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Ed Lima
Solutions Architect, Amazon Web Services
Taking Your Progressive Web App
To The Next Level With
GraphQL And AWS Appsync

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Digital Media
50%
34%
9%
7%
1 2 3 4
Time spent
comScore Media Metrix Multi-Platform & Mobile Metrix, U.S., Total Audience, June 2017

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comScore Media Metrix Multi-Platform & Mobile Metrix, U.S., Total Audience, June 2017
0
5
11
16
21
1
Series1 Series2
Average Monthly
Unique Visitors
2.2x
Mobile
App

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Progress To Progressive

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Progressive Web Apps (PWA)
Responsive web
application
Defined by
manifest.json
Discoverable and
installable
A Progressive Web App uses
modern web capabilities
to deliver
an app-like user experience

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Why Progressive Web Apps
Secure ShareableNetwork Agnostic Always up-to-date

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Core Components
Application shell Service worker Storage and cache

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Toolchain And Production Scale
• Web framework (Ember.js, Angular.js, Ionic, React, etc.)
• CLI/build system (Workbox, Ionic, Grunt/Gulp, AWS CLI)
• Libraries/utilities (Local Forage, Handlebars)
• Deployment (CloudFront, S3, AWS Mobile CLI, Mobile Hub)

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What About The Backend?

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Traditional Data Fetching
Data
 Trivial to set up
 Standard HTTP Calls
❌ Relationships
❌ Lists with reduced information
❌ Query support
❌ Ordering and pagination
❌ Notifications
/posts
/postInfo
/postJustTitle
/postsByAuthor
/postNameStartsX
/postByTag
/commentsOnPost
REST Endpoints

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Is There A Better Way

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GraphQL

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What Is GraphQL?
Describe what’s possible
with a type system
Uniform API across data stores
and APIs
Network optimised
requests and responses
Powerful developer tools Integrated
documentation and
introspection
Query language for your API
and a runtime for fulfilling
queries with existing data

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What Is GraphQL?
/posts /comments /authors
REST API
/posts /comments /authors
GraphQL API

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How To Use GraphQL
type Query {
listEvents: [Event]
}
type Event {
id: ID!
name: String!
when: String!
where: String!
}
query {
listEvents {
id
name
}
}
{
"id": "1",
"name": "React Meet Up"
},
{
"id": "2",
"name": "GraphQL Party"
},
{
“id”: “3”,
“name”: “Angular Sesh”
}
...
Define your data
(Schema)
Invoke Operation Get EXACTLY what
you asked for

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How To Use GraphQL
type Query {
listEvents: [Event]
}
type Event {
id: ID!
name: String!
when: String!
where: String!
}
query {
listEvents {
id
name
when
}
}
{
"id": "1”,
"name": "React Meet Up”,
“when”: “Tomorrow”
},
{
"id": "2",
"name": "GraphQL Party",
“when”: “Saturday”
},
{
“id”: “3”,
“name”: “Angular Sesh”,
“when”: “Next Friday”
}
...
Define your data
(Schema)
Invoke Operation Get EXACTLY what
you asked for

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GraphQL sounds legit!
I want to run my own GraphQL server!!

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Introducing AWS AppSync

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AWS AppSync
Managed Serverless
GraphQL service
Connect to data
sources in your account
Add data sync, real-time and
offline capabilities for any data
source or API
GraphQL façade for any
AWS service
Conflict detection and
resolution in the cloud
Enterprise security features
(IAM, Cognito, API keys)

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How Does AppSync Work?
Create, Import or Upload
GraphQL Schema
Amazon
Elasticsearch
Amazon
DynamoDB
AWS Lambda
Connect Data
Sources
AppSync Updates Data
in Real Time and Manages
Data when Offline
__________
______________
___________
_________
___________
____________
__________

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Mutations
Write Data
mutation {
createEvent(name:”MeetUp”){
id
}
}
GraphQL Operations
Queries
Read Data
query {
getEvent(id: 1){
id
name
}
}
Subscriptions
Receive Data in
Real-Time
subscription {
onCreateComment {
id
}
}
Queries
Read Data
Mutations
Write Data
Subscriptions
Receive Data in Real-Time

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Building Data-Driven Apps With AWS Appsync
Robust, scalable storage
capable of handling
millions of events a day
Geospatial
search
Real-time
updates for both
mobile and web
Mobile and Web
clients

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Clients receive the data
they ask for. Nothing
more, nothing less
Get many resources from
many data sources with a
single request
Self-documenting APIs with
Introspection
React Native, Android,
iOS, and Web (JS) using
the Apollo GraphQL client
Data persistence across
application restarts
Write-through mutations with
optimistic UI
AWS AppSync Benefits

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Real-Time Updates
• GraphQL subscriptions
• Event stream of mutation results
• Data synchronisation with MQTT + WebSockets
• Client managed WebSocket connection
• Automatic catch-up snapshots

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Amazon Elasticsearch
Amazon DynamoDB
Browser
Mobile
device WebSocket
servers
Web servers
PubSub
servers
Subscription
/search
/taps
/taps/:id
/m_search
AWS Lambda
Third-party service
…
Real-Time App Before AppSync

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/graphql
AWS AppSync
Subscription Amazon Elasticsearch
Amazon DynamoDB
AWS Lambda
Third-party service
Real-Time App After AppSync

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Data Conflicts
Jane
Version : 2 Updated Document
Jane
Version : 2 Updated Document
Version : 3 Updated Document
Version : 1 New Document
Time
John
John
Jane goes offline
Jane comes back online
Version : 4 Updated Document
John
Jane

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Handle Data Conflicts In The Cloud
• Conflict detection with optimistic version check
• Conflict resolution strategies:
A. Client wins
B. Server wins
C. Silent reject
D. Custom logic in AWS Lambda
• Client callback for conflict resolution is available
"condition" : {
"expression" : "someExpression"
"conditionalCheckFailedHandler" : {
"strategy" : "Custom",
"lambdaArn" : "arn:..."
}
}

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Offline Capabilities - AppSync Client Storage
• Offline is a write-through "Store"
• Persistent storage mediums back the Apollo
normalised cache
• Local Storage for web
• AsyncStorage for React Native
• SQLite on native platforms
• Database can be preloaded
• Offline client can be configured
• WiFi only
• WiFi and cellular

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Amazon API Gateway AWS AppSync

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Amazon API Gateway AWS AppSync
vs

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Amazon API Gateway AWS AppSync
vs

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Amazon API Gateway AWS AppSync
&

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Amazon API Gateway AWS AppSync
&

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Enough Talking…
https://github.com/aws-samples/aws-mobile-appsync-chat-starter-angular

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Amazon
Cognito
User Pools
JWT Token
GraphQL
Schema
ChatQL
Conversations
Table
Messages
Table
User Conversations
Table
Users Table
Amazon
DynamoDB
Queries and Mutations
Subscriptions
AppSync
Resolvers
User
AWS AppSync
AppSync Data Sources

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User
1..1
1..n
1..1
1..n
1..n
User
Conversation
Conversation Messages
GraphQL Relations between NoSQL DynamoDB Tables

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Demo Time!

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Takeaways
Don’t boil the ocean. Start small
and iterate on Offline (cache-and-
network), Real-time and Conflict
Resolution
Use UI cues with
Optimistic UI when
Offline
Take advantage of built-in
GraphQL powerful features
such as Connections
(Pagination) and Relations
(NoSQL)
It’s all about the
User Experience:
PWAs + AppSync = 

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It’s all about the User Experience !
https://secure.i.telegraph.co.uk/multimedia/archive/02884/babies_2884567b.jpg

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Thank You