Provide a way to enable streaming mode via annotations (and eventually app config) [SPR-15103]

[spring-projects-issues]

Sébastien Deleuze opened SPR-15103 and commented

Like implemented on the functional framework via #19597, we should support a way to set hints potentially via a dedicated annotation (currently only the special case of @JsonView is supported). That could be used to customize the flushing strategy (#19547).

---

Issue Links:

• Progressive HTML rendering support [SPR-14981] #19547 Progressive HTML rendering support
• Possible performance issue in the generation of JSON in Spring Web Reactive [SPR-15095] #19662 Possible performance issue in the generation of JSON in Spring Web Reactive
• Provide a way to specify hints in the functional web API [SPR-15030] #19597 Provide a way to specify hints in the functional web API
• Add support for JSON Streaming [SPR-15104] #19671 Add support for JSON Streaming

[spring-projects-issues]

Sébastien Deleuze commented

I suggest @Hint(key = "foo", value = ...) + using Java 8 repeating annotations (since multiple hints could be provided). That would be consistent with what we did on the functional API side (#19597). This should be supported at @RequestBody and @ResponseBody level.

[spring-projects-issues]

Arjen Poutsma commented

With a @Hint annotation as described, users would not be able to set create hints dynamically in the method controller itself. Not sure if that is an issue, but worth noting.

[spring-projects-issues]

Sébastien Deleuze commented

Indeed, I tend to think that's a limitation we can live with but good point.

Another alternative to fulfill #19671 and #19547 is to provide more high level annotation or use existing annotation attibutes like @RequestBody or ResponseBody ones.

[spring-projects-issues]

Sébastien Deleuze commented

Resolving this as won't do because we decided to control streaming using media type, see #19671 and this commit for more details.