GraphQL Introduction

Serge Huber

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1.1GraphQL IntroductionSerge Huber, Jahia CTOshuber@jahia.com#graphqlMake some noise
2.WHAT IS GRAPHQL ?…and what it isn’t.
3.3WHAT IS GRAPHQL ?I like oppositesIt is not:• A query language like SQL, JCR-SQL, etc…• A URL specification• A finalized standard• A standard submitted to a standards body• A 100% JSON standard• A mature standard, changes are stillhappening
4.4WHAT IS GRAPHQL ?A (very) quick lookCourtesy of the GraphQL.org home page
5.5WHAT IS GRAPHQL ?Some usersCourtesy of the GraphQL.org home pageSee more on http://graphql.org/users
6.6WHAT IS GRAPHQL ?A quick demohttps://www.graphqlhub.com
7.7WHAT IS GRAPHQL ?Schemas• A schema that describes:• Objects• Object fields• Field arguments & directives• Interfaces• Unions
8.8WHAT IS GRAPHQL ?Fields, the key to understanding GraphQL !A field may be:• a static value• a value resolved through codeField may have:• Arguments that are likeparameters to a method call• Constraints to filter data• Directives that make the fieldconditional in the resultDon’t think of fields as variables,think of them as methods !
9.9WHAT IS GRAPHQL ?Queries• Queries• Specify what fields are part of theresult• Only fields specified in the schemaare acceptable• Field may be the result ofcomputations• Fields may specify arguments thatwill constrain the results (such asid:10)• Directives may also be used (such as@include)• Variables may be used• Fragments• Type casts !• Pagination (Relay schema)
10.10WHAT IS GRAPHQL ?Mutations• Mutations• Make it possible to write/modifydata• Very similar syntax to queries
11.11WHAT IS GRAPHQL ?Compared to REST APIsREST GraphQLSpecifies URL structure YES NOSpecifies request /response body structureNO YESValidation NO YESRequires a declaredschemaNO YESKey-Value friendly YES NOExtra (non CRUD) methodsstandardizedNO YES
12.GRAPHQL INTEGRATIONMapping to existing stuff
13.13GRAPHQL INTEGRATIONTypical architectureClientServerReact / React NativeRelayGraphQLData & Services
14.14GRAPHQL INTEGRATIONRelay
15.15GRAPHQL INTEGRATIONAngular 2 and Relayhttps://tech.small-improvements.com/2016/02/25/angular-2-and-relay/
16.16GRAPHQL INTEGRATIONJava Libraries• graphql-java : Java implementation of GraphQL• graphql-java-servlet : A relay-compatible OSGI Javaservlet• graphql-java-annotations : Can generate GraphQLschemas from Pojo annotations !
17.GRAPHQL TOOLINGWhat there’s tooling already ?
18.18GRAPHQL TOOLINGGraphiQL
19.19GRAPHQL TOOLINGGraphiQLFeatures• Auto-completion based on GraphQL schema• Execution of GraphQL queries and mutations• Input of variables• Result viewer• Built-in documentation browser
20.20GRAPHQL TOOLINGGraphQLHubA hub to test public GraphQLservices such as :• Hacker News• Reddit• GitHub• Twitter• Giphy• Relay-compatible Key-Value storeBut (strangely) not Facebook(probably because of APIkeys)
21.21GRAPHQL TOOLINGAwesome GraphQLBest list of tools & libraries at :https://github.com/chentsulin/awesome-graphqlSome cool examples:SQL Libraries• GraphpostgresQL - GraphQL for Postgres.• sql-to-graphql - Generate a GraphQL API based on your SQL databasestructure.• PostGraphQL - A GraphQL schema created by reflection over a PostgreSQLschema.
22.DX INTEGRATION DEMOYou’re not serious are you ?
23.23DX INTEGRATION DEMOThe sourceProject available here:http://www.github.com/Jahia/graphql-core-feature• Built as a Karaf features, requires DX 7.2 to run• Embeds GraphiQL as an administration UI !• Extensible through other modules, they simply provide query and mutationproviders !• Dynamic schema, re-generated every time a new mutation or query provider isregistered in the OSGi services registry• Based on the graphql-java-servlet project, available at:http://www.github.com/graphql/graphql-java-servlet• Still a lot to do, just beginning• Code is clearly a proof of concept prototype, lots of things will need cleaning upand refactoring• Mapping to JCR content still to be defined.
24.24QUESTIONS AND ANSWERSAsk away, don’t be shy
25.25shuber@jahia.comTHANK YOU FOR LISTENING