Package nl.b3p.tailormap.api.controller.admin

Class ServerSentEventsAdminController

java.lang.Object

nl.b3p.tailormap.api.controller.admin.ServerSentEventsAdminController

@RestController
public class ServerSentEventsAdminController
extends Object

Constructor Summary

Constructors

Constructor	Description
ServerSentEventsAdminController(ch.rasc.sse.eventbus.SseEventBus eventBus, com.fasterxml.jackson.databind.ObjectMapper objectMapper)

Method Summary

Modifier and Type	Method	Description
org.springframework.web.servlet.mvc.method.annotation.SseEmitter	entityEvents(String clientId)	Endpoint for the single-page admin frontend to receive updates to entities from other windows.
void	keepAlive()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ServerSentEventsAdminController

public ServerSentEventsAdminController(ch.rasc.sse.eventbus.SseEventBus eventBus,
                                       com.fasterxml.jackson.databind.ObjectMapper objectMapper)

Method Detail

entityEvents

@GetMapping(path="${tailormap-api.admin.base-path}/events/{clientId}")
public org.springframework.web.servlet.mvc.method.annotation.SseEmitter entityEvents(@PathVariable("clientId")
                                                                                     String clientId)

Endpoint for the single-page admin frontend to receive updates to entities from other windows. The frontend does not load all data on each navigation as a traditional frontend and loads and stores entities in memory. This requires updating stale entities when these get updated in other windows (from other sessions or the same session in a different browser tab), otherwise data might get lost or overwritten.

This endpoint uses Server-sent events, which technically is a long-poll HTTP request which allows unidirectional server-initiated communication. Not bidirectional like websockets, but simpler because of the long-poll HTTP request. The webserver should ideally use HTTP/2 or higher because HTTP/1.1 limits the amount of simultaneous connections to a server per browser to 6.

Returns:

the server-sent events emitter

keepAlive

@Scheduled(fixedRate=60000L)
public void keepAlive()
               throws com.fasterxml.jackson.core.JsonProcessingException

Throws:

com.fasterxml.jackson.core.JsonProcessingException