GraphQL is a powerful data querying and manipulation language, presenting itself as an alternative to REST in API development. This session is aimed at introducing the motivation behind GraphQL, and describe how it acts as an alternative to using REST when it comes to building data-driven applications. The importance of GraphQL APIs on serverless architectures will also be introduced, and the session will also demonstrate how GrapQL based APIs can be built with the help of AWS AppSync. This will segue the talk into the benefits of AppSync, specifically talking about the ability to access the AWS software infrastructure services while building your applications. AWS Lambda functions will be highlighted, and the session shall conclude with a demonstration on integrating Lambda functions into the GraphQL schema, a discussion of the problems of using Lambda functions with GraphQL, and the solution to the issues that surface.

1. Reshaping Data Driven Application
Development With GraphQl and AppSync

2. Syed Sarjeel Yusuf
@SarjeelY

3. Agenda:
What is GraphQL
Concept of GraphQL
Building on AppSync
Demo
Comparison with REST APIs

4. History of GraphQL
Querying Language
Specification
Developed by:
2009 - Race for mobile web begins
2012 - News feed with RESTful APIs
2015 - GraphQL goes open-source
2016 - Hopes of GraphQL being adopted

5. Exact Data
Get exactly what you
wanted
{
“me”: {
“name”:
“Yusuf”
}
}
query{
me{
name
}
}

6. Theory
Application Data
Graph

7. GraphQL
Build and expose APIs
No need for multiple endpoints
Get exact data
Real Time
Batching
Pagination
Relations
Aggregations
Search
Offline

8. Defining GraphQL
GraphQL has three top-level
operations:
● Query - read-only fetch
● Mutation - write,
followed by a fetch
● Subscription - long-lived
connection for receiving
data
{
"version": "2017-02-28",
"operation": "BatchInvoke",
"payload": {
"field": "relatedAnimals",
"source":
$utils.toJson($context.source)
}
}

9. Resolvers
Maps schema definitions with
functionality
Acts as logic for collecting data
Built in templates in AppSync
{
"version" : "2017-02-28",
"operation" : "addAnimal",
"key" : {
"id" : { "S" : "${ctx.args.id}" }
},
"attributeValues" :
$util.dynamodb.toMapValuesJson($ctx.args)
}

10. Querying Data
Can import methods from files
Lightweight - avoids
overfetching
Lets client decide what is
needed, UI-driven data fetching
query{
getAnimal(id: 2) {
id
name
food
}
}
mutation{
addAnimal(
id: 2
name: “Lion”
food: [“Impala”, “Wilderbeast”]) {
Name
}
}
query{
getAnimal(id: 2) {
food
}
}

11. Why Serverless
Single end point
Needs to be reliable and scalable
Pay-as-you-go

12. Using AppSync
Manage GraphQL service
Serverless back-end for
mobile, web, and enterprise
applications
Supports both online and
offline data interactions,
across multiple data sources

13. AppSync Set-up
Manage Single End-Point
Auth Functionality
API Key Generation

14. Resources
Easy to connect resources
Security in connecting to
data sources
DynamoDB
ElasticSearch
Lambda
None
HTTP
Relational Database

15. Resolver Templates
Easy to use
Templates depending on
dataresource
GetItem
PutItem
UpdateItem
DeleteItem
Query
Scan
Type System (Request Mapping)
Type System (Response Mapping)
Filters
Condition Expressions

16. Query Building
Query Functionality
Easy to build queries

17. Demo
Getting our hands
dirty

18. REST vs GraphQL
Will GraphQL kill REST
???
Depends on your usage

19. Thank you!
Questions