PolledExternalService

An external HTTP service that is kept up-to-date by polling.

A PolledExternalService may be composed of one or more PolledHTTPResources, each of which describes a single endpoint and how to poll it.

Implements

• ExternalService

Constructors

new PolledExternalService()

new PolledExternalService(resources): PolledExternalService

Construct a polled external service.

Parameters

Parameter	Type	Description
resources	{}	Specification(s) of external resource(s) to poll

Returns

PolledExternalService

Methods

shutdown()

shutdown(): Promise<void>

Shutdown the external service.

Returns

Promise<void>

Implementation of

ExternalService.shutdown

---

subscribe()

subscribe(
   instance, 
   resourceName, 
   params, 
   callbacks): Promise<void>

Subscribe to a resource provided by the external service.

Parameters

Parameter	Type	Description
instance	string	Instance identifier of the external resource.
resourceName	string	-
params	Json	Parameters of the external resource.
callbacks	{ error: (error) => void; update: (updates, isInit) => Promise<void>; }	Callbacks to react on error/update.
callbacks.error	(error) => void	Error callback to log the error that prevent an idermetiate update.
callbacks.update	(updates, isInit) => Promise<void>	Update callback.

Returns

Promise<void>

Implementation of

ExternalService.subscribe

---

unsubscribe()

unsubscribe(instance): void

Unsubscribe from a resource provided by the external service.

Parameters

Parameter	Type	Description
instance	string	Instance identifier of the external resource.

Returns

void

Implementation of

ExternalService.unsubscribe