The document discusses GraphQL as an alternative to REST for building APIs. It provides reasons for using GraphQL like simplified workflows with a single endpoint, avoiding over- and under-fetching of data, and improved developer experience. The document then covers GraphQL concepts like schemas, queries, mutations, subscriptions and best practices. It also provides a demo of building a GraphQL API in .NET and discusses strategies for migrating from REST to GraphQL.

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IS REST Dead? Learn through GraphQL.Net
Karthikeyan VK
https://blogs.karthikeyanvk.in
@karthik3030

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Why GRAPHQL?
Simplified Workflow(Single
endpoint)
Remove over and under fetching
Avoid multiple round trips

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Why GRAPHQL?
Type Safety
Increased velocity of
development
Improved developer experience

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Simplified Workflow

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Remove Over and Under fetching

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Avoid Multiple Round trips

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Type Safety

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Increased velocity of
development

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Improved developer experience

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Transition of Data Transfer
REST REST-RPC GRAPHQL

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DEMO

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What is GraphQL?
GraphQL is a query language for your API, and a
server-side runtime for executing queries by using a
type system you define for your data.

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What is Graph in GraphQL?

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What is GraphiQL?
GraphiQL is an interactive in-browser GraphQL IDE.

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DEMO

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Schema Types

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Queries
public class StarWarsQuery : ObjectGraphType
{
public StarWarsQuery()
{
Field<DroidType>( "hero", resolve: context => new Droid { Id = "1", Name = "R2-D2" } );
}
}

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Mutation
mutation newNHL($player: PlayerInput!)
{
createPlayer(player: $player)
{
name
id
}
}

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Subscriptions
Subscriptions creates a two way communication between the client and server like
SignalR

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Malicious Queries

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Validation and Authorization

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Validation and Authorization

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DEMO

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Best Practices
Naming Matters
Think in Graph and not in endpoints
Improved developer experience
Describe the data, not the view
Remember, GraphQL is thin Interface

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Best Practices
Naming Matters
Think in Graph and not in endpoints
Improved developer experience
Describe the data, not the view
Remember, GraphQL is thin Interface

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Migration Strategies
Solve a real problem
Think like a client
Have a first client
Incremental Adoption
Finally YAGNI

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References
@karthik3030
• https://graphql-dotnet.github.io/docs/getting-started/introduction
• https://fullstackmark.com/post/17/building-a-graphql-api-with-aspnet-core-2-and-entity-
framework-core

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@karthik3030
Thank you
/Q&A