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vaadin-framework
peilaus alkaen https://github.com/vaadin/framework.git


			
				
					
						
						
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							/*
 * Copyright 2000-2018 Vaadin Ltd.
 *
 * 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.vaadin.server;

import java.io.IOException;
import java.io.Writer;

/**
 * A {@link RequestHandler} that presents an informative page if the browser in
 * use is unsupported. Recognizes Chrome Frame and allow it to be used.
 *
 * <p>
 * This handler is usually added to the application by
 * {@link LegacyCommunicationManager}.
 * </p>
 */
@SuppressWarnings("serial")
public class UnsupportedBrowserHandler extends SynchronizedRequestHandler {

    /** Cookie used to ignore browser checks. */
    public static final String FORCE_LOAD_COOKIE = "vaadinforceload=1";

    @Override
    public boolean synchronizedHandleRequest(VaadinSession session,
            VaadinRequest request, VaadinResponse response) throws IOException {

        // Check if the browser is supported
        // If Chrome Frame is available we'll assume it's ok
        WebBrowser b = session.getBrowser();
        if (b.isTooOldToFunctionProperly() && !b.isChromeFrameCapable()) {
            // bypass if cookie set
            String c = request.getHeader("Cookie");
            if (c == null || !c.contains(FORCE_LOAD_COOKIE)) {
                response.setNoCacheHeaders();
                writeBrowserTooOldPage(request, response);
                return true; // request handled
            }
        }

        return false; // pass to next handler
    }

    /**
     * Writes a page encouraging the user to upgrade to a more current browser.
     *
     * @param request
     * @param response
     * @throws IOException
     */
    protected void writeBrowserTooOldPage(VaadinRequest request,
            VaadinResponse response) throws IOException {
        try (Writer page = response.getWriter()) {
            WebBrowser b = VaadinSession.getCurrent().getBrowser();

            // @formatter:off
            page.write(
                    "<html>"
                            + "<head>"
                            + "  <style>"
                            + "    html {"
                            + "      background: #fff;"
                            + "      color: #444;"
                            + "      font: 400 1em/1.5 \"Helvetica Neue\", Roboto, \"Segoe UI\", sans-serif;"
                            + "      padding: 2em;"
                            + "    }"
                            + "    body {"
                            + "      margin: 2em auto;"
                            + "      width: 27em;"
                            + "      max-width: 100%;"
                            + "    }"
                            + "    h1 {"
                            + "      line-height: 1.1;"
                            + "      margin: 2em 0 1em;"
                            + "      color: #000;"
                            + "      font-weight: 400;"
                            + "    }"
                            + "    em {"
                            + "      font-size: 1.2em;"
                            + "      font-style: normal;"
                            + "      display: block;"
                            + "      margin-bottom: 1.2em;"
                            + "    }"
                            + "    p {"
                            + "      margin: 0.5em 0 0;"
                            + "    }"
                            + "    a {"
                            + "      text-decoration: none;"
                            + "      color: #007df0;"
                            + "    }"
                            + "    sub {"
                            + "      display: block;"
                            + "      margin-top: 2.5em;"
                            + "      text-align: center;"
                            + "      border-top: 1px solid #eee;"
                            + "      padding-top: 2em;"
                            + "    }"
                            + "    sub,"
                            + "    small {"
                            + "      color: #999;"
                            + "    }"
                            + "  </style>"
                            + "</head>"
                            + "<body><h1>I'm sorry, but your browser is not supported</h1>"
                            + "<p>The version (" + b.getBrowserMajorVersion()
                            + "." + b.getBrowserMinorVersion()
                            + ") of the browser you are using "
                            + " is outdated and not supported.</p>"
                            + "<p>You should <b>consider upgrading</b> to a more up-to-date browser.</p> "
                            + "<p>The most popular browsers are <b>"
                            + " <a href=\"https://www.google.com/chrome\">Chrome</a>,"
                            + " <a href=\"http://www.mozilla.com/firefox\">Firefox</a>,"
                            + (b.isWindows()
                                    ? " <a href=\"http://windows.microsoft.com/en-US/internet-explorer/downloads/ie\">Internet Explorer</a>,"
                                    : "")
                            + " <a href=\"http://www.opera.com/browser\">Opera</a>"
                            + " and <a href=\"http://www.apple.com/safari\">Safari</a>.</b><br/>"
                            + "Upgrading to the latest version of one of these <b>will make the web safer, faster and better looking.</b></p>"
                            + (b.isIE()
                                    ? "<script type=\"text/javascript\" src=\"http://ajax.googleapis.com/ajax/libs/chrome-frame/1/CFInstall.min.js\"></script>"
                                            + "<p>If you can not upgrade your browser, please consider trying <a onclick=\"CFInstall.check({mode:'overlay'});return false;\" href=\"http://www.google.com/chromeframe\">Chrome Frame</a>.</p>"
                                    : "")
                            + "<p><sub><a onclick=\"document.cookie='"
                            + FORCE_LOAD_COOKIE
                            + "';window.location.reload();return false;\" href=\"#\">Continue without updating</a> (not recommended)</sub></p>"
                            + "</body>\n" + "</html>");
            // @formatter:on
        }
    }
}