An intro to GraphQL
Suraj Paul
https://www.drupal.org/u/suraj2012

● Data Query Language developed by Facebook in 2012.
● Released publicly in 2015.
● 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.
● GraphQL isn't tied to any specific database or storage engine
and is instead backed by your existing code and data.
● Drupal 8 provides module to create and expose graphQL
schema. https://www.drupal.org/project/graphql
What is GraphQL ?

Core Ideas of GraphQL
● Client Requests and Server payloads have same structure.
● The server contains the schema.
● The client dictates what it wants from the server to
provide.

Limitations of RESTful APIs
● Multiple Endpoints -- Endpoints specific to individual views
● Response Bloats -- Response contains more data, mostly
unused.
● Many Round Trips -- Complex and relational data
containing URLs.
● No backwards Compatibility -- REST APIs are versioned
● Not Introspective -- Lack Native Schema, making client
side validation difficult

● Single Endpoint -- Single Endpoint can resolve GraphQL
queries and send a single, unified
response
● Tailored Response -- Response is catered with the client
demand
● Fewer Round Trips -- Returns a single response flexible to
accommodate many relationships
● Backward Compatibility -- common response for each
version
● Introspective -- Native and Highly Extensible Schema
How GraphQL Resolves this

Operations
GraphQL provide 2 types of operations
● Query
● Mutations
Query:
query {
nodeById(id: 1) {
title
}
}

Fields can describe relationships with other data. Fields return
values and can carry arguments.
Arguments
{
nodeById(id: "1") {
title
}
}
Arguments

Fragments
GraphQL includes reusable units called fragments. Fragments let you
construct sets of fields, and then include them in queries where you
need to.
fragment nodeFields on NodeArticle {
nid
type {
targetId
}
created
}
{ nodeQuery: nodeById(id: "2") {
...nodeFields
}
}

Variables
Sometimes we need to pass dynamic values to query. We can pass
dynamic values using variables in GraphQL.
query getArticle($nid: String!) {
nodeById(id: $nid) {
title
}
}
{
"nid": "2"
}

Mutation
● Most discussions of GraphQL focus on data fetching, but any
complete data platform needs a way to modify server-side data as
well.
● A module GraphQL Mutation is needed to perform POST
operations. https://www.drupal.org/project/graphql_mutation
● The module Adds GraphQL mutations for all content entities.

mutation ($input: NodeArticleCreateInput!) {
createNodeArticle(input: $input) {
violations {
path
message
}
errors
entity {
entityId
entityBundle
entityLabel
}
}
}
Mutation

● GraphQL in action in Drupal 8
Demo

Future in Drupal
● Decoupled Drupal using React & graphQL . An example is given on
https://github.com/fubhy/drupal-decoupled-app
● A number of modules supported by amazee.io.
https://www.amazeelabs.com/en/blog/drupal-graphql-batt
Eries-included
● Drupal and GraphQL with React and Apollo
https://www.amazeelabs.com/en/blog/drupal-graphql-react-apollo

Thank you