org.springframework.web.servlet.theme.CookieThemeResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.servlet.theme;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.ThemeResolver;
import org.springframework.web.util.CookieGenerator;
import org.springframework.web.util.WebUtils;
/**
* {@link ThemeResolver} implementation that uses a cookie sent back to the user
* in case of a custom setting, with a fallback to the default theme.
* This is particularly useful for stateless applications without user sessions.
*
* Custom controllers can thus override the user's theme by calling
* {@code setThemeName}, e.g. responding to a certain theme change request.
*
* @author Jean-Pierre Pawlak
* @author Juergen Hoeller
* @since 17.06.2003
* @see #setThemeName
*/
public class CookieThemeResolver extends CookieGenerator implements ThemeResolver {
/**
* The default theme name used if no alternative is provided.
*/
public static final String ORIGINAL_DEFAULT_THEME_NAME = "theme";
/**
* Name of the request attribute that holds the theme name. Only used
* for overriding a cookie value if the theme has been changed in the
* course of the current request! Use RequestContext.getTheme() to
* retrieve the current theme in controllers or views.
* @see org.springframework.web.servlet.support.RequestContext#getTheme
*/
public static final String THEME_REQUEST_ATTRIBUTE_NAME = CookieThemeResolver.class.getName() + ".THEME";
/**
* The default name of the cookie that holds the theme name.
*/
public static final String DEFAULT_COOKIE_NAME = CookieThemeResolver.class.getName() + ".THEME";
private String defaultThemeName = ORIGINAL_DEFAULT_THEME_NAME;
public CookieThemeResolver() {
setCookieName(DEFAULT_COOKIE_NAME);
}
/**
* Set the name of the default theme.
*/
public void setDefaultThemeName(String defaultThemeName) {
this.defaultThemeName = defaultThemeName;
}
/**
* Return the name of the default theme.
*/
public String getDefaultThemeName() {
return this.defaultThemeName;
}
@Override
public String resolveThemeName(HttpServletRequest request) {
// Check request for preparsed or preset theme.
String themeName = (String) request.getAttribute(THEME_REQUEST_ATTRIBUTE_NAME);
if (themeName != null) {
return themeName;
}
// Retrieve cookie value from request.
String cookieName = getCookieName();
if (cookieName != null) {
Cookie cookie = WebUtils.getCookie(request, cookieName);
if (cookie != null) {
String value = cookie.getValue();
if (StringUtils.hasText(value)) {
themeName = value;
}
}
}
// Fall back to default theme.
if (themeName == null) {
themeName = getDefaultThemeName();
}
request.setAttribute(THEME_REQUEST_ATTRIBUTE_NAME, themeName);
return themeName;
}
@Override
public void setThemeName(
HttpServletRequest request, @Nullable HttpServletResponse response, @Nullable String themeName) {
Assert.notNull(response, "HttpServletResponse is required for CookieThemeResolver");
if (StringUtils.hasText(themeName)) {
// Set request attribute and add cookie.
request.setAttribute(THEME_REQUEST_ATTRIBUTE_NAME, themeName);
addCookie(response, themeName);
}
else {
// Set request attribute to fallback theme and remove cookie.
request.setAttribute(THEME_REQUEST_ATTRIBUTE_NAME, getDefaultThemeName());
removeCookie(response);
}
}
}