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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head><meta http-equiv="content-type" content="text/html; charset=UTF-8" /><title>FetchDNS xref</title><link type="text/css" rel="stylesheet" href="../../../../stylesheet.css" /></head><body><div id="overview"><a href="../../../../../apidocs/org/archive/crawler/fetcher/FetchDNS.html">View Javadoc</a></div><pre><a name="1" href="#1">1</a> <em class="comment">/*<em class="comment"> Copyright (C) 2003 Internet Archive.</em></em><a name="2" href="#2">2</a> <em class="comment"> *</em><a name="3" href="#3">3</a> <em class="comment"> * This file is part of the Heritrix web crawler (crawler.archive.org).</em><a name="4" href="#4">4</a> <em class="comment"> *</em><a name="5" href="#5">5</a> <em class="comment"> * Heritrix is free software; you can redistribute it and/or modify</em><a name="6" href="#6">6</a> <em class="comment"> * it under the terms of the GNU Lesser Public License as published by</em><a name="7" href="#7">7</a> <em class="comment"> * the Free Software Foundation; either version 2.1 of the License, or</em><a name="8" href="#8">8</a> <em class="comment"> * any later version.</em><a name="9" href="#9">9</a> <em class="comment"> *</em><a name="10" href="#10">10</a> <em class="comment"> * Heritrix is distributed in the hope that it will be useful,</em><a name="11" href="#11">11</a> <em class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</em><a name="12" href="#12">12</a> <em class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</em><a name="13" href="#13">13</a> <em class="comment"> * GNU Lesser Public License for more details.</em><a name="14" href="#14">14</a> <em class="comment"> *</em><a name="15" href="#15">15</a> <em class="comment"> * You should have received a copy of the GNU Lesser Public License</em><a name="16" href="#16">16</a> <em class="comment"> * along with Heritrix; if not, write to the Free Software</em><a name="17" href="#17">17</a> <em class="comment"> * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</em><a name="18" href="#18">18</a> <em class="comment"> *</em><a name="19" href="#19">19</a> <em class="comment"> * FetchDNS</em><a name="20" href="#20">20</a> <em class="comment"> * Created on Jun 5, 2003</em><a name="21" href="#21">21</a> <em class="comment"> *</em><a name="22" href="#22">22</a> <em class="comment"> * $Header: /cvsroot/archive-crawler/ArchiveOpenCrawler/src/java/org/archive/crawler/fetcher/FetchDNS.java,v 1.29 2006/08/01 23:07:37 stack-sf Exp $</em><a name="23" href="#23">23</a> <em class="comment"> */</em><a name="24" href="#24">24</a> <strong>package</strong> <a href="../../../../org/archive/crawler/fetcher/package-summary.html">org.archive.crawler.fetcher</a>;<a name="25" href="#25">25</a> <a name="26" href="#26">26</a> <strong>import</strong> java.io.ByteArrayInputStream;<a name="27" href="#27">27</a> <strong>import</strong> java.io.ByteArrayOutputStream;<a name="28" href="#28">28</a> <strong>import</strong> java.io.IOException;<a name="29" href="#29">29</a> <strong>import</strong> java.io.InputStream;<a name="30" href="#30">30</a> <strong>import</strong> java.net.InetAddress;<a name="31" href="#31">31</a> <strong>import</strong> java.net.UnknownHostException;<a name="32" href="#32">32</a> <strong>import</strong> java.util.logging.Level;<a name="33" href="#33">33</a> <strong>import</strong> java.util.logging.Logger;<a name="34" href="#34">34</a> <strong>import</strong> java.util.regex.Matcher;<a name="35" href="#35">35</a> <a name="36" href="#36">36</a> <strong>import</strong> org.apache.commons.httpclient.URIException;<a name="37" href="#37">37</a> <strong>import</strong> org.archive.crawler.datamodel.CoreAttributeConstants;<a name="38" href="#38">38</a> <strong>import</strong> org.archive.crawler.datamodel.CrawlHost;<a name="39" href="#39">39</a> <strong>import</strong> org.archive.crawler.datamodel.CrawlURI;<a name="40" href="#40">40</a> <strong>import</strong> org.archive.crawler.datamodel.FetchStatusCodes;<a name="41" href="#41">41</a> <strong>import</strong> org.archive.crawler.framework.Processor;<a name="42" href="#42">42</a> <strong>import</strong> org.archive.crawler.settings.SimpleType;<a name="43" href="#43">43</a> <strong>import</strong> org.archive.util.ArchiveUtils;<a name="44" href="#44">44</a> <strong>import</strong> org.archive.util.HttpRecorder;<a name="45" href="#45">45</a> <strong>import</strong> org.archive.util.InetAddressUtil;<a name="46" href="#46">46</a> <strong>import</strong> org.xbill.DNS.ARecord;<a name="47" href="#47">47</a> <strong>import</strong> org.xbill.DNS.DClass;<a name="48" href="#48">48</a> <strong>import</strong> org.xbill.DNS.FindServer;<a name="49" href="#49">49</a> <strong>import</strong> org.xbill.DNS.Record;<a name="50" href="#50">50</a> <strong>import</strong> org.xbill.DNS.Type;<a name="51" href="#51">51</a> <strong>import</strong> org.xbill.DNS.dns;<a name="52" href="#52">52</a> <a name="53" href="#53">53</a> <a name="54" href="#54">54</a> <em>/**<em>*</em></em><a name="55" href="#55">55</a> <em> * Processor to resolve 'dns:' URIs.