GraphQL

1. GraphQL basics

2. Demo

3. Tooling

4. Sums up

AGENDA

GraphQL is first

of all a spec

Basics

• GraphQL has only one official implementation - NodeJS SDK. The rest is 3rd party
• performance can be blazing fast or slow
• spec totals 8k lines (JSON:API 2k)

GraphQL requires

a schema

Basics

• one or multiple .graphql files
• types & fields
• queries, mutations, subscriptions

Basics

Queries, mutations

• call any query or mutation
• select any fields on response
• must specify which fields to select
• can accept parameters

Basics

Multiple operations

• select multiple queries concurrently
• execute multiple mutations in order
• split big mutations into smaller chunks,
  making them easy to reuse

Basics

Fragments

• share selected fields across requests
• specify needed fields on component level

Basics

Subscriptions

• select fields, same as on queries and mutations
• subscribe to "subscriptions" - similar to Pusher's channels
• use any implementation - WS, HTTP, Pusher

Basics

Schema split across

multiple files

DEMO

Let's see how it works

Tooling

Document

• describe all types with fields
  & their types
• enums, enum values
• "endpoints" - queries, mutations,
  websocket subscriptions
• scalars - special primitives, like datetime, email, IP address, currency
• custom descriptions
• field deprecations

Tooling

Explore in web

• test queries/mutations
• use auto-complete to find queries, mutations, types and fields
• validate your fields selection

Tooling

Track

• track breaking changes with Slack notifications
• store all versions of a schema
• highlight schema changes on pull requests
• generate changelog

Tooling

Fedarate

• generate GraphQL APIs
  based on other APIs
• combine multiple GraphQL APIs in one
• transform for specific use - rename, replace, extend, merge fields & types
• turn existing REST APIs into GraphQL

Tooling

Generate code

• convert whole schema into code - types, enums, queries
• generate inputs & responses for queries & mutations
• injectable services for Angular
• supports TypeScript, Java, Kotlin & C#

Tooling

GraphQL is growing

• 174 tools, libraries, SDKs listed on official GraphQL site
• 330 on "awesome GraphQL" list
• used by GitHub, Facebook, PayPal and Twitter

Sums up

GraphQL (PHP lib and code generator only): 250k lines

Our whole app (with tests): 700k lines

Building APIs properly is a lot of effort

Sums up

GraphQL does a lot:

• statically types the API, making it more error-prone
• makes the code much simpler to write, understand and support
• has subscription, rendering Pusher useless
• allows multiple queries/mutations in single request
• generates ready-to-use client code, saving time and mistakes of frontend & mobile

• boosts productivity by providing user-friendly tools
• provides documentation, not only for "REST" API, but for websockets too
• opens up possibilities of exposing API to the public
• allows automatically tracking (possibly breaking) changes in APIs for both clients & backend developers
• has a huge ecosystem of tools and libraries

Sums up

Questions?