com.google.gwt.core.server.GwtServletBase Maven / Gradle / Ivy
/*
* Copyright 2012 Google Inc.
*
* 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 com.google.gwt.core.server;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Base servlet for GWT server-side code which extracts properties from the
* request and sets them for this thread.
*
* For now, subclasses should override {@link #init()} and set the locale
* configuration fields - eventually this will be read from a deploy artifact.
*/
public class GwtServletBase extends HttpServlet {
// These defaults should be kept in sync with I18N.gwt.xml
protected String[] localeSearchOrder = new String[] {
"queryparam", "cookie", "meta", "useragent",
};
protected String defaultLocale = "default";
protected String localeCookie = null;
protected String localeQueryParam = "locale";
@Override
public void init() throws ServletException {
// TODO(jat): implement reading config from a deploy artifact
}
/**
* Fetch a cookie from the HTTP request.
*
* @param req
* @param cookieName
* @return the value of the cookie or null if not found
*/
protected final String getCookie(HttpServletRequest req, String cookieName) {
Cookie[] cookies = req.getCookies();
if (cookies == null) {
return null;
}
for (Cookie cookie : cookies) {
if (cookie.getName().equals(cookieName)) {
return cookie.getValue();
}
}
return null;
}
/**
* Get the GWT locale to use from this request.
*
* @param req
* @return the GWT locale to use as a String
*/
protected String getGwtLocale(HttpServletRequest req) {
// set the locale
String locale = null;
for (String localeMethod : localeSearchOrder) {
if ("cookie".equals(localeMethod)) {
if (localeCookie != null) {
locale = getCookie(req, localeCookie);
}
} else if ("queryparam".equals(localeMethod)) {
if (localeQueryParam != null) {
locale = req.getParameter(localeQueryParam);
}
} else if ("useragent".equals(localeMethod)) {
// TODO(jat): implement Accept-Language processing
} else if ("usemeta".equals(localeMethod)) {
// ignored on the server
} else {
// TODO(jat): log ignored method?
}
if (locale != null) {
return locale;
}
}
return defaultLocale;
}
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException,
IOException {
setGwtProperties(req);
super.service(req, resp);
}
/**
* Sets all GWT properties from the request.
*
* If this method is overridden, this version should be called first and then
* any modifications to property values should be done.
*
* @param req
*/
protected void setGwtProperties(HttpServletRequest req) {
ServerGwtBridge.getInstance().setThreadProperty("locale", getGwtLocale(req));
// TODO(jat): other properties, such as user.agent?
}
}