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= Reactive routing in Helidon MP
:description: Helidon MP reactive routing
= :keywords: helidon, rest, reactive, WebServer, route, routing

Since Helidon 1.4

== Configuring a reactive route in Helidon MP
Helidon MP Server will pick up CDI beans that implement the `io.helidon.webserver.Service`
interface and configure them with the underlying WebServer.

This allows configuration of reactive routes to run alongside a JAX-RS application.

The bean is expected to be either `ApplicationScoped` or `Dependent` and will be requested
only once during the boot of the `Server`.

The bean will support injection of `ApplicationScoped` and `Dependent` scoped beans.
You cannot inject `RequestScoped` beans. Please use WebServer features to handle request
related objects.

=== Customizing the reactive service
The service can be customized using annotations and/or configuration to be

- registered on a specific path
- registered with a named routing

==== Assigning a reactive service to named ports
Helidon has the concept of named routings. These correspond to the named ports
configured with WebServer.

You can assign a reactive service to a named routing (and as a result to a named port) using
either an annotation or configuration (or both to override the value from annotation).

===== Annotation `@RoutingName`
You can annotated a service with this annotation to assign it to a specific named routing,
that is (most likely) going to be bound to a specific port.

The annotation has two attributes:
- `value` that defines the routing name
- `required` to mark that the routing name MUST be configured in Helidon server

Example:
----
@ApplicationScoped
@RoutingName(value="admin", required="true")
@RoutingPath("/admin")
public class AdminService implements Service {
//....
}
----

The example above will be bound to `admin` routing (and port) and will fail if such a port
is not configured.

===== Configuration override of routing name
For each service class you can define the routing name and its required flag by specifying a configuration
option `class-name.routing-name.name` and `class-name.routing-name.required`.

Example (YAML) configuration for a class `io.helidon.examples.AdminService` that changes the
routing name to `management` and its required flag to `false`:

----
io.helidon.examples.AdminService:
  routing-name:
    name: "management"
    required: false
----

==== Configuring a reactive service path
Each service is registered on a path. If none is configured, then the service would be
configured on the root path.

You can configure service path using an annotation or configuration (or both to override value from annotation)

===== Annotation `@RoutingPath`
You can configure `@RoutingPath` to define the path a service is registered on.

===== Configuration override of routing path
For each reactive service class you can define the routing path by specifying a configuration
option `class-name.routing-path.path`.

Example (YAML) configuration for a class `io.helidon.example.AdminService` that changes the
routing path to `/management`:

----
io.helidon.examples.AdminService:
  routing-path:
    path: "/management"
----

=== Example configuration of reactive service
A full configuration example (YAML):

----
server:
  port: 8080
  sockets:
    management:
      port: 8090

io.helidon.examples.AdminService:
  routing-name:
    name: "management"
    required: true
  routing-path:
    path: "/management"
----
