graphql.js

const { graphql, buildSchema } = require('graphql');
const { makeExecutableSchema } = require('graphql-tools');
const AWS = require('aws-sdk');

// Set up AWS DynamoDB
const dynamodb = new AWS.DynamoDB.DocumentClient();
const tableName = 'Items'; // Your DynamoDB table name

// Define your GraphQL schema
const typeDefs = `
  type Item {
    itemId: String!
    name: String!
    description: String
  }

  type Query {
    getItem(itemId: String!): Item
  }

  type Mutation {
    createItem(itemId: String!, name: String!, description: String): Item
    updateItem(itemId: String!, name: String!, description: String): Item
    deleteItem(itemId: String!): Item
  }
`;

// Define resolvers for your schema
const resolvers = {
  Query: {
    getItem: async (_, { itemId }) => {
      const params = {
        TableName: tableName,
        Key: { itemId },
      };
      const response = await dynamodb.get(params).promise();
      return response.Item;
    },
  },
  Mutation: {
    createItem: async (_, args) => {
      const params = {
        TableName: tableName,
        Item: args,
      };
      await dynamodb.put(params).promise();
      return args;
    },
    updateItem: async (_, args) => {
      const params = {
        TableName: tableName,
        Key: { itemId: args.itemId },
        UpdateExpression: 'SET name = :name, description = :description',
        ExpressionAttributeValues: {
          ':name': args.name,
          ':description': args.description || null,
        },
        ReturnValues: 'ALL_NEW',
      };
      const response = await dynamodb.update(params).promise();
      return response.Attributes;
    },
    deleteItem: async (_, { itemId }) => {
      const params = {
        TableName: tableName,
        Key: { itemId },
        ReturnValues: 'ALL_OLD',
      };
      const response = await dynamodb.delete(params).promise();
      return response.Attributes;
    },
  },
};

const schema = makeExecutableSchema({
  typeDefs,
  resolvers,
});

// Handler function for AWS Lambda
exports.handler = async (event) => {
  const body = JSON.parse(event.body);
  const response = await graphql(schema, body.query, null, null, body.variables);
  return {
    statusCode: 200,
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(response),
  };
};