</em><a name="56" href="#56">56</a> <em> * </em><a name="57" href="#57">57</a> <em> * TODO: Refactor to use org.archive.util.DNSJavaUtils.</em><a name="58" href="#58">58</a> <em> *</em><a name="59" href="#59">59</a> <em> * @author multiple</em><a name="60" href="#60">60</a> <em> */</em><a name="61" href="#61">61</a> <strong>public</strong> <strong>class</strong> <a href="../../../../org/archive/crawler/fetcher/FetchDNS.html">FetchDNS</a> <strong>extends</strong> <a href="../../../../org/archive/crawler/framework/Processor.html">Processor</a><a name="62" href="#62">62</a> implements CoreAttributeConstants, <a href="../../../../org/archive/crawler/datamodel/FetchStatusCodes.html">FetchStatusCodes</a> {<a name="63" href="#63">63</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> <strong>long</strong> serialVersionUID = 4686199203459704426L;<a name="64" href="#64">64</a> <a name="65" href="#65">65</a> <strong>private</strong> Logger logger = Logger.getLogger(<strong>this</strong>.getClass().getName());<a name="66" href="#66">66</a> <a name="67" href="#67">67</a> <em class="comment">// Defaults.</em><a name="68" href="#68">68</a> <strong>private</strong> <strong>short</strong> ClassType = DClass.IN;<a name="69" href="#69">69</a> <strong>private</strong> <strong>short</strong> TypeType = Type.A;<a name="70" href="#70">70</a> <strong>protected</strong> InetAddress serverInetAddr = <strong>null</strong>;<a name="71" href="#71">71</a> <a name="72" href="#72">72</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> String ATTR_ACCEPT_NON_DNS_RESOLVES =<a name="73" href="#73">73</a> <span class="string">"accept-non-dns-resolves"</span>;<a name="74" href="#74">74</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> Boolean DEFAULT_ACCEPT_NON_DNS_RESOLVES =<a name="75" href="#75">75</a> Boolean.FALSE;<a name="76" href="#76">76</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> <strong>long</strong> DEFAULT_TTL_FOR_NON_DNS_RESOLVES<a name="77" href="#77">77</a> = 6 * 60 * 60; <em class="comment">// 6 hrs</em><a name="78" href="#78">78</a> <a name="79" href="#79">79</a> <strong>private</strong> byte [] reusableBuffer = <strong>new</strong> byte[1024];<a name="80" href="#80">80</a> <a name="81" href="#81">81</a> <em>/**<em>* </em></em><a name="82" href="#82">82</a> <em> * Create a new instance of FetchDNS.</em><a name="83" href="#83">83</a> <em> *</em><a name="84" href="#84">84</a> <em> * @param name the name of this attribute.</em><a name="85" href="#85">85</a> <em> */</em><a name="86" href="#86">86</a> <strong>public</strong> <a href="../../../../org/archive/crawler/fetcher/FetchDNS.html">FetchDNS</a>(String name) {<a name="87" href="#87">87</a> <strong>super</strong>(name, <span class="string">"DNS Fetcher. Handles DNS lookups."</span>);<a name="88" href="#88">88</a> org.archive.crawler.settings.Type e =<a name="89" href="#89">89</a> addElementToDefinition(<strong>new</strong> <a href="../../../../org/archive/crawler/settings/SimpleType.html">SimpleType</a>(ATTR_ACCEPT_NON_DNS_RESOLVES,<a name="90" href="#90">90</a> <span class="string">"If a DNS lookup fails, whether or not to fallback to "</span> +<a name="91" href="#91">91</a> <span class="string">"InetAddress resolution, which may use local 'hosts' files "</span> +<a name="92" href="#92">92</a> <span class="string">"or other mechanisms."</span>, DEFAULT_ACCEPT_NON_DNS_RESOLVES));<a name="93" href="#93">93</a> e.setExpertSetting(<strong>true</strong>);<a name="94" href="#94">94</a> e = addElementToDefinition(<strong>new</strong> <a href="../../../../org/archive/crawler/settings/SimpleType.html">SimpleType</a>(FetchHTTP.ATTR_SHA1_CONTENT,<a name="95" href="#95">95</a> <span class="string">"Whether or not to perform an on-the-fly SHA1 hash of"</span> +<a name="96" href="#96">96</a> <span class="string">"retrieved content-bodies."