GraphQL in Apache Sling - but isn't it the opposite of REST?
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The document discusses the integration of GraphQL within the Apache Sling framework, highlighting its capabilities for creating dynamic, resource-oriented web applications. It covers topics such as GraphQL schema generation, server-side and client-side rendering, and the use of fetcher services for data handling. The presentation concludes that GraphQL is a powerful query language that complements REST APIs in web development.
![GraphQL in Apache Sling - Bertrand Delacrétaz September 2020
Default SchemaProvider
14
$ curl http://localhost:8080/content/articles/culture.GQLschema
type Query {
section: Section @fetcher(name:"website/currentResource")
navigation: Navigation @fetcher(name:"website/navigation")
}
type Navigation {
root: String
sections: [Section]
previous: String
next: String
search: String
}
...
Full power of the Sling rendering
pipeline for resource-specific
schemas.
The @fetcher directive points to
SlingDataFetcher services.](https://image.slidesharecdn.com/apachecon-2020-graphql-rest-bertrand-201001180839/85/GraphQL-in-Apache-Sling-but-isn-t-it-the-opposite-of-REST-14-320.jpg)
GraphQL in Apache Sling - but isn't it the opposite of REST?
- 1. GraphQL in Apache Sling... but isn't it the opposite of REST? Bertrand Delacrétaz :: Principal Scientist, Adobe Board Member, Apache :: @bdelacretaz Images are from stock.adobe.com unless otherwise specified - slides revision: 2020-09-28
- 2. What's Apache Sling? ?
- 3. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 3 Content Repository Resource Resolver Scripting and Rendering Script Resolver Resource ScriptRequest Output The Sling HTTP Request Processing Pipeline 1 2 3 4 sling:include content aggregation! 3 A dynamic Resource-oriented Java and OSGi-based Web Applications Framework
- 5. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 5 Query with the same "shape" as the output JSON. Also: Mutations and Subscriptions POST to server returns JSON output with just what you need.
- 6. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 GraphQL Schema 6 In our case, the schema is generated from an internal Sling request to <resource>.GQLschema So it can be specific to a given sling:resourceType
- 7. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 GraphQL Schema Introspection 7 The schema information helps us build this query:
- 9. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 Sling-samples GraphQL website demo 9 Both server-side and client-side rendering use GraphQL and Handlebars. GraphiQL and similar clients supported out-of-the-box. Clean JSON rendering available via GraphQL. Server-side (GraphQL + hbs) Client-side (GraphQL + hbs) sling-samples/ org.apache.sling.graphql.samples.website Client-side queries
- 10. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 Client-side query + rendering 10 GraphQL Servlet Content Repository Client Sling Server POST GraphQL query JSON results -> Handlebars
- 11. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 Client Sling Server 11 GraphQL Script Engine Content Repository Sling Scripts Resolver article.hbs script Handlebars Script Engine Internal Request <path>.GQLSchema json.GQL script Server-side query + rendering The Handlebars engine renders the .json output of the GraphQL query GET article.html Internal Request <path>.json HTML
- 13. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 Sling GraphQL Core 0.0.4 13 API Script Engine Servlet Internally uses https://github.com/graphql-java/graphql-java package o.a.s.graphql.core.api
- 14. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 Default SchemaProvider 14 $ curl http://localhost:8080/content/articles/culture.GQLschema type Query { section: Section @fetcher(name:"website/currentResource") navigation: Navigation @fetcher(name:"website/navigation") } type Navigation { root: String sections: [Section] previous: String next: String search: String } ... Full power of the Sling rendering pipeline for resource-specific schemas. The @fetcher directive points to SlingDataFetcher services.
- 15. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 SlingDataFetcher 15 Java: SlingDataFetcher OSGi service, returns a Map or POJO Server-side script: selected by fetcher name, returns a Map
- 16. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 16 Sling GraphQL Core Request Handling Schema Acquisition graphql-java parsing + delegation www.graphql-java.com Content Repository Other Data Sources Under the hood: performance? SlingDataFetcher Services Data Acquisition + Processing Caching? Client Sling Server Performance Happens Here -> Schema Generation (Sling Request Processing)
- 17. Caching?
- 18. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 HTTP-friendly caching? 18 Queries Store GraphQL Servlet Default POST-based interaction is generally not cacheable. POST query text 201 Created -> /p/bc6f GET /p/bc6f 200 OK -> query results + Cache-Control headers Stored Query Text Client Sling Server future requests can start here:
- 19. GraphQL and REST, BFFs ?
- 20. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 GraphQL and REST (+ RPC?) 20 Quoting Phil Sturgeon, builder of API design tools, https://phil.tech/2017/graphql-vs-rest-overview/ We do need queries, but also caching, hypertext, scalability. GraphQL is certainly better than a badly designed so-called REST API...and it's a great query API.
- 21. CODA
- 22. GraphQL in Apache Sling - Bertrand Delacrétaz September 2020 CODA GraphQL is a very nice query language that also looks useful on the server-side. It's not better or worse than REST: different animals that can play well together! I'm @bdelacretaz - thank you! Code at https://github.com/apache/sling-org-apache-sling-graphql-core/ Fun text by https://github.com/apache/sling-whiteboard/tree/master/fake-content-generator 22 The Sling GraphQL Core is V0.0.4: patches welcome! Internal Sling requests FTW!