Example AppSync GraphQL API

chat-api.ts

/* Imports from CDK */
import * as appsync from '@aws-cdk/aws-appsync';
import * as db from '@aws-cdk/aws-dynamodb';

/* Creating the API */
const api = new appsync.GraphQLApi(this, 'Api', {
  name: 'my-chat-app', // API name
  schemaDefinition: appsync.SchemaDefinition.FILE, // Type of schema
  schemaDefinitionFile: './schema.graphql', // location of schema
  authorizationConfig: { // authorization config
    defaultAuthorization: {
      authorizationType: appsync.AuthorizationType.API_KEY
    },
  }
});

/* Create the DynamoDB table */
const messageTable = new db.Table(this, 'MessageTable', {
  partitionKey: {
    name: 'id',
    type: db.AttributeType.STRING,
  },
});

/* Connect the table to the API */
const messageDS = api.addDynamoDbDataSource('messageDataSource', 'Table for Messages"', messageTable);

// Resolver for the Query "getMessages" that scans the DyanmoDb table and returns the messages.
messageDS.createResolver({
  typeName: 'Query',
  fieldName: 'getMessages',
  requestMappingTemplate: MappingTemplate.dynamoDbScanTable(),
  responseMappingTemplate: MappingTemplate.dynamoDbResultList(),
});

// Resolver for the Mutation "createMessage" that puts the item into the DynamoDb table.
messageDS.createResolver({
  typeName: 'Mutation',
  fieldName: 'createMessage',
  requestMappingTemplate: MappingTemplate.dynamoDbPutItem(PrimaryKey.partition('id').auto(), Values.projecting('message')),
  responseMappingTemplate: MappingTemplate.dynamoDbResultItem(),
});