Apache Sling as an OSGi-powered REST middleware - Robert Munteau

http://robert.muntea.nu @rombert

Apache Sling as a RESTful API gateway for your NoSQL datastores

Apache Sling as a RESTful API gatewayfor your NoSQL datastores

Robert Munteanu, Adobe SystemsEclipseCon Europe 2015

http://robert.muntea.nu/


Who I am

$DAYJOB Adobe Experience

Manager Apache Sling Apache Jackrabbit Apache Felix

FOSS Apache Sling MantisBT Mylyn Connector for

MantisBT Mylyn Connector for Review

Board



Agenda

● Quick facts and figures● Meet Barry● Demo● Why is Sling such a good fit for an API gateway● Conclusions, Resources, Q&A



Apache Sling - History

2007Incubation

2009TLP

2015Version 8

200xPre-Apache



High-level View of the Code

Source: OpenHub



Level of activity

Source: OpenHub

Source: status.apache.org



Conceptual foundations

REST-basedContent-driven

OSGi-powered

Scripting InsideApache



REST-based

/content/blog/

/content/blog/{0}.html

/

BlogViewController

BlogListController

HomeController

SlingMainServlet//content/content/blog/content/blog/hello-world



REST-based

//content/content/blog/content/blog/hello-world

[sling/redirect][sling/redirect]

[blog/welcome][blog/page]



Barry – Senior Buzzword Deliverer



Demo time!



How is everything mapped?

/ ( root )

/content/blog/comments

/content/blog/posts/content/blog/images



How does Sling manage this?

ResourceProvider

JCR NoSQL FS

Couchbase MongoDB

ResourceProviderFactoryProduces



SPI → API

ResourceProviderFactory

OSGi Service Registry

ResourceResolver

Registers Gets



ResourceResolver

Resource getResource(String path);

Iterable<Resource> getChildren(Resource parent);

Iterator<Resource> findResources(String query, String language);

Resource create(Resource parent, String name, Map<String, Object> properties) throws PersistenceException;

void delete(Resource resource) throws PersistenceException;

void commit() throws PersistenceException;



How do I get to handle a Resource?

1 GET /content/blog/posts/hello_world.json

2 ResourceResolver.resolve(...)

3 ServletResolver.resolveServlet(...)3

4 servlet.doGet(...)



What do clients see out of this?

Resource res = request.getResource();

// 1. reading ...

ValueMap properties = ↵ res.getValueMap();

String title = properties.get(“jcr:title”,↵ “Missing”);

Post post = res.adaptTo(Post.class);

title = post.getTitle();



Why do we need adaptTo?

Adaptable

Resource ValueMap

Map<String,Object> Post



What do clients see out of this?

Resource res = request.getResource();

// 2. writing ...

ValueMap properties = ↵ res.adaptTo(ValueMap.class);

String title = properties.put(“jcr:title”,↵ “Hello, world”);

Post post = res.adaptTo(Post.class);

post.setTitle(“Hello, world”);

res.getResourceResolver().commit();



Demo time!


Oh, but there's more



More features

● Eventing, Thread Pooling, Job Management, Caching● Scripting: Groovy, Scala, JSP, Sightly, Java, Ruby, Thymeleaf● Flexible resource rendering with resource types● Very extensible due to being internally powered by OSGi – most extension points available to clients



Beyond the NoSQL datastores



Buzzword checklist

✔ RESTful✔ API gateway ✔ NoSQL✔ OSGi



Resources

● Apache Sling – http://sling.apache.org● Sling NoSQL providers - http://sling.apache.org/documentation/bundles/nosql-resource-providers.html● Apache Jackrabbit Oak - http://jackrabbit.apache.org/oak/



Resources


http://sling.apache.org/

http://sling.apache.org/documentation/bundles/nosql-resource-providers.html

http://sling.apache.org/documentation/bundles/nosql-resource-providers.html

http://jackrabbit.apache.org/oak/

Apache Sling as an OSGi-powered REST middleware - Robert Munteau

Technology

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