Problems with the user agent in Nutch

I original, reproduced please indicate the source (http://blog.csdn.net/panjunbiao/article/details/16960029).

Apache Nutch 1.7 When crawling a website, an error message appears:

2013-11-25 15:23:37,793 info  API. Httprobotrulesparser-couldn ' t get robots.txt for http://www.xxx.com/: Java.io.EOFException 2013-11-25 15:23:37,893 ERROR http. http-failed to get protocol output java.io.EOFException         at Org.apache.nutch . Protocol.http.HttpResponse.readLine (httpresponse.java:427)         at Org.apache.nutch.protocol.http.HttpResponse.parseStatusLine (httpresponse.java:319)          at Org.apache.nutch.protocol.http.httpresponse.<init> (httpresponse.java:154)          at Org.apache.nutch.protocol.http.Http.getResponse (http.java:64)          at Org.apache.nutch.protocol.http.api.HttpBase.getProtocolOutput ( httpbase.java:140)         at org.apache.nutch.fetcher.fetcher$ Fetcherthread.run (fetcher.java:703) 2013-11-25 15:23:37,903 info  fetcher.Fetcher-fetch of http://www.xxxx.com/ failed with:java.io.eofexception

That is, unable to get the robots.txt file, check the HTTP request there is no obvious problem, other sites can be crawled.
Catch the bag with Wireshark found that the crawl site's GET request received no response, suspicion is user-agent problem.
To test with curl, first use the user-agent that contains the Nutch keyword:

jamess-macbook-pro:~ james$ curl-a "friendly crawler/nutch-1.7"-V http://www.****.com/robots.txt * Adding handle:conn: 0x7fe33400fe00 * Adding handle:send:0 * Adding handle:recv:0 * curl_addhandletopipeline:length:1 *-Conn 0 (0x7fe3 3400fe00) send_pipe:1, recv_pipe:0 * About to connect () to www.****.com port (#0) * Trying 42.121.98.156 ... * Connected to Www.****.com (42.121.98.156) port (#0) > Get/robots.txt http/1.1 > user-agent:friendly crawler/ Nutch-1.7 > Host:www.****.com > Accept: */* > * Empty reply from server * Connection #0 to Host www.****.com l EFT Intact Curl: (Reply) Empty from server

Re-use the user-agent that does not contain the Nutch keyword:

jamess-macbook-pro:~ james$ curl-a "Chrome"-v  http://www.****.com/robots.txt * Adding handle:conn:0x7f82f180fe0 0 * Adding handle:send:0 * Adding handle:recv:0 * curl_addhandletopipeline:length:1 *-Conn 0 (0x7f82f180fe00) send _pipe:1, recv_pipe:0 * About to connect () to  www.****.com port (#0) *   Trying 42.121.98.156 ... * Connected to  www. .com  (42.121.98.156) port (#0) > Get/robots.txt http/1.1 > User-agent:chrome > host:  www. . com > Accept: */* > < http/1.1 OK * Server nginx/1.5.6 is not blacklisted < server:nginx/1.5.6 < Date:mon, 08:51:13 GMT < Content-type:text/plain; Charset=utf-8 < content-length:60 < Last-modified:tue, Dec 01:29:47 GMT < connection:keep-alive < E Tag: "50bd520b-3c" < x-ua-compatible:ie=edge,chrome=1 < X-xss-protection:1; Mode=block < Accept-ranges:bytes < user-agent: * Disallow:/robot/trap Disallow:/page/6559999 * Connection #0 to host  www. . Com left Intact

Sure enough, the target site filters out requests for user-agent that contain nutch keywords, but where to modify the contents of this user-agent field. Search Apache contains http.agent.name source code in./plugin/lib-http/src/java/org/apache/nutch/protocol/http/api/httpbase.java:

//inherited Javadoc   public void setconf (Configuration conf) {      this.conf = Co nf       this.proxyhost = Conf.get ("Http.proxy.host");       This.proxyport = Conf.getint ("Http.proxy.port", 8080);       This.useproxy = (proxyhost! = null && proxyhost.length () > 0);       this.timeout = Conf.getint ("Http.timeout", 10000);       this.maxcontent = Conf.getint ("Http.content.limit", 64 * 1024);       this.useragent = getagentstring (Conf.get ("Http.agent.name"), Conf.get (" Http.agent.version "), Conf              . Get (" Http.agent.description "), Conf.get (" Http.agent.url "), Conf.get (" Http.agent.email "));       this.acceptlanguage = Conf.get ("Http.accept.language", acceptlanguage);     &nbSp This.accept = Conf.get ("http.accept", accept);      //backward-compatible default setting       THIS.USEHTTP11 = Conf.getboolean ("Http.usehttp11", false);       this.robots.setConf (conf);       logconf ();  }

It can be found that http.agent.version is set, modified, problem solved.