com.panforge.robotstxt.RobotsTxtImpl Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of robots Show documentation
Java package used to read, parse and query robots.txt
There is a newer version: 1.4.6
/*
 * Copyright 2016 Piotr Andzel.
 *
 * 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.panforge.robotstxt;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.net.URI;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Robots TXT implementation.
 */
class RobotsTxtImpl implements RobotsTxt {

  private Group defaultSection;
  private final List groups = new ArrayList<>();

  private Integer crawlDelay;
  private String host;
  private final List sitemaps = new ArrayList<>();

  private final MatchingStrategy matchingStrategy;
  private final WinningStrategy winningStrategy;

  /**
   * Creates instance of the RobotsTxt implementation
   *
   * @param userAgent user agent
   * @param winningStrategy winning strategy
   */
  public RobotsTxtImpl(MatchingStrategy matchingStrategy, WinningStrategy winningStrategy) {
    this.matchingStrategy = matchingStrategy;
    this.winningStrategy = winningStrategy;
  }

  @Override
  public String getHost() {
    return host;
  }

  /**
   * Sets host.
   *
   * @param host host name
   */
  public void setHost(String host) {
    this.host = host;
  }

  @Override
  public List getSitemaps() {
    return sitemaps;
  }

  /**
   * Sets crawl delay.
   *
   * @param crawlDelay crawl delay.
   */
  public void setCrawlDelay(Integer crawlDelay) {
    this.crawlDelay = crawlDelay;
  }

  @Override
  public Integer getCrawlDelay() {
    return crawlDelay;
  }

  @Override
  public boolean query(String userAgent, String path) {
    List select = select(userAgent, path);
    Access winner = winningStrategy.selectWinner(select);
    return winner!=null? winner.hasAccess(): true;
  }
  
  /**
   * Adds section.
   *
   * @param section section
   */
  public void addGroup(Group section) {
    if (section != null) {
      if (section.isAnyAgent()) {
        if (this.defaultSection == null) {
          this.defaultSection = section;
        } else {
          this.defaultSection.getAccessList().importAccess(section.getAccessList());
        }
      } else {
        Group exact = findExactSection(section);
        if (exact == null) {
          groups.add(section);
        } else {
          exact.getAccessList().importAccess(section.getAccessList());
        }
      }
    }
  }

  @Override
  public String toString() {
    StringWriter sw = new StringWriter();
    PrintWriter pw = new PrintWriter(sw);
    
    if (defaultSection!=null) {
      pw.println(defaultSection);
    }
    
    groups.forEach(group->{ pw.println(group); /*w.println();*/ });
    
    if (crawlDelay != null && crawlDelay > 0) {
      pw.format("Crawl-delay: %d", crawlDelay).println();
    }
    
    if (host != null) {
      pw.format("Host: %s", host).println();
    }
    
    sitemaps.forEach(sitemap->pw.format("Sitemap: %s", sitemap).println());
    
    pw.flush();
    
    return sw.toString();
  }

  /**
   * Finds exact section.
   *
   * @param section section to find exact
   * @return exact section or {@code null} if no exact section found
   */
  private Group findExactSection(Group section) {
    for (Group s : groups) {
      if (s.isExact(section)) {
        return s;
      }
    }
    return null;
  }

  private List select(String userAgent, String path) {
    String relativePath = assureRelative(path);

    if (relativePath != null && !"/robots.txt".equalsIgnoreCase(relativePath)) {
      ArrayList selected = new ArrayList<>();

      Group sec = findSectionByAgent(groups, userAgent);
      if (sec != null) {
        selected.addAll(sec.select(userAgent, relativePath, matchingStrategy));
      } else if (defaultSection != null) {
        selected.addAll(defaultSection.select(userAgent, relativePath, matchingStrategy));
      }
      return selected;
    } else {
      return Collections.EMPTY_LIST;
    }
  }

  private Group findSectionByAgent(List sections, String userAgent) {
    for (Group sec : sections) {
      if (sec.matchUserAgent(userAgent)) {
        return sec;
      }
    }
    return null;
  }

  private String assureRelative(String path) {
    try {
      URI uri = new URI(path);
      if (uri.isAbsolute()) {
        URL url = uri.toURL();
        path = String.format("/%s%s%s", url.getPath(), url.getQuery() != null ? "#" + url.getQuery() : "", url.getRef() != null ? "#" + url.getRef() : "").replaceAll("/+", "/");
      }
      return path;
    } catch (Exception ex) {
      return path;
    }
  }
}