org.springframework.web.context.request.ServletRequestAttributes Maven / Gradle / Ivy
/*
* Copyright 2002-2019 the original author or authors.
*
* 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
*
* https://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.springframework.web.context.request;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.NumberUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.util.WebUtils;
/**
* Servlet-based implementation of the {@link RequestAttributes} interface.
*
* Accesses objects from servlet request and HTTP session scope,
* with no distinction between "session" and "global session".
*
* @author Juergen Hoeller
* @since 2.0
* @see javax.servlet.ServletRequest#getAttribute
* @see javax.servlet.http.HttpSession#getAttribute
*/
public class ServletRequestAttributes extends AbstractRequestAttributes {
/**
* Constant identifying the {@link String} prefixed to the name of a
* destruction callback when it is stored in a {@link HttpSession}.
*/
public static final String DESTRUCTION_CALLBACK_NAME_PREFIX =
ServletRequestAttributes.class.getName() + ".DESTRUCTION_CALLBACK.";
protected static final Set> immutableValueTypes = new HashSet<>(16);
static {
immutableValueTypes.addAll(NumberUtils.STANDARD_NUMBER_TYPES);
immutableValueTypes.add(Boolean.class);
immutableValueTypes.add(Character.class);
immutableValueTypes.add(String.class);
}
private final HttpServletRequest request;
@Nullable
private HttpServletResponse response;
@Nullable
private volatile HttpSession session;
private final Map sessionAttributesToUpdate = new ConcurrentHashMap<>(1);
/**
* Create a new ServletRequestAttributes instance for the given request.
* @param request current HTTP request
*/
public ServletRequestAttributes(HttpServletRequest request) {
Assert.notNull(request, "Request must not be null");
this.request = request;
}
/**
* Create a new ServletRequestAttributes instance for the given request.
* @param request current HTTP request
* @param response current HTTP response (for optional exposure)
*/
public ServletRequestAttributes(HttpServletRequest request, @Nullable HttpServletResponse response) {
this(request);
this.response = response;
}
/**
* Exposes the native {@link HttpServletRequest} that we're wrapping.
*/
public final HttpServletRequest getRequest() {
return this.request;
}
/**
* Exposes the native {@link HttpServletResponse} that we're wrapping (if any).
*/
@Nullable
public final HttpServletResponse getResponse() {
return this.response;
}
/**
* Exposes the {@link HttpSession} that we're wrapping.
* @param allowCreate whether to allow creation of a new session if none exists yet
*/
@Nullable
protected final HttpSession getSession(boolean allowCreate) {
if (isRequestActive()) {
HttpSession session = this.request.getSession(allowCreate);
this.session = session;
return session;
}
else {
// Access through stored session reference, if any...
HttpSession session = this.session;
if (session == null) {
if (allowCreate) {
throw new IllegalStateException(
"No session found and request already completed - cannot create new session!");
}
else {
session = this.request.getSession(false);
this.session = session;
}
}
return session;
}
}
private HttpSession obtainSession() {
HttpSession session = getSession(true);
Assert.state(session != null, "No HttpSession");
return session;
}
@Override
public Object getAttribute(String name, int scope) {
if (scope == SCOPE_REQUEST) {
if (!isRequestActive()) {
throw new IllegalStateException(
"Cannot ask for request attribute - request is not active anymore!");
}
return this.request.getAttribute(name);
}
else {
HttpSession session = getSession(false);
if (session != null) {
try {
Object value = session.getAttribute(name);
if (value != null) {
this.sessionAttributesToUpdate.put(name, value);
}
return value;
}
catch (IllegalStateException ex) {
// Session invalidated - shouldn't usually happen.
