introduction to graphql

IntroductionOriginHistoryUsage

Alternatives & useful toolsEnd

GraphQL

Piotr Sroczkowski

Brainhub

January 23, 2017

Piotr Sroczkowski GraphQL

Summary I

1 Introduction

2 OriginDIPSemantic triple

3 History

4 UsageHow to setup a GraphQL server?SyntaxTypesBest practices

5 Alternatives & useful tools

What is GraphQL?

Graph query language

What is GraphQL?

Graph query language

DIPSemantic triple

Dependency inversion principle (DIP)

one of SOLID principles

depend on abstraction, not concretion

IMO even abstract class breaks this rule

so we should depend only on interfaces

DIPSemantic triple

DIP in services

DIP is not only in OOP

also in SOA

it’s like joining blocks together

DIPSemantic triple

DIP in services

also in SOA

DIPSemantic triple

DIP in services

also in SOA

DIPSemantic triple

DIP in services

also in SOA

DIPSemantic triple

DIP in microservices

it’s not a new paradigm, it’s just an example of SOA

service discovery

DIPSemantic triple

service discovery

DIPSemantic triple

service discovery

DIPSemantic triple

Semantic triple

an RDF (Resouce Description Framework) data model

ex. Alice likes Bob

DIPSemantic triple

Semantic triple

ex. Alice likes Bob

DIPSemantic triple

Semantic triple

ex. Alice likes Bob

DIPSemantic triple

Triplestore

a proposed database for storage of triples

DIPSemantic triple

Triplestore

a proposed database for storage of triples

DIPSemantic triple

Think in graphs

Graph algorithms

DIPSemantic triple

Think in graphs

Graph algorithms

DIPSemantic triple

Think in graphs

Graph algorithms

DIPSemantic triple

Think in graphs

Graph algorithms

GraphQL history

developed internally in Facebook in 2012

publicly released in 2015

GraphQL history

How to setup a GraphQL server?SyntaxTypesBest practices

express-graphqlhttps://github.com/graphql/express-graphql

or graphql-serverhttps://github.com/apollostack/graphql-server

The simplest way

1 git clone https:// github.com/apollostack/apollo -

↪→ starter -kit

2 cd apollo -starter -kit

3 git checkout server -only

4 npm install

5 npm start

Queries

2 hero {

3 name

2 "data": {

3 "hero": {

4 "name": "R2 -D2"

Queries

2 hero {

3 name

2 "data": {

3 "hero": {

4 "name": "R2 -D2"

Queries

2 hero {

3 name

2 "data": {

3 "hero": {

4 "name": "R2 -D2"

Queries

2 human(id: "1000") {

3 name

4 height

2 "data": {

3 "human": {

4 "name": "Luke Skywalker",

5 "height": 1.72

Queries

2 human(id: "1000") {

3 name

4 height

2 "data": {

3 "human": {

5 "height": 1.72

Queries

2 human(id: "1000") {

3 name

4 height

2 "data": {

3 "human": {

5 "height": 1.72

Aliases

2 empireHero: hero(episode: EMPIRE) {

3 name

5 jediHero: hero(episode: JEDI) {

6 name

2 "data": {

3 "empireHero": {

4 "name": "Luke Skywalker"

6 "jediHero": {

7 "name": "R2 -D2"

Aliases

3 name

6 name

2 "data": {

3 "empireHero": {

6 "jediHero": {

7 "name": "R2 -D2"

Aliases

3 name

6 name

2 "data": {

3 "empireHero": {

6 "jediHero": {

7 "name": "R2 -D2"

Fragments - input

2 leftComparison: hero(episode: EMPIRE) {

3 ... comparisonFields

5 rightComparison: hero(episode: JEDI) {

6 ... comparisonFields

10 fragment comparisonFields on Character {

11 name

12 appearsIn

13 friends {

14 name

Fragments - output I

2 "data": {

3 "leftComparison": {

5 "appearsIn": [

6 "NEWHOPE",

7 "EMPIRE",

8 "JEDI"

10 "friends": [

12 "name": "Han Solo"

15 "name": "Leia Organa"

Fragments - output II

18 "name": "C-3PO"

21 "name": "R2 -D2"

25 "rightComparison": {

26 "name": "R2 -D2",

27 "appearsIn": [

28 "NEWHOPE",

29 "EMPIRE",

30 "JEDI"

Fragments - output III

32 "friends": [

Variables - input I

1 query HeroNameAndFriends($episode: Episode) {

2 hero(episode: $episode) {

3 name

4 friends {

5 name

Variables - output I

2 "data": {

3 "hero": {

4 "name": "R2 -D2",

5 "friends": [

Variables - output II

Directives I

1 query Hero($episode: Episode , $withFriends: Boolean !)

