com.google.gerrit.httpd.raw.RobotsServlet.java Source code

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Here is the source code for com.google.gerrit.httpd.raw.RobotsServlet.java

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// Copyright (C) 2013 The Android Open Source Project
//
// 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.gerrit.httpd.raw;

import static java.nio.file.Files.exists;
import static java.nio.file.Files.isReadable;

import com.google.common.io.ByteStreams;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.config.SitePaths;
import com.google.inject.Inject;
import com.google.inject.Singleton;

import org.eclipse.jgit.lib.Config;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;

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

/**
 * This class provides a mechanism to use a configurable robots.txt file,
 * outside of the .war of the application. In order to configure it add the
 * following to the {@code httpd} section of the {@code gerrit.conf}
 * file:
 *
 * <pre>
 * [httpd]
 *         robotsFile = etc/myrobots.txt
 * </pre>
 *
 * If the specified file name is relative it will resolved as a sub directory of
 * the site directory, if it is absolute it will be used as is.
 *
 * If the specified file doesn't exist or isn't readable the servlet will
 * default to the {@code robots.txt} file bundled with the .war file of the
 * application.
 */
@SuppressWarnings("serial")
@Singleton
public class RobotsServlet extends HttpServlet {
    private static final Logger log = LoggerFactory.getLogger(RobotsServlet.class);

    private final Path robotsFile;

    @Inject
    RobotsServlet(@GerritServerConfig final Config config, final SitePaths sitePaths) {
        Path file = sitePaths.resolve(config.getString("httpd", null, "robotsFile"));
        if (file != null && (!exists(file) || !isReadable(file))) {
            log.warn("Cannot read httpd.robotsFile, using default");
            file = null;
        }
        robotsFile = file;
    }

    @Override
    protected void doGet(final HttpServletRequest req, final HttpServletResponse rsp) throws IOException {
        rsp.setContentType("text/plain");
        try (InputStream in = openRobotsFile(); OutputStream out = rsp.getOutputStream()) {
            ByteStreams.copy(in, out);
        }
    }

    private InputStream openRobotsFile() {
        if (robotsFile != null) {
            try {
                return Files.newInputStream(robotsFile);
            } catch (IOException e) {
                log.warn("Cannot read " + robotsFile + "; using default", e);
            }
        }
        return getServletContext().getResourceAsStream("/robots.txt");
    }
}