}
}
return null;
}
}
@Override
public void setAttribute(String name, Object value, int scope) {
if (scope == SCOPE_REQUEST) {
if (!isRequestActive()) {
throw new IllegalStateException(
"Cannot set request attribute - request is not active anymore!");
}
this.request.setAttribute(name, value);
}
else {
HttpSession session = obtainSession();
this.sessionAttributesToUpdate.remove(name);
session.setAttribute(name, value);
}
}
@Override
public void removeAttribute(String name, int scope) {
if (scope == SCOPE_REQUEST) {
if (isRequestActive()) {
removeRequestDestructionCallback(name);
this.request.removeAttribute(name);
}
}
else {
HttpSession session = getSession(false);
if (session != null) {
this.sessionAttributesToUpdate.remove(name);
try {
session.removeAttribute(DESTRUCTION_CALLBACK_NAME_PREFIX + name);
session.removeAttribute(name);
}
catch (IllegalStateException ex) {
// Session invalidated - shouldn't usually happen.
}
}
}
}
@Override
public String[] getAttributeNames(int scope) {
if (scope == SCOPE_REQUEST) {
if (!isRequestActive()) {
throw new IllegalStateException(
"Cannot ask for request attributes - request is not active anymore!");
}
return StringUtils.toStringArray(this.request.getAttributeNames());
}
else {
HttpSession session = getSession(false);
if (session != null) {
try {
return StringUtils.toStringArray(session.getAttributeNames());
}
catch (IllegalStateException ex) {
// Session invalidated - shouldn't usually happen.
}
}
return new String[0];
}
}
@Override
public void registerDestructionCallback(String name, Runnable callback, int scope) {
if (scope == SCOPE_REQUEST) {
registerRequestDestructionCallback(name, callback);
}
else {
registerSessionDestructionCallback(name, callback);
}
}
@Override
public Object resolveReference(String key) {
if (REFERENCE_REQUEST.equals(key)) {
return this.request;
}
else if (REFERENCE_SESSION.equals(key)) {
return getSession(true);
}
else {
return null;
}
}
@Override
public String getSessionId() {
return obtainSession().getId();
}
@Override
public Object getSessionMutex() {
return WebUtils.getSessionMutex(obtainSession());
}
/**
* Update all accessed session attributes through {@code session.setAttribute}
* calls, explicitly indicating to the container that they might have been modified.
*/
@Override
protected void updateAccessedSessionAttributes() {
if (!this.sessionAttributesToUpdate.isEmpty()) {
// Update all affected session attributes.
HttpSession session = getSession(false);
if (session != null) {
try {
for (Map.Entry entry : this.sessionAttributesToUpdate.entrySet()) {
String name = entry.getKey();
Object newValue = entry.getValue();
Object oldValue = session.getAttribute(name);
if (oldValue == newValue && !isImmutableSessionAttribute(name, newValue)) {
session.setAttribute(name, newValue);
}
}
}
catch (IllegalStateException ex) {
// Session invalidated - shouldn't usually happen.
}
}
this.sessionAttributesToUpdate.clear();
}
}
/**
* Determine whether the given value is to be considered as an immutable session
* attribute, that is, doesn't have to be re-set via {@code session.setAttribute}
* since its value cannot meaningfully change internally.
* The default implementation returns {@code true} for {@code String},
* {@code Character}, {@code Boolean} and standard {@code Number} values.
* @param name the name of the attribute
* @param value the corresponding value to check
* @return {@code true} if the value is to be considered as immutable for the
* purposes of session attribute management; {@code false} otherwise
* @see #updateAccessedSessionAttributes()
*/
protected boolean isImmutableSessionAttribute(String name, @Nullable Object value) {
return (value == null || immutableValueTypes.contains(value.getClass()));
}
/**
* Register the given callback as to be executed after session termination.
*
Note: The callback object should be serializable in order to survive
* web app restarts.
* @param name the name of the attribute to register the callback for
* @param callback the callback to be executed for destruction
*/
protected void registerSessionDestructionCallback(String name, Runnable callback) {
HttpSession session = obtainSession();
session.setAttribute(DESTRUCTION_CALLBACK_NAME_PREFIX + name,
new DestructionCallbackBindingListener(callback));
}
@Override
public String toString() {
return this.request.toString();
}
}