GRAPHQL AS AN ALTERNATIVE APPROACH TO - REST - CODEMONSTERS NOV 2018
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GraphQL as an alternative approach to REST 1 @luisw19
About me
Luis Weir
CTO at Capgemini UK Oracle
Ace Director & Groundbreaker Ambassador
luis.weir@capgemini.com
uk.linkedin.com/in/lweir
http://www.soa4u.co.uk
Want the slides? I’ll share via:
@luisw19
tinyurl.com/eapim18 apiplatform.cloud/
Goes to Print Q2 2019 Released Q2 2018
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GraphQL as an alternative appraoch to REST
GraphQL – context & key
01
concepts
02 Demos
03 GraphQL vs REST PoV
04 Conclusions
©32018 Capgemini. All rights reserved. @luisw19
Application Programming Interfaces (APIs) are doors to
information and functionality.
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01
But some doors can be unfit for purpose…
source: https://imgur.com/a/J3ttg
5 @luisw19
6
01
Why GraphQL?
Source: https://dev-blog.apollodata.com/graphql-vs-rest-
5d425123e34b by Sashko Stubailo
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7
01
GraphQL - Background
• Created by Facebook in 2012 to get around a common constraints in
the REST approach when fetching data
• Publicly released in 2015
• GraphQL Schema Definition Language (SDL) added to spec in Feb’18
https://GraphQL.org
Latest release: http://facebook.github.io/graphql
Latest draft: http://facebook.github.io/graphql/draft/
7 @luisw19
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01
GraphQL – What is it NOT?
necessarily a
in spite of its name, it
replacement for REST.
has nothing to do with
Both can work together
Graphs DBs
a query language
for a databases
A silver Bullet
8 Roy from the IT Crowed à @luisw19
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01
GraphQL – What is it then?
A consumer oriented query language, a strongly typed schema
language and a runtime to implement GraphQL services.
Define Schema Quickly write and Get exactly what
run queries you asked for
type Country { {
id: ID! { "data": {
name: String! getCountries(name:"great") "countries": [
code: String! { {
} name "name": "United
type query { } Kingdom"
countries: } }
[Country] ]
} }
}
GraphQL Service GraphQL Client GraphQL Client
9 @luisw19
10
01
Who is using it?
Lots of organisations are embracing GraphQL: http://graphql.org/users
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01
Increasing rapidly in Popularity
GraphQL REST API OData
Jan 2016 Dec 2018
https://trends.google.com/trends/explore?date=2016-01-01%202018-12-01&q=GraphQL,REST%20API,OData
11 @luisw1912
01
Let’s put it into perspective
GraphQL REST API OData WSDL
trend
Feb 2004 Sep 2018
https://trends.google.com/trends/explore?date=2004-01-10%202018-11-30&q=GraphQL,REST%20API,OData,WSDL
12 @luisw1913
01
GraphQL – Key Concepts
There are 5 key characteristics of GraphQL that are
important to understand:
1 2 3 4 5
Hierarchical View-centric Strongly-typed Introspective Version-Free
Queries as By design built to A GraphQL The type system GraphQL takes a
hierarchies of satisfy frontend server defines a itself is strong opinion
data definitions, application specific type queryable. Tools on avoiding
shaped just how requirements. system. Queries are built around versioning by
data is expected are executed this capability. providing the
to be retuned. within this tools for the
context. continuous
evolution.
13 @luisw1914
01
GraphQL – Anatomy
GraphQL (Data) Types
Schema (Object, Input, Scalar,
Definition Enum, Interface, Union)
Language
GraphQL
have
Server
Implementation
Queries
(operation type)
Define
GraphQL Types
Schema have
Execute Resolvers
Mutations
(operation type)
f(x), f(x), f(x)
have
Subscriptions
(operation type)
14 @luisw1915
01
GraphQL – Anatomy
GraphQL (Data) Types
Schema (Object, Input, Scalar,
Definition Enum, Interface, Union)
Language
GraphQL
have
Server
Implementation
Queries
1 Define
(operation type)
GraphQL Types
Schema have
Execute Resolvers
Effectively the blueprint of Mutations
f(x), f(x), f(x)
a GraphQL API, it defines (operation type)
the Types, Queries and
Mutations supported in a have
GraphQL service
Subscriptions
(operation type)
15 @luisw1916
01
GraphQL – Anatomy
GraphQL
2 (Data) Types
(Object, Input, Scalar, Object, Input, Scalar, Enumeration,
Schema
Definition Enum, Interface, Union) Interfaces and Unions are all types
Language to define data structures, which are
GraphQL
have used in Operation types. Server
Implementation
Queries
(operation type)
Define
GraphQL Types
Schema have
Execute Resolvers
Mutations
(operation type)
f(x), f(x), f(x)
have
Subscriptions
(operation type)
16 @luisw1917
01
GraphQL – Anatomy
GraphQL (Data) Types
Schema (Object, Input, Scalar,
Definition Enum, Interface, Union)
Language
GraphQL
have Entry point for operationsServer
that fetch
3 data (read / search). Note that a
Implementation
Queries single Query type can define
(operation type)
GraphQL
Define multiple query operations.
