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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.spring4.expression;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.expression.BeanFactoryResolver;
import org.springframework.context.expression.MapAccessor;
import org.springframework.core.convert.ConversionService;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.expression.spel.support.StandardTypeConverter;
import org.thymeleaf.expression.IExpressionObjects;
import org.thymeleaf.standard.expression.RestrictedRequestAccessUtils;
import org.thymeleaf.standard.expression.StandardExpressionObjectFactory;
import org.thymeleaf.util.Validate;
/**
*
* Thymeleaf's basic implementation of the {@link IThymeleafEvaluationContext} interface, which in turn extends
* from Spring's {@link org.springframework.expression.EvaluationContext} interface.
*
*
* This implementation adds Thymeleaf's own property accessors
* (see {@link org.springframework.expression.PropertyAccessor}) for accessing
* the {@link org.thymeleaf.context.IContext} object in which variables are stored.
*
*
* Also, this evaluation context (which is usually instanced at the
* {@link org.thymeleaf.spring4.view.ThymeleafView} initialization) links the execution of expressions
* with the available {@link BeanFactory} and {@link ConversionService} instances, used during evaluation.
*
*
* Before executing a Spring EL expression using this evaluation context, it should be enriched with the
* variables to be made accessible (like {@code #variableName}), using a
* {@link ThymeleafEvaluationContextWrapper} object.
*
*
* @author Daniel Fernández
*
* @since 2.1.0
*
*/
public final class ThymeleafEvaluationContext
extends StandardEvaluationContext
implements IThymeleafEvaluationContext {
public static final String THYMELEAF_EVALUATION_CONTEXT_CONTEXT_VARIABLE_NAME = "thymeleaf::EvaluationContext";
private static final MapAccessor MAP_ACCESSOR_INSTANCE = new MapAccessor();
private final ApplicationContext applicationContext;
private IExpressionObjects expressionObjects = null;
private boolean variableAccessRestricted = false;
public ThymeleafEvaluationContext(final ApplicationContext applicationContext, final ConversionService conversionService) {
super();
Validate.notNull(applicationContext, "Application Context cannot be null");
// ConversionService CAN be null
this.applicationContext = applicationContext;
this.setBeanResolver(new BeanFactoryResolver(applicationContext));
if (conversionService != null) {
this.setTypeConverter(new StandardTypeConverter(conversionService));
}
this.addPropertyAccessor(SPELContextPropertyAccessor.INSTANCE);
this.addPropertyAccessor(MAP_ACCESSOR_INSTANCE);
}
public ApplicationContext getApplicationContext() {
return this.applicationContext;
}
@Override
public Object lookupVariable(final String name) {
if (this.expressionObjects != null && this.expressionObjects.containsObject(name)) {
final Object result = this.expressionObjects.getObject(name);
if (result != null) {
// We need to first check if we are in a restricted environment. If so, restrict access to the request.
if (this.variableAccessRestricted &&
(StandardExpressionObjectFactory.REQUEST_EXPRESSION_OBJECT_NAME.equals(name) ||
StandardExpressionObjectFactory.HTTP_SERVLET_REQUEST_EXPRESSION_OBJECT_NAME.equals(name))) {
return RestrictedRequestAccessUtils.wrapRequestObject(result);
}
return result;
}
}
// fall back to superclass
return super.lookupVariable(name);
}
public boolean isVariableAccessRestricted() {
return this.variableAccessRestricted;
}
public void setVariableAccessRestricted(final boolean restricted) {
this.variableAccessRestricted = restricted;
}
public IExpressionObjects getExpressionObjects() {
return this.expressionObjects;
}
public void setExpressionObjects(final IExpressionObjects expressionObjects) {
this.expressionObjects = expressionObjects;
}
}