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GraphQL IndyJS April 2016

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A brief overview of GraphQL presented at the April 2016 IndyJS meetup.

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GraphQL IndyJS April 2016

  1. 1. GRAPHQL INDYJS MEETUP APRIL 2016
  2. 2. MEMES…
  3. 3. REST REST IS AN ACRONYM FOR ?
  4. 4. REST REST HISTORY ▸ The term representational state transfer was introduced and defined in 2000 by Roy Fielding ▸ The defacto standard for communicating with a server ▸ Defines simple operations: GET, PUT, POST, DELETE ▸ A query operation (like GET) promises no side-effects (e.g. changes) in data being queried. Commands (like PUT/DELETE) answer no questions about the data, but compute changes applied to the data (e.g. UPDATE or INSERT to use database terms).
  5. 5. REST REST ISSUES ▸ Many endpoints - proliferation of ad hoc endpoints ▸ Many round trips between the client and server ▸ First fetch pilots, then fetch homeworld info for each pilot, then… ▸ Very expensive for mobile apps ▸ Response structure may change over time ▸ Data overfetching ▸ We don’t always need all the data for a REST call ▸ Usually no metadata ▸ Big blob of data…we can’t run inquires on it’s types or structure

  6. 6. REST FIXES FOR REST?? ▸ Define your own ad-hoc query language ▸ Use REST PATCH to minimize data transfer ? ▸ REST API introspection via Swagger (http://swagger.io/)
  7. 7. GRAPHQL JAVASCRIPT FATIGUE BECAUSE A NEW JAVASCRIPT FRAMEWORK IS RELEASED
  8. 8. GRAPHQL WHAT IS GRAPHQL? ▸ Queries describe the shape of data that the client needs. The response has the same structure as the request query. ▸ Server interprets GraphQL calls and queries the database (or any other source of data) ▸ GraphQL is language-, database- and protocol-agnostic 

