Support groovy template engine in webflux [SPR-15850]

[spring-projects-issues]

Jason Yu opened SPR-15850 and commented

Support groovy template engine just like spring web mvc. It would be nice to write domain-specific code via groovy markup builder.

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No further details from SPR-15850

[spring-projects-issues]

Jason Yu commented

I plan to develop this feature. Before I open pull request, What things should I pay attention to?

[spring-projects-issues]

Jason Yu commented

I have migrated implementation from WebMVC to WebFlux and pull request opened. Could this issue be solved in RC4? If I want to use groovy template via spring boot, I need to open a relative issue on GitHub’s integrated issue tracking system of spring boot?

[spring-projects-issues]

Brian Clozel commented

Could this be contributed as a third party project?

With Spring 5, we've chosen to keep the Freemarker support as a reference implementation - but let templating engines support their own infrastructure (see this comment). Many projects like Thymeleaf thrive without an "official" support provided by the Framework itself.

I'd be happy to provide feedback on the PR if you're considering moving it to its own project.

[spring-projects-issues]

Jason Yu commented

I see your point, I will try to open relative issue on Groovy's Jira. But I not sure Groovy's contributor willing to implement groovy template for Spring 5 just like thymeleaf-spring5 package or not.

[spring-projects-issues]

Brian Clozel commented

Indeed, groovy itself may not be the best place. Maybe a separate project?

[spring-projects-issues]

Jason Yu commented

I have no idea. Please let me know if you have any suggestions.

[spring-projects-issues]

Jason Yu commented

As result, If no one want to do that. I may open a own project for it. So you can close this issue, thanks.

[spring-projects-issues]

Brian Clozel commented

Alright, thanks for the update.

Just one tip about your current PR. DataBuffer are low level constructs, and can be pooled - this is why we need to allocate/release them.
You can release a DataBuffer instance in two ways:

1. if everything goes well, by writing it to the exchange response; the releasing will be done for you when the buffer is written on the network
2. by releasing it manually; this is required if it's not written to the response. In your implementation, if an exception happens while rendering the template, you have to call DataBufferUtils.release(buffer);.

Let me know if/when you create that project. I'll happily review the implementation. Thanks for your contribution!

[spring-projects-issues]

Jason Yu commented

Cool, thanks for your tip. I will survey thymleaf-spring5 and spring-boot 2 first.