</span>,<a name="97" href="#97">97</a> FetchHTTP.DEFAULT_SHA1_CONTENT));<a name="98" href="#98">98</a> e.setExpertSetting(<strong>true</strong>);<a name="99" href="#99">99</a> }<a name="100" href="#100">100</a> <a name="101" href="#101">101</a> <strong>protected</strong> <strong>void</strong> innerProcess(<a href="../../../../org/archive/crawler/datamodel/CrawlURI.html">CrawlURI</a> curi) {<a name="102" href="#102">102</a> <strong>if</strong> (!curi.getUURI().getScheme().equals(<span class="string">"dns"</span>)) {<a name="103" href="#103">103</a> <em class="comment">// Only handles dns</em><a name="104" href="#104">104</a> <strong>return</strong>;<a name="105" href="#105">105</a> }<a name="106" href="#106">106</a> Record[] rrecordSet = <strong>null</strong>; <em class="comment">// Retrieved dns records</em><a name="107" href="#107">107</a> String dnsName = <strong>null</strong>;<a name="108" href="#108">108</a> <strong>try</strong> {<a name="109" href="#109">109</a> dnsName = curi.getUURI().getReferencedHost();<a name="110" href="#110">110</a> } <strong>catch</strong> (URIException e) {<a name="111" href="#111">111</a> logger.log(Level.SEVERE, <span class="string">"Failed parse of dns record "</span> + curi, e);<a name="112" href="#112">112</a> }<a name="113" href="#113">113</a> <a name="114" href="#114">114</a> <strong>if</strong>(dnsName == <strong>null</strong>) {<a name="115" href="#115">115</a> curi.setFetchStatus(S_UNFETCHABLE_URI);<a name="116" href="#116">116</a> <strong>return</strong>;<a name="117" href="#117">117</a> }<a name="118" href="#118">118</a> <a name="119" href="#119">119</a> <em class="comment">// Make sure we're in "normal operating mode", e.g. a cache +</em><a name="120" href="#120">120</a> <em class="comment">// controller exist to assist us.</em><a name="121" href="#121">121</a> <a href="../../../../org/archive/crawler/datamodel/CrawlHost.html">CrawlHost</a> targetHost = <strong>null</strong>;<a name="122" href="#122">122</a> <strong>if</strong> (getController() != <strong>null</strong> &&<a name="123" href="#123">123</a> getController().getServerCache() != <strong>null</strong>) {<a name="124" href="#124">124</a> targetHost = getController().getServerCache().getHostFor(dnsName);<a name="125" href="#125">125</a> } <strong>else</strong> {<a name="126" href="#126">126</a> <em class="comment">// Standalone operation (mostly for test cases/potential other uses)</em><a name="127" href="#127">127</a> targetHost = <strong>new</strong> <a href="../../../../org/archive/crawler/datamodel/CrawlHost.html">CrawlHost</a>(dnsName);<a name="128" href="#128">128</a> }<a name="129" href="#129">129</a> <strong>if</strong> (isQuadAddress(curi, dnsName, targetHost)) {<a name="130" href="#130">130</a> <em class="comment">// We're done processing.</em><a name="131" href="#131">131</a> <strong>return</strong>;<a name="132" href="#132">132</a> }<a name="133" href="#133">133</a> <a name="134" href="#134">134</a> <em class="comment">// Do actual DNS lookup.</em><a name="135" href="#135">135</a> curi.putLong(A_FETCH_BEGAN_TIME, System.currentTimeMillis());<a name="136" href="#136">136</a> <a name="137" href="#137">137</a> <em class="comment">// Try to get the records for this host (assume domain name)</em><a name="138" href="#138">138</a> <em class="comment">// TODO: Bug #935119 concerns potential hang here</em><a name="139" href="#139">139</a> rrecordSet = dns.getRecords(dnsName, TypeType, ClassType);<a name="140" href="#140">140</a> curi.setContentType(<span class="string">"text/dns"</span>);<a name="141" href="#141">141</a> <strong>if</strong> (rrecordSet != <strong>null</strong>) {<a name="142" href="#142">142</a> <strong>if</strong> (logger.isLoggable(Level.FINE)) {<a name="143" href="#143">143</a> logger.fine(<span class="string">"Found recordset for "</span> + dnsName);<a name="144" href="#144">144</a> }<a name="145" href="#145">145</a> storeDNSRecord(curi, dnsName, targetHost, rrecordSet);<a name="146" href="#146">146</a> } <strong>else</strong> {<a name="147" href="#147">147</a> <strong>if</strong> (logger.isLoggable(Level.FINE)) {<a name="148" href="#148">148</a> logger.fine(<span class="string">"Failed find of recordset for "</span> + dnsName);<a name="149" href="#149">149</a> }<a name="150" href="#150">150</a> <strong>if</strong> (((Boolean)getUncheckedAttribute(<strong>null</strong>,<a name="151" href="#151">151</a> ATTR_ACCEPT_NON_DNS_RESOLVES)).booleanValue()) {<a name="152" href="#152">152</a> <em class="comment">// Do lookup that bypasses javadns.</em><a name="153" href="#153">153</a> InetAddress address = <strong>null</strong>;<a name="154" href="#154">154</a> <strong>try</strong> {⌨️ 快捷键说明
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