com.esri.geoportal.commons.robots.BotsParser.java Source code

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Here is the source code for com.esri.geoportal.commons.robots.BotsParser.java

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/* See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * Esri Inc. licenses this file to You 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.esri.geoportal.commons.robots;

import static com.esri.geoportal.commons.utils.Constants.DEFAULT_REQUEST_CONFIG;
import static com.esri.geoportal.commons.utils.CrlfUtils.formatForLog;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;

/**
 * Parser of "robots.txt" file.
 */
public class BotsParser {

    private static final Logger LOG = LoggerFactory.getLogger(BotsParser.class);

    private final BotsConfig botsConfig;
    private final HttpClient httpClient;

    /**
     * Gets default instance.
     *
     * @param botsConfig bots configuration
     * @param httpClient http client
     * @return instance
     */
    public static BotsParser getInstance(BotsConfig botsConfig, HttpClient httpClient) {
        String userAgent = botsConfig.getUserAgent();

        LOG.info(String.format("Creating default RobotsTxtParser :: user-agent: %s", userAgent));

        return new BotsParser(botsConfig, httpClient);
    }

    /**
     * Creates instance of the parser.
     * @param botsConfig bots config
     * @param httpClient http client
     */
    /*package*/ BotsParser(BotsConfig botsConfig, HttpClient httpClient) {
        this.botsConfig = botsConfig;
        this.httpClient = httpClient;
    }

    /**
     * Gets user agent.
     *
     * @return user agent
     */
    public String getUserAgent() {
        return botsConfig.getUserAgent();
    }

    /**
     * Parses context of the Robots.txt file if available.
     *
     * @param matchingStrategy matching strategy
     * @param winningStrategy winning strategy
     * @param serverUrl url of the server which is expected to have robots.txt
     * present
     * @return instance of {@link Bots} or <code>null</code> if unable to
     * obtain robots.txt
     */
    public Bots readRobotsTxt(MatchingStrategy matchingStrategy, WinningStrategy winningStrategy,
            String serverUrl) {
        if (serverUrl != null) {
            try {
                return BotsParser.this.readRobotsTxt(matchingStrategy, winningStrategy, new URL(serverUrl));
            } catch (MalformedURLException ex) {
                LOG.warn(String.format("Invalid server url: %s", serverUrl), ex);
            }
        }
        return null;
    }

    /**
     * Parses context of the Robots.txt file if available.
     *
     * @param matchingStrategy matching strategy
     * @param winningStrategy winning strategy
     * @param serverUrl url of the server which is expected to have robots.txt
     * present
     * @return instance of {@link Bots} or <code>null</code> if unable to
     * obtain robots.txt
     */
    public Bots readRobotsTxt(MatchingStrategy matchingStrategy, WinningStrategy winningStrategy, URL serverUrl) {
        if (serverUrl != null) {
            LOG.info(formatForLog("Accessing robots.txt for: %s", serverUrl.toExternalForm()));
            try {
                URL robotsTxtUrl = getRobotsTxtUrl(serverUrl);
                if (robotsTxtUrl != null) {
                    HttpGet method = new HttpGet(robotsTxtUrl.toExternalForm());
                    method.setConfig(DEFAULT_REQUEST_CONFIG);
                    method.setHeader("User-Agent", botsConfig.getUserAgent());
                    HttpResponse response = httpClient.execute(method);
                    if (response.getStatusLine().getStatusCode() < 300) {
                        InputStream responseStream = response.getEntity().getContent();
                        Bots robots = BotsParser.this.readRobotsTxt(matchingStrategy, winningStrategy,
                                responseStream);
                        if (robots != null) {
                            LOG.info(formatForLog("Received Robotx.txt for: %s", serverUrl.toExternalForm()));
                        }
                        return robots;
                    }
                }
            } catch (IOException ex) {
                LOG.debug(formatForLog("Unable to access robots.txt for: %s", serverUrl.toExternalForm()));
                LOG.debug("", ex);
            }
        }
        return null;
    }

    /**
     * Parses robots TXT
     *
     * @param matchingStrategy matching strategy
     * @param winningStrategy winning strategy
     * @param robotsTxt stream of data
     * @return instance or RobotsTxt or <code>null</code>
     */
    public Bots readRobotsTxt(MatchingStrategy matchingStrategy, WinningStrategy winningStrategy,
            InputStream robotsTxt) {
        Bots robots = null;

        try (BotsReader reader = new BotsReader(getUserAgent(), matchingStrategy, winningStrategy, robotsTxt);) {
            robots = reader.readRobotsTxt();
        } catch (IOException ex) {
            LOG.warn("Unable to parse robots.txt", ex);
            return null;
        }

        return robots;
    }

    private URL getRobotsTxtUrl(URL baseUrl) {
        try {
            if (baseUrl != null) {
                if (baseUrl.getPort() >= 0) {
                    return new URL(String.format("%s://%s:%d/robots.txt", baseUrl.getProtocol(), baseUrl.getHost(),
                            baseUrl.getPort()));
                } else {
                    return new URL(String.format("%s://%s/robots.txt", baseUrl.getProtocol(), baseUrl.getHost()));
                }
            }
        } catch (MalformedURLException ex) {
            LOG.warn("Invalid robots.txt url.", ex);
        }
        return null;
    }
}