Micronaut - Get Running environment name in the view - thymeleaf

Question

I have a small Micronaut application with a view layer (thymeleaf). Now I want to integrate Google Analytics or some other tracking tool. Of course this should be just loaded in production mode but how can I do a check for the environment in the view layer?
I start the application in the following way:
java -Dmicronaut.environments=prod -jar mywebsite.jar

Answer 1

You can inject the io.micronaut.context.env.Environment and pass the result of getActiveNames() as part of your view model
EDIT:
If you want to add this data to each model without touching each controller method you can add a server filter that happens before the view filter to manipulate the response, or create a piece of around advice that can manipulate the return value of the controller.

Answer 2

Another approach to solving this problem is to utilise #Replaces annotation to override ThymeleafViewsRenderer class and add common data in your class.
import io.micronaut.context.annotation.Replaces
import io.micronaut.context.env.Environment
import io.micronaut.core.beans.BeanMap
import io.micronaut.core.io.Writable
import io.micronaut.core.io.scan.ClassPathResourceLoader
import io.micronaut.core.util.ArgumentUtils
import io.micronaut.http.HttpRequest
import io.micronaut.views.exceptions.ViewRenderingException
import io.micronaut.views.thymeleaf.ThymeleafViewsRenderer
import io.micronaut.views.thymeleaf.WebContext
import org.thymeleaf.TemplateEngine
import org.thymeleaf.context.Context
import org.thymeleaf.context.IContext
import org.thymeleaf.exceptions.TemplateEngineException
import org.thymeleaf.templateresolver.AbstractConfigurableTemplateResolver
import javax.annotation.Nonnull
import javax.annotation.Nullable
import javax.inject.Inject
import javax.inject.Singleton
#Singleton
#Replaces(bean = ThymeleafViewsRenderer.class)
class CustomThymeleafFilter extends ThymeleafViewsRenderer {
CustomThymeleafFilter(AbstractConfigurableTemplateResolver templateResolver, TemplateEngine templateEngine, ClassPathResourceLoader resourceLoader) {
super(templateResolver, templateEngine, resourceLoader)
}
#Inject
Environment environment
#Override
#Nonnull
public Writable render(#Nonnull String viewName, #Nullable Object data) {
ArgumentUtils.requireNonNull("viewName", viewName);
return (writer) -> {
//following block adds environments variable to model
Map dataMap = variables(data)
dataMap.put("environment", environment.activeNames)
IContext context = new Context(Locale.US, dataMap);
processView(viewName, writer, context);
};
}
#Override
#Nonnull
public Writable render(#Nonnull String viewName, #Nullable Object data,
#Nonnull HttpRequest<?> request) {
ArgumentUtils.requireNonNull("viewName", viewName);
ArgumentUtils.requireNonNull("request", request);
return (writer) -> {
//following block adds environments variable to model
Map dataMap = variables(data)
dataMap.put("environment", environment.activeNames)
IContext context = new WebContext(request, Locale.US, dataMap);
processView(viewName, writer, context);
};
}
private static Map<String, Object> variables(#Nullable Object data) {
if (data == null) {
return new HashMap<>();
}
if (data instanceof Map) {
return (Map<String, Object>) data;
} else {
return BeanMap.of(data);
}
}
private void processView(String viewName, Writer writer, IContext context) {
try {
engine.process(viewName, context, writer);
} catch (TemplateEngineException e) {
throw new ViewRenderingException("Error rendering Thymeleaf view [" + viewName + "]: " + e.getMessage(), e);
}
}
}