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/*
* =============================================================================
*
* Copyright (c) 2011-2018, The THYMELEAF team (http://www.thymeleaf.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* =============================================================================
*/
package org.thymeleaf.spring5.context;
import org.springframework.context.ApplicationContext;
import org.thymeleaf.context.IExpressionContext;
import org.thymeleaf.context.ITemplateContext;
import org.thymeleaf.spring5.expression.IThymeleafEvaluationContext;
import org.thymeleaf.spring5.expression.ThymeleafEvaluationContext;
import org.thymeleaf.spring5.naming.SpringContextVariableNames;
/**
*
* Utility class for easy access of information stored at the context in a Spring-enabled application
* (such as the Spring ApplicationContext).
*
*
* @author Daniel Fernández
*
* @since 3.0.3
*
*/
public class SpringContextUtils {
/**
*
* This is the name of the model attribute that will hold the (asychronously resolved)
* {@code WebSession} object in order to be used whenever needed, avoiding the need to block
* for obtaining it from the {@code ServerWebExchange}.
*
*
* Note resolving the {@code WebSession} from the reactive {@code Mono} stream does
* mean the creation of a {@code WebSession} instance, but not the real creation of a persisted session
* sent to the browser.
*
*
* Value: {@code "thymeleafWebSession"}
*
*
* @see org.springframework.web.server.WebSession
*/
public static final String WEB_SESSION_ATTRIBUTE_NAME = "thymeleafWebSession";
/**
*
* Get the {@link ApplicationContext} from the Thymeleaf template context.
*
*
* Note that the application context might not be always accessible (and thus this method
* can return {@code null}). Application Context will be accessible when the template is being executed
* as a Spring View, or else when an object of class {@link ThymeleafEvaluationContext} has been
* explicitly set into the {@link ITemplateContext} {@code context} with variable name
* {@link ThymeleafEvaluationContext#THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME}.
*
*
* @param context the template context.
* @return the application context, or {@code null} if it could not be accessed.
*/
public static ApplicationContext getApplicationContext(final ITemplateContext context) {
if (context == null) {
return null;
}
// The ThymeleafEvaluationContext is set into the model by ThymeleafView (or wrapped by the SPEL evaluator)
final IThymeleafEvaluationContext evaluationContext =
(IThymeleafEvaluationContext) context.getVariable(ThymeleafEvaluationContext.THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME);
if (evaluationContext == null || !(evaluationContext instanceof ThymeleafEvaluationContext)) {
return null;
}
// Only when the evaluation context is a ThymeleafEvaluationContext we can access the ApplicationContext.
// The reason is it could also be a wrapper on another EvaluationContext implementation, created at the
// SPELVariableExpressionEvaluator on-the-fly (where ApplicationContext is not available because there might
// even not exist one), instead of at ThymeleafView (where we are sure we are executing a Spring View and
// have an ApplicationContext available).
return ((ThymeleafEvaluationContext)evaluationContext).getApplicationContext();
}
/**
*
* Get the {@link IThymeleafRequestContext} from the Thymeleaf context.
*
*
* The returned object is a wrapper on the Spring request context that hides the fact of this request
* context corresponding to a Spring WebMVC or Spring WebFlux application.
*
*
* This will be done by looking for a context variable called
* {@link SpringContextVariableNames#THYMELEAF_REQUEST_CONTEXT}.
*
*
* @param context the context
* @return the thymeleaf request context
*/
public static IThymeleafRequestContext getRequestContext(final IExpressionContext context) {
if (context == null) {
return null;
}
return (IThymeleafRequestContext) context.getVariable(SpringContextVariableNames.THYMELEAF_REQUEST_CONTEXT);
}
private SpringContextUtils() {
super();
}
}