↪→ {

2 hero(episode: $episode) {

3 name

4 friends @include(if: $withFriends) {

5 name

Mutations I

1 mutation CreateReviewForEpisode($ep: Episode!, $review

↪→ : ReviewInput !) {

2 createReview(episode: $ep , review: $review) {

3 stars

4 commentary

Inline fragments I

1 query HeroForEpisode($ep: Episode !) {

2 hero(episode: $ep) {

3 name

4 ... on Droid {

5 primaryFunction

7 ... on Human {

8 height

Meta fields I

2 search(text: "an") {

3 __typename

4 ... on Human {

5 name

7 ... on Droid {

8 name

10 ... on Starship {

11 name

Scalar types

Enumeration types

Interfaces

Union types

Input types

Scalar types

Enumeration types

Interfaces

Union types

Input types

Scalar types

Enumeration types

Interfaces

Union types

Input types

Scalar types

Enumeration types

Interfaces

Union types

Input types

Scalar types

Enumeration types

Interfaces

Union types

Input types

Scalar types

Enumeration types

Interfaces

Union types

Input types

Scalar types

String

Boolean

You can also define your custom scalar types ex. scalar Date

Scalar types

String

Boolean

Scalar types

String

Boolean

Scalar types

String

Boolean

Scalar types

String

Boolean

Scalar types

String

Boolean

Scalar types

String

Boolean

Enumeration types

1 enum Episode {

2 NEWHOPE

3 EMPIRE

4 JEDI

Type modifiers

1 type Character {

2 name: String!

3 appearsIn: [Episode ]!

Interface

1 interface Character {

2 id: ID!

3 name: String!

4 friends: [Character]

Interface implementation

1 type Human implements Character {

2 id: ID!

3 name: String!

4 friends: [Character]

6 starships: [Starship]

7 totalCredits: Int

Union types

1 union SearchResult = Human | Droid | Starship

Input types

1 input ReviewInput {

2 stars: Int!

3 commentary: String

1 mutation CreateReviewForEpisode($ep: Episode!,

↪→ $review: ReviewInput !) {

2 createReview(episode: $ep , review: $review)

↪→ {

3 stars

4 commentary

Input types

2 stars: Int!

↪→ {

3 stars

4 commentary

Input types

2 stars: Int!

↪→ {

3 stars

4 commentary

Best practices

JSON (with GZIP)

Versioning

Nullability

Pagination

Server-side Batching & Caching

Best practices

JSON (with GZIP)

Versioning

Nullability

Pagination

Best practices

JSON (with GZIP)

Versioning

Nullability

Pagination

Best practices

JSON (with GZIP)

Versioning

Nullability

Pagination

Best practices

JSON (with GZIP)

Versioning

Nullability

Pagination

Best practices

JSON (with GZIP)

Versioning

Nullability

Pagination

Best practices

JSON (with GZIP)

Versioning

Nullability

Pagination

Pagination example

2 hero {

3 name

4 friends(first :2) {

5 name

Batching - library

https://github.com/nodkz/react-relay-network-layer

Batching - library

https://github.com/nodkz/react-relay-network-layer

Useful tools

Relay https://github.com/facebook/relay

GraphiQL https://github.com/graphql/graphiql

Adrenaline https://github.com/gyzerok/adrenaline

Apollo clienthttps://github.com/apollostack/apollo-client

Apollo iOShttps://github.com/apollostack/apollo-ios

Useful tools

Alternatives

Falcor (not yet available)

SPARQL

Graph databases like Neo4j, ArangoDB

Alternatives

SPARQL

Alternatives

SPARQL

Alternatives

SPARQL

What problems does it solve?

client - server and microservices communication

more precise than REST

versioning

Sources

The examples have been got from GraphQL official sitehttp://graphql.org/learn/

Sources

The examples have been got from GraphQL official sitehttp://graphql.org/learn/

The end

Thank you

The end

Thank you

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