GraphQL is a great way to expose your APIs and it has changed the way we think about consuming data over HTTP. With GraphQL we want to have one schema that provides all the data to us in a consistent way, enabling us to drill into the graph and fetch with one request what we actually want instead of having to issue multiple requests. In the real world, however, we more often build small services that serve certain use cases. Simpler services are easier to maintain and can be deployed more rapidly. Moreover, we often also want to use external services that are not built by us. Ultimately, we will end up with multiple APIs again. The solution for this dilemma is schema stitching. This talk will explore the schema stitching capabilities on ASP.Net Core with Hot Chocolate. We will show how you can set up a Hot Chocolate GraphQL gateway in under 5 minutes and move on to the various stitching scenarios. This talk introduces simple auto-stitching scenarios and goes on to demonstrate how you can rewrite your GraphQL APIs into something truly new.

1. GraphQL on ASP.NET Core
WITH

2. Who are we?

3. Who is this for?Who is this for?

4. demo.chillicream.com

6. query {
me {
name
age
}
}
{
"me": {
"name": "Foo",
"age": 99
}
}

7. GET
https://webservices.amazon.com/onca/xml?
Service=AWSECommerceService&
AWSAccessKeyId=mY-Sup3r-s3cr3!-k3y&
AssociateTag=12345&
Operation=ItemLookup&
ItemId=0316067938&
ResponseGroup=Reviews&
TruncateReviewsAt=256&
IncludeReviewsSummary=False&
Version=2013-08-01&
Timestamp=[YYYY-MM-DDThh:mm:ssZ]&
Signature=[Request Signature]

10. What is GraphQL?

11. GraphQL
No over- or under-fetching
One Request
Type System
No versioning
Simplicity
One Endpoint
Documentation
Real-time
Predictability

12. What GraphQL is not:
• Graph database query language
• Solution for binary streams
• Facebooks version of OData
• Bound to a specific data source
• Limited to HTTP
• Limited to the JavaScript world
• A good solution for a health
check endpoint.

13. REST GraphQL
Shared Definition No Yes
Conceptual Model Resources Graphs
Organization Federated Centralized
Related Ops Yes No
Introspection No Yes
Data Typing Weak Strong
Real-Time No Yes

14. GraphQL Operations:
• Query = Read
• Mutation = Write
• Subscription = Events

15. Demo

16. Resolvers and Pipelines

17. Demo

19. query {
me {
friends {
friends {
friends {
name
}
}
}
}
}

20. Demo

21. Scaling Your Graph

22. query {
me {
name
age
}
}

23. query {
me {
name
age
friends {
name
age
}
}
}

24. query {
me {
friends {
friends {
friends {
name
}
}
}
}
}

25. query {
me {
name
stories(first: 10) {
... Content
}
}
}

26. query {
me {
name
stories(first: 10000) {
... Content
}
}
}

28. type User {
stories(first: PaginationAmount): [Story!]!
}
SchemaBuilder.New()
.AddType(new PaginationAmountType(50))
...
.Create();
type User {
stories(first: Int): [Story!]!
}

29. type User {
stories(first: PaginationAmount): [Story!]!
@cost(complexity: 5)
}

30. type User {
stories(first: PaginationAmount): [Story!]!
@cost(complexity: 5 multipliers:[first])
}

31. 1
1 50
me
Stories(first: 10)name

32. 1
1 5000
me
Stories(first: 1000)name

33. Demo

34. Persisted Queries

35. GraphQL Client GraphQL Server
High Bandwidth Usage
{
"query" : <query>
}

36. GraphQL Client GraphQL Server
Unrestricted Query Execution
{
"query" : <query>
}

37. GraphQL Client GraphQL Server
Low Bandwidth Usage
{
“id” : “W5IYenw==”
}
Middleware

38. GraphQL Client GraphQL Server
Restricted Query Execution
{
“id” : “W5IYenw==”
}
Middleware

39. Demo

40. Testing Your Schema

41. Demo

42. How can we do microservices with
that?

43. What is
schema
stitching?

44. The capability to merge multiple
GraphQL schemas into one
schema.

45. Hot Chocolate Gateway
Hot Chocolate GraphQL
Mongo DBRaven DB
Abritray REST Endpoint
{REST}
SQL Server
query {
me {
messages {
# Hot Chocolate GraphQL
text
# Apollo Server
createdBy {
name
}
# Abritray REST Endpoint
views
likes
replies
}
}
}
One GraphQL Query
Apollo GraphQL

46. Demo

48. Where do you find us?
https://github.com/ChilliCream
https://chillicream.com
https://hotchocolate.io
https://twitter.com/Chilli_Cream