🔌 REST API 설계

// CRUD Lambda 핸들러 (Node.js 20.x)
import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
import { PutCommand, GetCommand, ScanCommand, UpdateCommand, DeleteCommand, DynamoDBDocumentClient } from '@aws-sdk/lib-dynamodb';
import crypto from 'crypto';
 
const client = DynamoDBDocumentClient.from(new DynamoDBClient({}));
const TABLE = process.env.TABLE_NAME || 'lab-items';
 
export const handler = async (event) => {
  const method = event.httpMethod;
  const id = event.pathParameters?.id;
 
  try {
    switch (method) {
      case 'GET':
        if (id) {
          const { Item } = await client.send(new GetCommand({ TableName: TABLE, Key: { id } }));
          if (!Item) return response(404, { error: '항목을 찾을 수 없습니다' });
          return response(200, Item);
        }
        const { Items } = await client.send(new ScanCommand({ TableName: TABLE }));
        return response(200, Items);
 
      case 'POST': {
        const body = JSON.parse(event.body);
        const item = { id: crypto.randomUUID(), ...body, createdAt: new Date().toISOString(), completed: false };
        await client.send(new PutCommand({ TableName: TABLE, Item: item }));
        return response(201, item);
      }
      case 'PUT': {
        const body = JSON.parse(event.body);
        await client.send(new UpdateCommand({
          TableName: TABLE, Key: { id },
          UpdateExpression: 'SET title = :t, completed = :c, updatedAt = :u',
          ExpressionAttributeValues: { ':t': body.title, ':c': body.completed, ':u': new Date().toISOString() },
        }));
        return response(200, { message: '수정 완료' });
      }
      case 'DELETE':
        await client.send(new DeleteCommand({ TableName: TABLE, Key: { id } }));
        return response(200, { message: '삭제 완료' });
 
      default:
        return response(405, { error: '지원하지 않는 메서드입니다' });
    }
  } catch (err) {
    return response(500, { error: err.message });
  }
};
 
const response = (statusCode, body) => ({
  statusCode,
  headers: { 'Content-Type': 'application/json', 'Access-Control-Allow-Origin': '*' },
  body: JSON.stringify(body),
});