Add UriComponentsBuilder.clone() [SPR-12494]

[spring-projects-issues]

Hendy Irawan opened SPR-12494 and commented

In Spring MVC it's possible to inject UriComponentsBuilder into a @RestController method, making building links convenient.

However, when crafting a hypermedia response, there needs to be many links, some of them may refer to different places.

Calling .replacePath() (or any method) will mutate the UriComponentsBuilder, rendering it somewhat useless for next invocations. Also, it's impossible to start "clean" (from state of injection).

Please add clone() so it's easy for this use case.

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Affects: 4.1.2

Referenced from: commits 189ec75

[spring-projects-issues]

Rossen Stoyanchev commented

UriComponentsBuilder injectionion is a convenience that's relatively easy to forgo. I'm wondering if simply calling ServletUriComponentsBuilder would work alright for you?

If I understand this what you'd like:

@RequestMapping
public void handle(UriComponentsBuilder originalBuilder) {

	UriComponentsBuilder builder = originalBuilder.clone();
	// use builder...

	builder = originalBuilder.clone();
	// user builder...

}

which can be done as follows:

@RequestMapping
public void handle() {

	UriComponentsBuilder builder = ServletUriComponentsBuilder.fromCurrentServletMapping();
	// use builder

	builder = ServletUriComponentsBuilder.fromCurrentServletMapping();
	// user builder
}

It's bit longer but a private helper method (perhaps even in a base class) should help:

@RequestMapping
public void handle() {

	UriComponentsBuilder builder = createUriComponentsBuilder();
	// use builder

	builder = createUriComponentsBuilder();
	// user builder
}

// In some base class...		

protected UriComponentsBuilder createUriComponentsBuilder() {
	return ServletUriComponentsBuilder.fromCurrentServletMapping();
}

[spring-projects-issues]

Hendy Irawan commented

Thanks Rossen! Now I know where it comes from... :)

even createUriComponentsBuilder() is still longer than b.clone(), but at least now I have an alternative.

b.clone() feels cleaner to me :) and also, it will work for various other purposes, not just this one

[spring-projects-issues]

Rossen Stoyanchev commented

Alright, I've added clone() to UriComponentsBuilder hierarchy.

[spring-projects-issues]

Hendy Irawan commented

Thank you! :)