@channel.io/be-user-chat-mcp/dist/services/dynamodb.service.js

Backend UserChat Model Context Protocol server for Channel.io

import { DynamoDBClient, GetItemCommand, QueryCommand, } from "@aws-sdk/client-dynamodb";
import { marshall, unmarshall, } from "@aws-sdk/util-dynamodb";
let client = null;
// Get or initialize the DynamoDB client (Lazy Singleton for stdio, per-request for HTTP)
function getClient(context) {
    // For HTTP transport, always create new client with context credentials
    if (context.awsRegion &&
        context.awsAccessKeyId &&
        context.awsSecretAccessKey) {
        return new DynamoDBClient({
            region: context.awsRegion,
            credentials: {
                accessKeyId: context.awsAccessKeyId,
                secretAccessKey: context.awsSecretAccessKey,
                ...(context.awsSessionToken && {
                    sessionToken: context.awsSessionToken,
                }),
            },
        });
    }
    // For stdio transport, use singleton with default credential provider chain
    // (when context has awsProfile but no direct credentials)
    if (client) {
        return client;
    }
    // Initialize client without explicit credentials
    // SDK will use the default credential provider chain
    // (Environment variables, ~/.aws/credentials, ~/.aws/config, IAM role, etc.)
    client = new DynamoDBClient({});
    console.error("Initialized DynamoDBClient using default credential provider chain.");
    return client;
}
/**
 * Type guard to check if an object is not empty.
 */
function isNotEmptyObject(obj) {
    return typeof obj === "object" && obj !== null && Object.keys(obj).length > 0;
}
/**
 * Fetches a single item from a DynamoDB table by its key.
 *
 * @template T The expected type of the unmarshalled item.
 * @param tableName The name of the DynamoDB table.
 * @param key The primary key of the item to fetch (use NativeAttributeValue format).
 * @param options Optional GetItemCommandInput options (e.g., ProjectionExpression).
 * @param context RequestContext containing AWS credentials.
 * @returns The requested item, unmarshalled to type T, or null if not found.
 */
export async function getDynamoDBItem(tableName, key, options = {}, context) {
    const commandInput = {
        TableName: tableName,
        Key: marshall(key),
        ...options,
    };
    try {
        const dbClient = getClient(context);
        const { Item } = await dbClient.send(new GetItemCommand(commandInput));
        return Item ? unmarshall(Item) : null;
    }
    catch (error) {
        handleDynamoDBError(error, `GetItem from ${tableName}`);
        throw error;
    }
}
/**
 * Queries a DynamoDB table or index.
 *
 * @template T The expected type of the unmarshalled items.
 * @param tableName The name of the DynamoDB table.
 * @param queryInput Query parameters (KeyConditionExpression, etc.).
 *                 Use ExpressionAttributeValues with NativeAttributeValue format for easier use.
 *                 Example: ExpressionAttributeValues: { ':val': 'someValue', ':num': 123 }
 * @param context RequestContext containing AWS credentials.
 * @returns An array of items matching the query, unmarshalled to type T[].
 */
export async function queryDynamoDB(tableName, queryInput, context) {
    const marshalledAttributes = queryInput.ExpressionAttributeValues &&
        isNotEmptyObject(queryInput.ExpressionAttributeValues)
        ? marshall(queryInput.ExpressionAttributeValues)
        : undefined;
    const commandInput = {
        TableName: tableName,
        ...queryInput,
        ExpressionAttributeValues: marshalledAttributes,
    };
    try {
        const dbClient = getClient(context);
        const { Items } = await dbClient.send(new QueryCommand(commandInput));
        return Items ? Items.map((item) => unmarshall(item)) : [];
    }
    catch (error) {
        handleDynamoDBError(error, `Query on ${tableName}`);
        throw error;
    }
}
// Centralized error handler
function handleDynamoDBError(error, context) {
    // Keep basic logging
    console.error(`DynamoDB error during operation (${context}):`, error);
    let suggestion = "";
    if (error instanceof Error) {
        // Adjust credential hint logic for default provider chain
        const errorMessage = error.message.toLowerCase();
        const errorName = error.name.toLowerCase();
        if (errorMessage.includes("credentials") ||
            errorMessage.includes("profile") ||
            errorMessage.includes("token") ||
            errorMessage.includes("region") || // Also check for region errors
            errorName.includes("credential") ||
            errorName.includes("token")) {
            suggestion =
                "Hint: Check AWS credentials configuration (environment variables, ~/.aws/credentials, ~/.aws/config, IAM role, SSO session) and ensure the AWS region is correctly set.";
        }
        console.error(`Error Name: ${error.name}, Message: ${error.message}`);
    }
    if (suggestion) {
        console.error("💡", suggestion);
    }
}
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