scala 如何在 Play 2.x 中检测应用程序模式
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How to detect application mode in Play 2.x
提问by kes
From within a Play 2.1 application, how would I programmatically determine which mode the application is running in (i.e., Developmentvs. Production)?
在 Play 2.1 应用程序中，我将如何以编程方式确定应用程序在哪种模式下运行（即Development与Production）？
For example, it would be useful to be able to do something like this from inside a template:
例如，能够从模板内部执行以下操作会很有用：
<p>@if(__some_play_API_call__ == Dev) { <b>Development mode</b> }</p>
<p>@if(__some_play_API_call__ == Dev) { <b>Development mode</b> }</p>
In the Play 2.0 API documentation, there appears to be a modeproperty of the play.api.Applicationclass... however, I am unsure about how to get at the instanceof the currently running application.
在 Play 2.0 API 文档中，似乎有一个类的mode属性......但是，我不确定如何获取当前正在运行的应用程序的实例。play.api.Application
回答by maxmc
You can access the current Appliction via
您可以通过以下方式访问当前应用程序
play.api.Play.current()
to find out the mode try
找出模式尝试
play.api.Play.current().mode()
or simply use
或者干脆使用
play.api.Play.isDev(play.api.Play.current())
回答by koppor
In Play 2.5.x the play.Play.isDev()method is deprecated, one has to use dependency injection:
在 Play 2.5.x 中，该play.Play.isDev()方法已弃用，必须使用依赖注入：
import javax.inject.Inject;
public class Example {
@Inject
private play.Environment environment;
public void myMethod() {
if (environment.isDev()) {
...
}
}
}
Or equivalently in Scala:
或者在 Scala 中等效：
class ErrorHandler @Inject()(environment: Environment) {
def myMethod() = {
if (environment.isDev) {
...
}
}
}
environment.isDev()returns a Boolean, which one can easily pass to a template. No need to use implicit variables as described here.
environment.isDev()返回一个布尔值，可以轻松地将其传递给模板。无需使用此处所述的隐式变量。
回答by pme
With Play 2.5, Play 2.6and Play 2.7
使用Play 2.5、Play 2.6和 Play 2.7
You can do it like this:
你可以这样做：
import play.Environment
class MyController @Inject()(env: Environment) {
println(s"DevMode is ${env.isDev}")
println(s"ProdMode is ${env.isProd}")
println(s"TestMode is ${env.isTest}")
}
Or in Play 2.6and Play 2.7you have also the version with play.api.Environment:
或者在Play 2.6和 Play 2.7 中，您还有以下版本play.api.Environment：
import play.api.Environment
class MyController @Inject()(env: Environment) {
println(s"ProdMode is ${env.mode == Mode.Prod}")
println(s"DevMode is ${env.mode == Mode.Dev}")
println(s"TestMode is ${env.mode == Mode.Test}")
}
For both the Scala Doc states:
对于 Scala Doc 状态：
/**
* The environment for the application.
*
* Captures concerns relating to the classloader and the filesystem for the application.
*/
回答by Gus
In play 2.3.X you can also check via:
在 play 2.3.X 中，您还可以通过以下方式检查：
play.Play.isProd()
play.Play.isDev()
play.Play.isTest()
回答by icl7126
In Play 2.5 using Scala there is a context.environment.modevalue of Enumerationfrom play.api.Modewith one of the values Dev, Test, Prod.
For compile time dependency injection you have contextavailable in your app loader and if you extend BuiltInComponentsFromContextthen you can use (inject) directly environment.mode
在使用 Scala 的 Play 2.5 中，有一个fromcontext.environment.mode值，其中一个值是。
对于编译时依赖注入，您可以在应用程序加载器中使用，如果您扩展，则可以直接使用 (inject)Enumerationplay.api.ModeDev, Test, ProdcontextBuiltInComponentsFromContextenvironment.mode
回答by Jonik
In Play 2.6, inject an Environmentinstance and use its modefield: one of play.api.Modeenum values.
在Play 2.6 中，注入一个Environment实例并使用其mode字段：play.api.Mode枚举值之一。
import javax.inject.Inject
import play.api.Environment
import play.api.Mode.Prod
import play.api.mvc.{AbstractController, ControllerComponents}
class TestController @Inject()(cc: ControllerComponents, env: Environment)
extends AbstractController(cc) {
def hello = Action {
if (env.mode == Prod) {
??????// ...
}
Ok(s"Hello world in ${env.mode} mode")
}
}
At least in Play 2.6.20, the methods env.isDev, env.isProd, etc, mentioned by pme, no longer work.
至少在 Play 2.6.20中， pme 提到的方法env.isDev、env.isProd等不再有效。