  9. 9. GRAPHQL WAS INVENTED AT FACEBOOK IN 2012, BUT IT WAS FIRST SHOWN TO PUBLIC IN 2015 DURING REACT.JS CONF AS A PART OF FACEBOOK OPEN-SOURCE ECOSYSTEM.
  10. 10. GRAPHQL GRAPHQL MOTIVATION ▸ Single endpoint ▸ Hierarchical nature ▸ Strongly typed - enables validation, introspection and more ▸ Response mirrors the shape of the query ▸ Introspection - make inquiries from your client about the schema ▸ Application-Layer Protocol ▸ GraphQL is an application-layer protocol and does not require a particular transport. It is a string that is parsed and interpreted by a server.
  11. 11. GRAPHQL GRAPHS - DAG/AST * - 397 + 6 DIRECTED ACYCLIC GRAPH ABSTRACT SYNTAX TREES (6 + 7) * (9 - 3)
  12. 12. GRAPHQL GRAPHS PERSON [NAME, ID, …] STARSHIP-A [ID, MANUF,..] STARSHIP-B [ID, MANUF,..] STARSHIP-C [ID, MANUF,..] PILOT-A [ID, NAME,..] STARSHIPCONNECTION STARSHIPCONNECTION STARSHIP CONNECTION PILOT CONNECTION HOMEWORLD-A [ID, NAME,..] HOMEWORLD CONNECTION HOMEWORLDCONNECTION NODE NODE EDGE
  13. 13. GRAPHQL FOLLOW ALONG! ▸ Go here and follow along with me ▸ http://graphql-swapi.parseapp.com
  14. 14. GRAPHQL BASIC QUERY
  15. 15. GRAPHQL NESTED FIELDS
  16. 16. GRAPHQL CONNECTIONS
  17. 17. GRAPHQL MANY CONNECTIONS
  18. 18. GRAPHQL ARGUMENTS
  19. 19. GRAPHQL FRAGMENTS
  20. 20. GRAPHQL MORE FRAGMENTS
  21. 21. GRAPHQL INTROSPECTION
  22. 22. GRAPHQL SCARED YET? ▸ Syntax (covered) ▸ Type System ▸ Resolving ▸ Edges/Nodes & Pagination
  23. 23. GRAPHQL GRAPHQL TYPE SYSTEM ▸ Scalars - basic types ▸ Schema - a representation of the capabilities of the GraphQL server ▸ Definitions - defining types ▸ Predicates - meta info on types ▸ Un-modifiers - type “un” modifiers
  24. 24. GRAPHQL GRAPHQL SCALARS ▸ GraphQLInt - integer number ▸ GraphQLFloat - float number ▸ GraphQLString - string ▸ GraphQLBoolean - boolean ▸ GraphQLID - represents an ID (essentially a string)
  25. 25. GRAPHQL GRAPHQL SCHEMAS ▸ It all starts with a “root” query ▸ Fields on type can be plain data or “resolved” ▸ You can define your own types ▸ You can define/override the serialization on a type ▸ You can add enhanced validation to types ▸ From a schema, you can generate a more human readable schema and JSON based schema for clients to use
  26. 26. GRAPHQL GRAPHQL DEFINITIONS ▸ GraphQLScalarType - the class of scalars ▸ GraphQLObjectType - an object ▸ GraphQLInterfaceType - a interface ▸ GraphQLUnionType - a union ▸ GraphQLEnumType - enum ▸ GraphQLInputObjectType ▸ GraphQLList - what you use for lists arrays of objects ▸ GraphQLNonNull - an object for which null is an invalid value
  27. 27. GRAPHQL GRAPHQL DATA RESOLUTION ▸ Resolve to data - synchronous result. Return the data as teh result of a resolve. ▸ Resolve to promise - asynchronous result. Return a promise that will return the data in the future. My preference is to use ES6 and async functions (which actually return promises).
  28. 28. GRAPHQL GRAPHQL EDGES/NODES ▸ Not built into the language, but provided by types ▸ The type Facebook uses and I recommend you use too, are in : https://github.com/graphql/graphql-relay-js ▸ Using edges and nodes allow for pagination. If you don’t need pagination, then use a simple GraphQLList.
  29. 29. GRAPHQL RUNNING ON EXPRESS https://github.com/graphql/graphql-js
  30. 30. GRAPHQL EXAMPLE SCHEMA
  31. 31. GRAPHQL CUSTOM SCALAR Credits: Snippet from https://github.com/mattkrick/meatier
  32. 32. GRAPHQL BUILD IT! ▸ Build your server…I use Babel and ES6 ▸ You’ll also need to run (see sample code) a script to “update” your schema. This creates a client and a human readable version of your schema. ▸ If you are using Relay, you will also need to use the Babel- Relay plugin to consume, compile and validate your GraphQL queries in your components. ▸ You also need to tell the Babel-Relay plugin where to find the schema you built above (the JSON form).
  33. 33. GRAPHQL MAKE SENSE? ▸ Hopefully more sense than Chewy!
  34. 34. GRAPHQL GRAPHQL MISUNDERSTANDINGS ▸ All of the queries you see are defined by your schema. I.e. things like viewer, user, edge, node are defined by the schema and not an inherent part of the language. ▸ GraphQL is Javascript only. Nope! ▸ There are 3rd party ports for Python, Scala, Go, Ruby, etc. ▸ GraphQL requires special communications protocol. Nope! ▸ The default implementation uses a basic REST post call, but you can use web sockets, etc. and even mix and match.
  35. 35. GRAPHQL & RELAY RESOURCES ▸ Cartoon Guides To GraphQL: https://code- cartoons.com ▸ Awesome GraphQL - curated list on Github: https://github.com/ chentsulin/awesome- graphql
  36. 36. GRAPHQL & RELAY MORE RESOURCES ▸ GraphQL Home: http://graphql.org/ ▸ GraphQL Spec: https://facebook.github.io/graphql/ ▸ Many REST APIs you can experiment with using GraphQL: https://www.graphqlhub.com/
  37. 37. QUESTIONS???▸ Twitter: @BradPillow, GitHub: pillowsoft THANKS!

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