GraphQL Introduction
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This document introduces GraphQL, describing what it is and isn't. It explains that GraphQL is not a query language like SQL, but rather specifies fields that can be resolved through code. The document provides examples of GraphQL schemas, queries, and mutations. It also discusses GraphQL integration with various technologies like Relay and Java libraries. Finally, it demonstrates GraphQL tooling like GraphiQL and an example DX integration.
GraphQL Introduction
- 1. 1 GraphQL Introduction Serge Huber, Jahia CTO shuber@jahia.com #graphql Make some noise
- 2. WHAT IS GRAPHQL ? …and what it isn’t.
- 3. 3 WHAT IS GRAPHQL ? I like opposites It 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 still happening
- 4. 4 WHAT IS GRAPHQL ? A (very) quick look Courtesy of the GraphQL.org home page
- 5. 5 WHAT IS GRAPHQL ? Some users Courtesy of the GraphQL.org home page See more on http://graphql.org/users
- 6. 6 WHAT IS GRAPHQL ? A quick demo https://www.graphqlhub.com
- 7. 7 WHAT IS GRAPHQL ? Schemas • A schema that describes: • Objects • Object fields • Field arguments & directives • Interfaces • Unions
- 8. 8 WHAT IS GRAPHQL ? Fields, the key to understanding GraphQL ! A field may be: • a static value • a value resolved through code Field may have: • Arguments that are like parameters to a method call • Constraints to filter data • Directives that make the field conditional in the result Don’t think of fields as variables, think of them as methods !
- 9. 9 WHAT IS GRAPHQL ? Queries • Queries • Specify what fields are part of the result • Only fields specified in the schema are acceptable • Field may be the result of computations • Fields may specify arguments that will constrain the results (such as id:10) • Directives may also be used (such as @include) • Variables may be used • Fragments • Type casts ! • Pagination (Relay schema)
- 10. 10 WHAT IS GRAPHQL ? Mutations • Mutations • Make it possible to write/modify data • Very similar syntax to queries
- 11. 11 WHAT IS GRAPHQL ? Compared to REST APIs REST GraphQL Specifies URL structure YES NO Specifies request / response body structure NO YES Validation NO YES Requires a declared schema NO YES Key-Value friendly YES NO Extra (non CRUD) methods standardized NO YES
- 12. GRAPHQL INTEGRATION Mapping to existing stuff
- 13. 13 GRAPHQL INTEGRATION Typical architecture Client Server React / React Native Relay GraphQL Data & Services
- 15. 15 GRAPHQL INTEGRATION Angular 2 and Relay https://tech.small-improvements.com/2016/02/25/angular-2-and-relay/
- 16. 16 GRAPHQL INTEGRATION Java Libraries • graphql-java : Java implementation of GraphQL • graphql-java-servlet : A relay-compatible OSGI Java servlet • graphql-java-annotations : Can generate GraphQL schemas from Pojo annotations !
- 17. GRAPHQL TOOLING What there’s tooling already ?
- 19. 19 GRAPHQL TOOLING GraphiQL Features • Auto-completion based on GraphQL schema • Execution of GraphQL queries and mutations • Input of variables • Result viewer • Built-in documentation browser
- 20. 20 GRAPHQL TOOLING GraphQLHub A hub to test public GraphQL services such as : • Hacker News • Reddit • GitHub • Twitter • Giphy • Relay-compatible Key- Value store But (strangely) not Facebook (probably because of API keys)
- 21. 21 GRAPHQL TOOLING Awesome GraphQL Best list of tools & libraries at : https://github.com/chentsulin/awesome-graphql Some cool examples: SQL Libraries • GraphpostgresQL - GraphQL for Postgres. • sql-to-graphql - Generate a GraphQL API based on your SQL database structure. • PostGraphQL - A GraphQL schema created by reflection over a PostgreSQL schema.
- 22. DX INTEGRATION DEMO You’re not serious are you ?
- 23. 23 DX INTEGRATION DEMO The source Project 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 mutation providers ! • Dynamic schema, re-generated every time a new mutation or query provider is registered 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 up and refactoring • Mapping to JCR content still to be defined.
- 24. 24 QUESTIONS AND ANSWERS Ask away, don’t be shy
- 25. 25 shuber@jahia.com THANK YOU FOR LISTENING