serverless-sam/integration_tests/tmp/aws-node-graphql-api-with-dynamodb/handler.js

Serverless framework plugin to export AWS SAM templates for a service

const {
  graphql,
  GraphQLSchema,
  GraphQLObjectType,
  GraphQLString,
  GraphQLNonNull,
} = require('graphql');

const AWS = require('aws-sdk');

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

const promisify = foo => new Promise((resolve, reject) => {
  foo((error, result) => {
    if (error) {
      reject(error);
    } else {
      resolve(result);
    }
  });
});

const getGreeting = firstName => promisify(callback =>
  dynamoDb.get({
    TableName: process.env.DYNAMODB_TABLE,
    Key: { firstName },
  }, callback))
  .then((result) => {
    if (!result.Item) {
      return firstName;
    }
    return result.Item.nickname;
  })
  .then(name => `Hello, ${name}.`);

const changeNickname = (firstName, nickname) => promisify(callback =>
  dynamoDb.update({
    TableName: process.env.DYNAMODB_TABLE,
    Key: { firstName },
    UpdateExpression: 'SET nickname = :nickname',
    ExpressionAttributeValues: {
      ':nickname': nickname,
    },
  }, callback))
  .then(() => nickname);

const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'RootQueryType', // an arbitrary name
    fields: {
      // the query has a field called 'greeting'
      greeting: {
        // we need to know the user's name to greet them
        args: { firstName: { name: 'firstName', type: new GraphQLNonNull(GraphQLString) } },
        // the greeting message is a string
        type: GraphQLString,
        // resolve to a greeting message
        resolve: (parent, args) => getGreeting(args.firstName),
      },
    },
  }),
  mutation: new GraphQLObjectType({
    name: 'RootMutationType', // an arbitrary name
    fields: {
      changeNickname: {
        args: {
          firstName: { name: 'firstName', type: new GraphQLNonNull(GraphQLString) },
          nickname: { name: 'nickname', type: new GraphQLNonNull(GraphQLString) },
        },
        type: GraphQLString,
        resolve: (parent, args) => changeNickname(args.firstName, args.nickname),
      },
    },
  }),
});

// We want to make a GET request with ?query=<graphql query>
// The event properties are specific to AWS. Other providers will differ.
module.exports.query = (event, context, callback) =>
  graphql(schema, event.queryStringParameters.query)
  .then(
    result => callback(null, { statusCode: 200, body: JSON.stringify(result) }),
    err => callback(err),
  );