws::S3::Model::Type::Group:
            return "Predefined Amazon S3 group";
        case Aws::S3::Model::Type::NOT_SET:
            return "Not set";
        default:
            return "Type unknown";
    }
}

Aws::S3::Model::Type setGranteeType(const Aws::String &type) {
    if (type == "Amazon customer by email")
        return Aws::S3::Model::Type::AmazonCustomerByEmail;
    if (type == "Canonical user")
        return Aws::S3::Model::Type::CanonicalUser;
    if (type == "Group")
        return Aws::S3::Model::Type::Group;
    return Aws::S3::Model::Type::NOT_SET;
}

GitHub で完全な例をご覧ください。