somod-chat-service/build/serverless/functions/wsNotifyMessage.js

Serverless Chat Service from SOMOD

import { DynamoDBClient, QueryCommand } from "@aws-sdk/client-dynamodb";
import { convertToAttr, unmarshall } from "@aws-sdk/util-dynamodb";
import { ApiGatewayManagementApiClient, PostToConnectionCommand } from "@aws-sdk/client-apigatewaymanagementapi";
const dynamodb = new DynamoDBClient();
const apiGwManagementApi = new ApiGatewayManagementApiClient({
    endpoint: process.env.CONNECTIONS_ENDPOINT
});
const notifyMessage = async (connectionId, message) => {
    const data = JSON.stringify(message);
    try {
        await apiGwManagementApi.send(new PostToConnectionCommand({ ConnectionId: connectionId, Data: data }));
    }
    catch (e) {
        // eslint-disable-next-line no-console
        console.error(e);
    }
};
const WebsocketNotifyMessage = async (event) => {
    const userId = event.Records[0]?.Sns.MessageAttributes["userId"]?.Value;
    const message = JSON.parse(event.Records[0]?.Sns.Message);
    if (userId && message) {
        const connections = await dynamodb.send(new QueryCommand({
            TableName: process.env.CONNECTIONS_TABLE_NAME + "",
            IndexName: "ByUserId",
            KeyConditionExpression: "#userId = :userId",
            ExpressionAttributeNames: {
                "#userId": "userId"
            },
            ExpressionAttributeValues: {
                ":userId": convertToAttr(userId)
            }
        }));
        await Promise.all((connections.Items || []).map(async (item) => {
            const conn = unmarshall(item);
            await notifyMessage(conn.id, message);
        }));
    }
};
export default WebsocketNotifyMessage;