com.antonjohansson.managementcenter.core.web.VaadinResourcesServlet.java Source code

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Here is the source code for com.antonjohansson.managementcenter.core.web.VaadinResourcesServlet.java

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/**
 * Copyright (c) Anton Johansson <antoon.johansson@gmail.com>
 *
 * 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.antonjohansson.managementcenter.core.web;

import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;
import static org.apache.commons.io.IOUtils.copy;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.Objects;
import java.util.Optional;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Serves static Vaadin resources.
 *
 * @author Anton Johansson
 */
public class VaadinResourcesServlet extends HttpServlet {
    private static final String CONTEXT = "/management-center";

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String name = getRequestURI(request);
        Optional<URL> resource = getResource(name);

        if (!resource.isPresent()) {
            response.sendError(SC_NOT_FOUND);
            return;
        }

        try (InputStream input = resource.get().openStream(); OutputStream output = response.getOutputStream()) {
            copy(input, output);
        }
    }

    private String getRequestURI(HttpServletRequest request) {
        String requestURI = request.getRequestURI();
        if (requestURI.startsWith(CONTEXT)) {
            requestURI = requestURI.substring(CONTEXT.length());
        }
        return requestURI;
    }

    private Optional<URL> getResource(String name) {
        return WebActivator.vaadinBundles().map(b -> b.getResource(name)).filter(Objects::nonNull).findAny();
    }
}