| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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 org.apache.nutch.urlfilter.prefix; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.hadoop.conf.Configuration; |
| |
| import org.apache.nutch.util.PrefixStringMatcher; |
| import org.apache.nutch.util.TrieStringMatcher; |
| import org.apache.nutch.net.URLFilter; |
| import org.apache.nutch.plugin.Extension; |
| import org.apache.nutch.plugin.PluginRepository; |
| |
| import java.lang.invoke.MethodHandles; |
| import java.io.Reader; |
| import java.io.BufferedReader; |
| import java.io.InputStreamReader; |
| import java.io.IOException; |
| import java.io.StringReader; |
| |
| import java.util.List; |
| import java.util.ArrayList; |
| |
| /** |
| * Filters URLs based on a file of URL prefixes. The file is named by (1) |
| * property "urlfilter.prefix.file" in ./conf/nutch-default.xml, or (2) |
| * the attribute "file" in plugin.xml of this plugin. |
| * |
| * <p> |
| * The format of this file is one URL prefix per line. |
| * </p> |
| */ |
| public class PrefixURLFilter implements URLFilter { |
| |
| private static final Logger LOG = LoggerFactory |
| .getLogger(MethodHandles.lookup().lookupClass()); |
| |
| // read in attribute "file" of this plugin. |
| private static String attributeFile = null; |
| |
| private TrieStringMatcher trie; |
| |
| private Configuration conf; |
| |
| public PrefixURLFilter() throws IOException { |
| |
| } |
| |
| public PrefixURLFilter(String stringRules) throws IOException { |
| trie = readConfiguration(new StringReader(stringRules)); |
| } |
| |
| public String filter(String url) { |
| if (trie.shortestMatch(url) == null) |
| return null; |
| else |
| return url; |
| } |
| |
| private TrieStringMatcher readConfiguration(Reader reader) throws IOException { |
| |
| BufferedReader in = new BufferedReader(reader); |
| List<String> urlprefixes = new ArrayList<>(); |
| String line; |
| |
| while ((line = in.readLine()) != null) { |
| if (line.length() == 0) |
| continue; |
| |
| char first = line.charAt(0); |
| switch (first) { |
| case ' ': |
| case '\n': |
| case '#': // skip blank & comment lines |
| continue; |
| default: |
| urlprefixes.add(line); |
| } |
| } |
| |
| return new PrefixStringMatcher(urlprefixes); |
| } |
| |
| public static void main(String args[]) throws IOException { |
| |
| PrefixURLFilter filter; |
| if (args.length >= 1) |
| filter = new PrefixURLFilter(args[0]); |
| else |
| filter = new PrefixURLFilter(); |
| |
| BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); |
| String line; |
| while ((line = in.readLine()) != null) { |
| String out = filter.filter(line); |
| if (out != null) { |
| System.out.println(out); |
| } |
| } |
| } |
| |
| public void setConf(Configuration conf) { |
| this.conf = conf; |
| |
| String pluginName = "urlfilter-prefix"; |
| Extension[] extensions = PluginRepository.get(conf) |
| .getExtensionPoint(URLFilter.class.getName()).getExtensions(); |
| for (int i = 0; i < extensions.length; i++) { |
| Extension extension = extensions[i]; |
| if (extension.getDescriptor().getPluginId().equals(pluginName)) { |
| attributeFile = extension.getAttribute("file"); |
| break; |
| } |
| } |
| |
| if (attributeFile != null && attributeFile.trim().isEmpty()) { |
| attributeFile = null; |
| } |
| |
| if (attributeFile != null) { |
| LOG.info("Attribute \"file\" is defined for plugin {} as {}", pluginName, attributeFile); |
| } |
| |
| // precedence hierarchy for definition of filter rules |
| // (first non-empty definition takes precedence): |
| // 1. string rules defined by `urlfilter.domaindenylist.rules` |
| // 2. rule file name defined by `urlfilter.domaindenylist.file` |
| // 3. rule file name defined in plugin.xml (`attributeFile`) |
| String file = conf.get("urlfilter.prefix.file", attributeFile); |
| String stringRules = conf.get("urlfilter.prefix.rules"); |
| Reader reader = null; |
| if (stringRules != null) { // takes precedence over files |
| reader = new StringReader(stringRules); |
| } else { |
| LOG.info("Reading {} rules file {}", pluginName, file); |
| reader = conf.getConfResourceAsReader(file); |
| } |
| |
| if (reader == null) { |
| LOG.warn("Missing {} rule file '{}': all URLs will be rejected!", |
| pluginName, file); |
| trie = new PrefixStringMatcher(new String[0]); |
| } else { |
| try { |
| trie = readConfiguration(reader); |
| } catch (IOException e) { |
| LOG.error("Error reading " + pluginName + " rule file " + file, e); |
| } |
| } |
| } |
| |
| public Configuration getConf() { |
| return this.conf; |
| } |
| |
| } |