Types
Schema have
Execute Resolvers
Mutations
(operation type)
f(x), f(x), f(x)
have
Subscriptions
(operation type)
17 @luisw1918
01
GraphQL – Key Concepts
GraphQL (Data) Types
Schema (Object, Input, Scalar,
Definition Enum, Interface, Union)
Language
GraphQL
have
Server
Implementation
Queries
(operation type)
Define
GraphQL Types
Schema have
4 Execute Resolvers
Mutations
(operation type)
f(x), f(x), f(x)
Entry point for operations that
create/update data via a GraphQL
service. Note that a single Mutation have
type can define multiple mutation
operations. Subscriptions
(operation type)
18 @luisw1919
01
GraphQL – Anatomy
GraphQL (Data) Types
Schema (Object, Input, Scalar,
Definition Enum, Interface, Union)
Language
GraphQL
have
Server
Implementation
Queries
(operation type)
Define
GraphQL Types
Schema have
Execute Resolvers
Mutations
(operation type)
f(x), f(x), f(x)
have
5 *new* Pub/sub system for near-
Subscriptions realtime updates. Unlike queries or
(operation type) mutations, it can deliver more than
one result via push.
19 @luisw1920
01
GraphQL – Anatomy
GraphQL (Data) Types
Schema (Object, Input, Scalar,
Definition Enum, Interface, Union)
Language
GraphQL
have
Server
Functions that define how each
Implementation
Queries field, within a GraphQL Query or
(operation type)
Define Operation is to be acted upon.
GraphQL Types
Schema have
Execute Resolvers
Mutations
(operation type)
f(x), f(x), f(x)
6
have
Subscriptions
(operation type)
20 @luisw1921
01
GraphQL Schema Cheat Sheet
https://github.com/sogko/graphql-schema-language-cheat-sheet
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02
Simple GraphQL Query Demo (I) - Mock
https://github.com/luisw19/graphql-samples/tree/master/graphql-
countries-part1
Query Operation {JSON}
[HTTP/POST]
GraphQL Endpoint
{
{
query
data {JSON} GraphQL Schema
}
}
http://.../graphiql
Graphiql
GraphQL Client GraphQL Service
GraphQL Server:
Browser Apollo/Express
22 @luisw19
Apollo Express: https://github.com/apollographql/apollo-server23
02
Simple GraphQL Query Demo (II) – REST Backend
https://github.com/luisw19/graphql-samples/tree/master/graphql-
countries-part2
[HTTP/GET]
https://restcountries.eu/rest/v2/{resource}
Query Operation {JSON}
[HTTP/POST]
GraphQL Endpoint REST COUNTRIES
{
{
data {JSON} {JSON}
query GraphQL Schema
}
}
Graphiql
GraphQL Client GraphQL Service
GraphQL Server:
Browser Apollo/Express
23 @luisw1924
02
Simple GraphQL Query Demo (III) - Mutation
https://github.com/luisw19/graphql-samples/tree/master/graphql-
countries-part3
[HTTP/GET]
https://restcountries.eu/rest/v2/{resource}
Query Operation {JSON}
[HTTP/POST]
GraphQL Endpoint REST COUNTRIES
{
{
data {JSON} {JSON}
query GraphQL Schema
}
} [HTTP/POST]
http://localhost:8000/{resource}
Graphiql
RequestBIN
GraphQL Client GraphQL Service
{JSON} Docker Container
GraphQL Server:
Browser Apollo/Express
24 @luisw1925
02
Simple GraphQL Query Demo (IV) – API Composition
Not merged yet… (soon)
[HTTP/GET]
https://restcountries.eu/rest/v2/{resource}
Query Operation {JSON}
[HTTP/POST]
GraphQL Endpoint REST COUNTRIES
{
{
data {JSON} {JSON}
query GraphQL Schema
}
}
[HTTP/POST]
Graphiql
https://www.google.co.uk/search?q={search}
GraphQL Client GraphQL Service
{JSON}
GraphQL Server:
Browser Apollo/Express
25 @luisw1926
03
GraphQL vs REST (++) Brilliant
(+) Good
(~) Neutral (it depends)
(-) Not very good
GraphQL REST (--) It sucks!
