handler.js

const { ApolloServer, gql } = require("apollo-server-lambda");
const AWS = require("aws-sdk");

const dynamoDb = new AWS.DynamoDB.DocumentClient();

const typeDefs = gql`
  type Recipe {
    recipeId: Int
    recipeName: String
    description: String
    carbs: Int
    preparationTimeMin: Int
    preparationTimeMax: Int
    difficulty: Int
    mainImageEntry: String
    foodType: String
  }

  type Comment {
    userName: String
    comment: String
  }

  type Step {
    step: String
  }

  type Rating {
    userName: String
    rating: Int
  }

  type RecipeDetails {
    recipeId: Int
    stepsCount: Int
    comments: [Comment]
    steps: [Step]
    ratings: [Rating]
  }

  type Query {
    hello: String
    getRecipes: [Recipe]
    getRecipeDetails: RecipeDetails
  }
`;

const getRecipes = async () => {
  const params = {
    TableName: process.env.KETO_RECIPES
  };

  return new Promise((resolve, reject) => {
    dynamoDb.scan(params, (error, result) => {
      if (error) {
        reject(error);
      } else if (!result.Items) {
        resolve(null);
      } else {
        resolve(result.Items);
      }
    })
  });
};

const getRecipeDetails = async (recipeId) => {
  const params = {
    TableName: process.env.KETO_RECIPE_DETAILS,
    Key: { recipeId: recipeId }
  };

  return new Promise((resolve, reject) => {
    dynamoDb.get(params, (error, result) => {
      if (error) {
        reject(error);
      } else if (!result.Item) {
        resolve(null);
      } else {
        resolve(result.Item);
      }
    })
  });
};

const resolvers = {
  Query: {
    hello: () => 'Hello world!',
    getRecipes,
    getRecipeDetails
  },
};

const server = new ApolloServer({
  typeDefs,
  resolvers,
  context: ({ event, context }) => ({
    headers: event.headers,
    functionName: context.functionName,
    event,
    context,
  }),
});

exports.graphql = server.createHandler();