Server Sent Events

[dsyer]

Maybe I missed it, but I didn't see any support for SSE. HTMX has it built into the client side, and Spring has SSE support on the server side, so it might make sense to try and include it here?

[wimdeblauwe]

I don't know what this library should offer about SSE? I have used SSE with Spring and htmx succesfully already.

[wimdeblauwe]

The app is a Spring servlet application where I added the spring-boot-starter-webflux dependency just for pushing stuff over SSE. My other controller methods are not using Flux or Mono.

I now tried with adding @Import({CompositeViewRenderer.class, ThymeleafReactiveViewResolver.class}) to my application but that does not help.

Will it only work in a "webflux only" application?

If I am not able to use the ServerSentEvent abstraction, then how is it possible to set the event name?

[dsyer]

It needs to be a webflux app to use that specific component. I had one for MVC as well (in a branch) but I’m not sure it works with SSE. I’m sure it could be fixed.

I see what you mean about the event name. I never needed to set it, so it wasn’t a concern, but I see that it should be.

[wimdeblauwe]

What I did now to be able to use a Thymeleaf fragment in my Server-sent event is the following:

. Inject an instance of org.thymeleaf.spring6.SpringTemplateEngine into my controller
. Use templateEngine.process("my-template", Set.of("my-fragment"), context).replaceAll("\n", "\ndata:")

I add the needed variables for the fragment to the Context object.

The replaceAll is needed because the Thymeleaf fragment has newlines.

Once you know it, it is not that bad, but if you know of better ways, I am always eager to learn :)

[checketts]

That would be worth documenting in the readme

[wimdeblauwe]

Not sure if it really belongs in the readme of this library, but it would sure make a good blog post. I'll also add it to my upcoming book on using htmx with Thymeleaf.