Developer Experience API Gateway API Composition
(design and consume APIs) (API routing, security, policies) (query data from multiple sources)
API
Design Build
API Gateway
Try
API API API
(-) Existing Gateways have rich
(++) Usage: Best usage experience (++) Perfectly suited for API
support for REST, not yet GraphQL -
for developers (Graphiql is brilliant!) composition. Each field can be fetch
but could be used. Alternative is to
(~) API-first design: Tooling evolving (in parallel) from any source in a
use a GraphQL Service as API
(build a service to mock). single query.
Gateway.
(~) Usage: depends on the quality of
(++) API Gateways take away from (--) The nature of REST makes it difficult
API definition and documentation
REST endpoints common tasks (e.g. to model resources that combine data
(+) API-first design: good tools
OAuth, API keys, throttling, structures from multiple sources. HATEOAS
available (e.g. Apiary, Swagger results in chattiness.
security).
Hub).
26 @luisw1927
03
GraphQL vs REST (++) Brilliant
(+) Good
(~) Neutral (it depends)
(-) Not very good
GraphQL REST (--) It sucks!
Authentication / Authorization Caching Versioning
Authorisation App
Client Server Cache
Network
Caching
1 Client
2 Resource Back
Resource End
(-) Standards like OAuth, OpenID (--) Network: unsuitable as there is
(++) Best practices are clear.
can be used however because all ops a common URL for all operations.
Versioning should be avoided and
can be accessed by single URI, (+) Service: possible based on
tools are provided (e.g. deprecation
custom authorisation is typically Object Type (even fields) and in
of fields) for continuous evolution.
required. mem cache like REDIS.
(++) Network: Caching is easy as
each resource is a unique URI.
(++) Major standards (OAuth 2, (-) Best practice less clear, in
Common tools can be used (e.g.
OpenId) supported by API Gateways practice URI based versioning very
CDNs).
and frameworks. popular although not encouraged.
(+) Service: It’s equally possible at
service Level.
27 @luisw1928
03
GraphQL vs REST (completely subjective!)
+++++++ (7) à But it will only improve!
GraphQL ~ (1)
---- (4)
++++++++ (8)
REST ~~ (2)
--- (3)
28 @luisw1904
Conclusions
Still early days but GraphQL has huge potential
GraphQL takes away many of the headaches of dealing with
1 REST from a client side -specially around complex queries
(against multiple sources). However tooling specially around
API Design and API Gateways is still evolving. So bear this in
mind when considering GraphQL.
GraphQL and REST can work nicely together
There are thousands of REST APIs (external and internal) and
2 REST still is a viable and popular option. Instead of boiling the
ocean, as Roy said, GraphQL is not necessarily a replacement
for REST. As shown in this presentation both can be
complementary and work together nicely.
There is no silver bullets –do your own research
3 There is tons of information available in the GraphQL
Communities page. Explore it, learn about it and adopt it
based on your own criteria and requirements. And hope this
presentation helps in the process!
29 © 2018 Capgemini. All rights reserved. @luisw19
2930
Resources
• GraphQL as an alternative approach to Rest recording at Devoxx’18 London
https://www.youtube.com/watch?v=hJOOdCPlXbU
• Github repository with the GraphQL tutorials
https://github.com/luisw19/graphql-samples
• Related articles:
• GraphQL with Oracle Database and node-oracledb by Christopher Jones
https://blogs.oracle.com/opal/demo%3a-graphql-with-node-oracledb
• GraphQL+OracleDB by Steven B
https://github.com/cloudsolutionhubs/oracledb-graphql-demo
30 @luisw19About Capgemini
With more than 190,000 people, Capgemini is present in over 40 countries and
celebrates its 50th Anniversary year in 2018. A global leader in consulting, technology
and outsourcing services, the Group reported 2016 global revenues of EUR 12.5 billion.
Together with its clients, Capgemini creates and delivers business, technology and
digital solutions that fit their needs, enabling them to achieve innovation and
competitiveness. A deeply multicultural organization, Capgemini has developed its own
way of working, the Collaborative Business Experience™, and draws on Rightshore®, its
worldwide delivery model.
Learn more about us at
www.capgemini.com
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