Sling Servlets

https://sling.apache.org/documentation/the-sling-engine/servlets.html

Sling Servlets are defined as OSGi services of type javax.servlet.Servlet.
In order to create a Sling Servlet, one of the following classes should be extended:

Class	Usage
SlingAllMethodsServlet	Servlet implementation that responds to all HTTP methods. These are primarily used to surface endpoints that respond to POST (and GET) Requests.
SlingSafeMethodsServlet	This class is intended for applications where data is only read. It supports only GET requests.
AbstractPredicateServlet	Retrieves the predicates from the request.

Servlets can be registered in two ways:

1.   Using path

2.   Using resource type

Java annotation to register a servlet:

1) @SlingServlet(
< Property1>={“values”},
<Property2>={“values”},
…………
)

2)

@Component(metatype = true)

@Service(Servlet.class)

@Properties({

    @Property(name = "sling.servlet.resourceTypes", value = "sling/servlet/default"),

    @Property(name = "sling.servlet.selectors", value = "hello"),

    @Property(name = "sling.servlet.extensions", value = "html"),

    @Property(name = "sling.servlet.methods", value = "GET")

})

Servlets registered by Path:

Service Reference Properties	Description	Way to define	Note
sling.servlet.path	registering the servlet by path	paths={“/a/b”}	For a Servlet registered as an OSGi service to be used by the Sling Servlet Resolver, either or both of the sling.servlet.paths or the sling.servlet.resourceTypes service reference properties must be set. If neither is set, the Servlet service is ignored.

Servlets registered by resource type:

Service Reference Properties	Description	Way to define	Note
sling.servlet.resourceTypes	registering the servlet by resource type	resourceTypes = {“cq:Page”},	If a value for sling.servlet.paths is specified, this is ignored.
sling.servlet.selectors	Filter servlet by selector,	selectors = {“test”}	This property is ignored if the sling.servlet.paths property is set.
sling.servlet.extensions	Filter servlet by extension	extensions = {“xml”}	This property is ignored if the sling.servlet.paths property is set.
sling.servlet.methods		methods = {“GET”, “POST”}	This property is ignored if thesling.servlet.paths property is set. If this property is missing, the value defaults to GET, regardless of which methods are actually implemented/handled by the servlet.
sling.servlet.prefix