Add native support for Jstachio

[SentryMan]

I'm thinking of something like

@Controller("/widgets")
public class WidgetController {
  private final HelloComponent hello;
  public WidgetController(HelloComponent hello) {
    this.hello = hello;
  }

  @Get("/{id}")
  HelloWorld getById(int id) {
    //...
  }

  @JStache(
      template =
          """
          {{#people}}
          {{.}}! You are
          {{#-last}}
          That is all for now!
          {{/-last}}
          {{/people}}
          """)
  public record HelloWorld(List<String> people) {}
}

we should read the jstache annotation and generate something like

@Generated("avaje-helidon-generator")
@Component
public class WidgetController$Route implements HttpFeature {

  private final WidgetController controller;

  public WidgetController$Route(WidgetController controller) {
    this.controller = controller;
  }

  @Override
  public void setup(HttpRouting.Builder routing) {
    routing.get("/widgets/{id}", this::_getById);
  }

  private void _getById(ServerRequest req, ServerResponse res) throws Exception {
    res.status(OK_200);
    var pathParams = req.path().pathParameters();
    var id = asInt(pathParams.contains("id") ? pathParams.get("id") : null);
    var result = controller.getById(id);
    res.send(Jstachio.render(result)); // or the generated renderer if running in zero dependency mode
  }
}

[rbygrave]

My gut says we typically desire res.headers().contentType(HTML_UTF8); with templates so I think we should move @Html from htmx-api to http-api. This can be put on the controller to indicate the default content produced is html.

So then, when we set a @Jstache annotation on a response type of a @Html controller, then we generate the res.headers().contentType(HTML_UTF8);.

The question then is around content caching [will this mess with content caching] ... and currently I think that is ok, because currently we use an explicit @ContentCache on the method to indicate the content cache handling code should also be generated.

So yes, I think what you are suggesting is a good idea and I think we can extend it at some point to support the content caching stuff we have with htmx-nima.

Background details follow ....

---

Background details

Hmm, so I'm fairly actively using htmx & Jstache using the current approach provided by avaje-htmx-nima-jstache and that approach allows for that 1 extra layer of indirection to allow for content caching (and string/html content lends itself nicely to content caching)

So we'd have a method like:

  @ContentCache
  @HxRequest(target = "name")
  @Get("name/{id}")
  ViewName getById(int id) {
    ...;
  }

The current generated code that includes content caching this looks like:

  private void _getById(ServerRequest req, ServerResponse res) throws Exception {
    res.status(OK_200);
    var key = contentCache.key(req);
    var cacheContent = contentCache.content(key);
    if (cacheContent != null) {
      res.headers().contentType(HTML_UTF8);
      res.send(cacheContent);
      return;
    }
    var pathParams = req.path().pathParameters();
    var id = asInt(pathParams.contains("id") ? pathParams.get("id") : null);
    var result = controller.getById(id);

    if (result == null) {
      res.status(NO_CONTENT_204).send();
    } else {
      var content = renderer.render(result);
      contentCache.contentPut(key, content);
      res.headers().contentType(HTML_UTF8);
      res.send(content);
    }
  }

So my thoughts are:

• Yeah we could do what you are suggesting here
• I think we should move the @Html annotation from htmx-api to http-api to get the Content-Type bit
• We can leave out the @ContentCache + associated API [TemplateContentCache, TemplateRenderer] for now ... and let that stay in htmx-nima for a bit longer to prove out the design there

[SentryMan]

@html controller

what use is an HTML annotation when we already know that any object annotated with a Jstache annotation is a template?

[rbygrave]

what use is an HTML annotation when

I believe you mean ... Why don't we just default the content type to HTML when we know its Jstache? Right?

edit:
As in, we only need to be more explicit when (A) using something other than Jstache? (B) it isn't actually rendering html but some other text content

[SentryMan]

I believe you mean ... Why don't we just default the content type to HTML when we know its Jstache? Right?

Essentially, yes

(B) it isn't actually rendering html but some other text content

one could just use the produces annotation to override the default if rendering some other text content

[rbygrave]

Yes, I agree, i think defaulting to html for Jstache content will work very well in practice - lets do that!!