Introduce `Environment.matchesProfiles()` for profile expressions

[garretwilson]

I noticed that you've deprecated Environment.acceptsProfiles(String... profiles) in favor of a method that takes a Profile instance.

I can guess at the motivations behind this, but you might not have considered that this will cause problems in environments where it's easier to work with strings. (After all, profiles start out identified by strings.) For example, in Thymeleaf I might want to only include something if the active profile is production, as explained on Stack Overflow:

<div th:if="${#arrays.contains(@environment.getActiveProfiles(),'production')}">
     This is the production profile
</div>

If you eventually remove Environment.acceptsProfiles(String... profiles), this sort of thing will become more difficult.

Can you suggest an alternative in Thymeleaf?

Otherwise, you might want to reconsider deprecating this method.

[sbrannen]

Indeed, Environment.acceptsProfiles(String...) has been deprecated since Spring Framework 5.1; however, we have not yet indicated an intent to remove it in a particular release.

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In any case, a quick search online reveals that you should be able to use th:with to invoke static methods like org.springframework.core.env.Profiles.of(String...).

@garretwilson, does the following work for you?

<div
  th:with="profiles=${T(org.springframework.core.env.Profiles).of('production')}" 
  th:if="${@environment.acceptsProfiles(profiles)}">
     This is the production profile
</div>

[garretwilson]

Hi. Thanks for the quick response. For my simple page (providing debug information), the deprecated method was working. I posted this ticket not so much to help me, but to help the community by notifying the Spring team of implications of deprecation.

As for my case, I'll have to try the example you gave. I'm not sure when I'll be back in that area of code. But sincerely, it looks a bit ugly and verbose. It's getting close to including actual code in my Thymeleaf page, which we want to stay away from. Needing to create a Profile value class instance from the template negates some of the benefits of the template.

Sure, maybe Thymeleaf needs to create a facility to recognize value classes with .of(String) static factory methods and recognize them in constructors and wrap them automatically. But that's quite a task and would need to be pushed down into their expression language library. Who knows when that would or could happen.

As for me I'll just continue to use the deprecated approach for now, especially if you don't intend to remove it. I just prefer not to use deprecated methods. Here I may remove it for production anyway.

But I could imagine many circumstances in which I would want to do something in Thymeleaf based upon the profile. I wouldn't want to advocate that the team use deprecated methods. But I also wouldn't be really happy if they started sticking in that huge chunk of logic (which they would invariably have to look up anyway; no one could remember it without practice) just to check the profile. You see what I mean?

[sbrannen]

Hi @garretwilson,

Thanks for the feedback, and yes, I see what you mean.

When I posted that "workaround", I knew it was ugly and not user-friendly. My goal was to determine if it would be possible to achieve the same thing in Thymeleaf (and other similar scenarios) if we did actually remove that deprecated method at some point.

Regarding the deprecated method, it was deprecated in 5.1 in conjunction with #17063. The original (now deprecated) method only supports OR semantics; whereas, the new method supports profile expressions. Thus, the goal was to encourage people to use the more powerful profile expressions instead of the limited OR support.

That remains the goal, and in light of that I plan to introduce a method similar to the following in Environment.

default boolean acceptsProfiles(String profileExpression) {
	return acceptsProfiles(Profiles.of(profileExpression));
}

That should then support either of the following scenarios in Thymeleaf.

Single Profile

<div th:if="${@environment.acceptsProfiles('production')}">
     This is the production profile
</div>

Profile Expression

<div th:if="${@environment.acceptsProfiles('production & cloud')}">
     This is the production 'profile and cloud' profile
</div>

I am therefore repurposing this issue to introduce the new acceptsProfiles(String profileExpression) default method in Environment.