Introduction

This is a Starter application for using the Sample app in the AWS AppSync console when building your GraphQL API. The Sample app creates a GraphQL schema and provisions Amazon DynamoDB resources, then connects them appropriately with Resolvers. The application demonstrates GraphQL Mutations, Queries and Subscriptions using AWS AppSync. You can use this for learning purposes or adapt either the application or the GraphQL Schema to meet your needs.

Features

• GraphQL Mutations

  • Create new events
  • Create comments on existing events

• GraphQL Queries

  • Get all events (w/ pagination support)
  • Get an event by Id

• GraphQL Subscriptions

  • Real time updates for comments on an event

• Authorization

  • The app uses API Key as the authorization mechanism

Requirements

• Xcode 9 or later
• iOS 9 or later
• CocoaPods

AWS Setup

1. Navigate to the AWS AppSync console using the URL: http://console.aws.amazon.com/appsync/home

2. Click on Create API and select the Sample Schema option. Enter a API name of your choice. Click Create.

iOS Setup

Clone this repository:

git clone https://github.com/aws-samples/aws-mobile-appsync-events-starter-ios.git

From the homepage of your GraphQL API (you can click the name you entered in the left hand navigation) wait until the progress bar at the top has completed deploying your resources.

On this same page, select iOS at the bottom to download your AppSync.json configuration file. In the sample app which you just downloaded, copy the API URL and API Key from this JSON file and paste them into the Constants.swift file.

To setup the dependencies in the app, navigate to the project you just cloned from a terminal and run:

pod install

Now open EventsApp.xcworkspace.

Application Walkthrough

EventsAPI.swift

• The EventsAPI.swift file contains code generated through aws-appsync-codegen based on the GraphQL schema. It requires you to define a .graphql file and the schema.json for your API. For this example, they are in events.graphql and schema-events.json. If you update your schema in the future, you will find updated versions of these in the AWS AppSync console under the homepage for your GraphQL API when you click the iOS tab.

• To add new mutations, queries or subscriptions into your app, you could extend the events.graphql file to add additional operations.

• To generate a new API definition from the GraphQL schema, run:

npm install aws-appsync-codegen

aws-appsync-codegen generate events.graphql --schema schema-events.json --output EventsAPI.swift

This will generate an updated EventssAPI.swift file with additional operations.

EventListViewController (Query)

• The EventListViewController file lists all the events accessible to the user. It returns data from the offline cache first if available and later fetches it from remote to update the local cache.

EventDetailsViewController (Mutation, Query, Subscription)

• The EventDetailsViewController file lists information about an event and allows new comments to be added. It also subscribes to live updates for new comments which are made on that post.

AddEventViewController (Mutation)

• The AddEventViewController creates a new event using the details entered on screen.