【Amplify×Flutter】Lambdaを経由してPush通知を送信する方法

/*
  Pinpointにユーザーの情報を登録または更新する
  このコードを実行することで、アプリケーションのユーザー情報をAmazon Pinpointに識別および提供する。
*/
Future<void> addAnalyticsWithLocation(String userId, String email) async {
  final userProfile = UserProfile(
    email: email,
  );
  await Amplify.Analytics.identifyUser(
    userId: userId,
    userProfile: userProfile,
  );
}

import { PinpointClient, GetUserEndpointsCommand, UpdateEndpointCommand, SendMessagesCommand } from '@aws-sdk/client-pinpoint';

const applicationId = process.env.AWS_PINPOINT_PROJECT_ID;

/**
 * デバイスの種類に応じたメッセージ生成。以下の区分となる。
 * @param channelType チャンネルタイプ（APNS | GCM）
 * 1. iPhone: APNS
 * 2. Android: GCM
 */
const buildMessageConfiguration = (channelType, title, body) => {
  const messageConfig = {
    Action: 'OPEN_APP',
    Title: title,
    Body: body,
  };

  switch (channelType) {
    case 'APNS':
      return { APNSMessage: messageConfig };
    case 'GCM':
      return { GCMMessage: messageConfig };
    // 他のChannelTypeに対するメッセージ設定もこちらに追加
    default:
      return null;
  }
};

/**
 * AWS Pinpointのエンドポイントを取得する
 */
const getEndpoint = async (client, userId) => {
  const params = {
    ApplicationId: applicationId,
    UserId: userId
  };

  return await client.send(new GetUserEndpointsCommand(params));
};

/**
 * AWS Pinpointのエンドポイントを更新する
 */
const updateEndpoint = async (client, EndpointId, EndpointRequest) => {
  const updateParams = {
    ApplicationId: applicationId,
    EndpointId: EndpointId,
    EndpointRequest: EndpointRequest
  };

  return await client.send(new UpdateEndpointCommand(updateParams));
};

/**
 * デバイスにPush通知を送信する
 */
const sendPushNotification = async (client, channelType, title, body, address) => {
  const messageConfig = buildMessageConfiguration(channelType, title, body);
  if (!messageConfig) {
    throw new Error(`Unsupported ChannelType: ${channelType}`);
  }

  const pushInput = {
    ApplicationId: applicationId,
    MessageRequest: {
      Addresses: {
        [address]: {
          ChannelType: channelType,
        },
      },
      MessageConfiguration: messageConfig
    },
  };

  return await client.send(new SendMessagesCommand(pushInput));
};

const errorResponse = (err) => {
  console.log(err);
  return {
    statusCode: 500,
    body: JSON.stringify(err)
  };
};


export const handler = async (event) => {
  const requestBody = event.body;
  const client = new PinpointClient({ region: requestBody.region });

  try {
    switch (requestBody.action) {
      case 'getEndpoint':
        const result = await getEndpoint(client, requestBody.userId);
        return { statusCode: 200, body: JSON.stringify(result) };

      case 'updateEndpoint':
        const updateResult = await updateEndpoint(client, requestBody.EndpointId, requestBody.EndpointRequest);
        return { statusCode: 200, body: JSON.stringify(updateResult) };

      case 'sendPushNotification':
        const pushResponse = await sendPushNotification(client, requestBody.channelType, requestBody.title, requestBody.body, requestBody.address);
        return { statusCode: 200, body: JSON.stringify(pushResponse) };

      default:
        return { statusCode: 400, body: JSON.stringify({ message: 'Invalid action' }) };
    }
  } catch (err) {
    return errorResponse(err);
  }
};

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "PinpointPolicy",
            "Effect": "Allow",
            "Action": [
                "mobiletargeting:GetUserEndpoints",
                "mobiletargeting:UpdateEndpoint",
                "mobiletargeting:GetEndpoint",
                "mobiletargeting:SendMessages",
                "mobiletargeting:SendUsersMessages"
            ],
            "Resource": "arn:aws:mobiletargeting:*:136112039144:apps/*"
        }
    ]
}

Future<void> fetchCognitoAuthSession() async {
  try {
    final cognitoPlugin = Amplify.Auth.getPlugin(AmplifyAuthCognito.pluginKey);
    final result = await cognitoPlugin.fetchAuthSession();
    final identityId = result.identityIdResult.value;
    safePrint("Current user's identity ID: $identityId");
  } on AuthException catch (e) {
    safePrint('Error retrieving auth session: ${e.message}');
  }
}

dependencies:
  http: ^1.1.0

// AWS API エンドポインt
final host = 'xxx.execute-api.ap-northeast-1.amazonaws.com';
final path = 'xxxx';

/*
  AWSにHTTPリクエストを送信する共通処理
  @param body リクエストbody
*/
Future<Map<String, dynamic>> callAWSHttpMethod(
  Map<String, dynamic> body,
) async {
  // idTokenを取得
  final idToken = await fetchCognitoUserPoolTokens();
  // httpリクエストを送信
  http.Response response = await http.post(
    Uri.https(
      host,
      path,
    ),
    headers: {'Authorization': idToken},
    body: utf8.encode(json.encode(body)),
  );
  safePrint('Response body: ${response.body}');
  return json.decode(response.body);
}