Package org.apache.nutch.util

Class URLUtil

java.lang.Object
org.apache.nutch.util.URLUtil
public class URLUtil extends Object
Utility class for URL analysis

  • Constructor Details

    • URLUtil

      public URLUtil()

  • Method Details

    • resolveURL

      public static URL resolveURL(URL base, String target) throws MalformedURLException
      Resolve relative URL-s and fix a java.net.URL error in handling of URLs with pure query targets.
      Parameters:
      base - base url
      target - target url (may be relative)
      Returns:
      resolved absolute url.
      Throws:
      MalformedURLException - if the input base URL is malformed

    • getDomainName

      public static String getDomainName(URL url)
      Get the domain name of the URL. The domain name of a URL is the substring of the URL's hostname, w/o subdomain names. As an example
      getDomainName(new URL("https://lucene.apache.org/"))
      will return
      apache.org Special cases:
      • if the hostname does not end in a valid domain suffix, the entire hostname is returned.
      • for URLs without a hostname, an empty string is returned.
      Valid domain suffixes are taken from the https://publicsuffix.org/list/public_suffix_list.dat and are compared using crawler-commons' EffectiveTldFinder. Only ICANN domain suffixes are used. Because EffectiveTldFinder loads the public suffix list as file "effective_tld_names.dat" from the Java classpath, it's possible to use the a specific version of the public suffix list (e.g., the most recent one) by placing the public suffix list with the name "effective_tld_names.dat" in Nutch's conf/ folder. The returned domain names are always normalized to lowercase. See EffectiveTldFinder.getAssignedDomain(String, boolean, boolean)
      Parameters:
      url - input URL to extract the domain from
      Returns:
      the domain name string

    • getDomainName

      public static String getDomainName(String url) throws MalformedURLException
      Returns the domain name of the URL. The domain name of a URL is the substring of the URL's hostname, w/o subdomain names. As an example
      getDomainName("https://lucene.apache.org/")
      will return
      apache.org See getDomainName(URL) for more information.
      Parameters:
      url - input URL string to extract the domain from
      Returns:
      the domain name
      Throws:
      MalformedURLException - if the input URL is malformed

    • getTopLevelDomainName

      public static String getTopLevelDomainName(URL url)
      Returns the top-level domain name of the URL. The top-level domain name of a URL is the substring of the URL's hostname, w/o subdomain names. As an example
      getTopLevelDomainName(new URL("https://www.example.co.uk/"))
      will return
      uk In case of internationalized top-level domains, the ASCII representation is returned.
      Parameters:
      url - input URL to extract the top-level domain name from
      Returns:
      the top-level domain name or null if there is none

    • getTopLevelDomainName

      public static String getTopLevelDomainName(String url) throws MalformedURLException
      Returns the top-level domain name of the URL. The top-level domain name of a URL is the substring of the URL's hostname, w/o subdomain names. As an example
      getTopLevelDomainName("https://www.example.co.uk/")
      will return
      uk In case of internationalized top-level domains, the ASCII representation is returned.
      Parameters:
      url - input URL string to extract the top-level domain name from
      Returns:
      the top-level domain name or null if there is none
      Throws:
      MalformedURLException - if the input URL is malformed

    • isSameDomainName

      public static boolean isSameDomainName(URL url1, URL url2)
      Returns whether the given URLs have the same domain name. As an example,
      isSameDomain(new URL("http://lucene.apache.org") , new URL("http://people.apache.org/"))
      will return true.
      Parameters:
      url1 - first URL to compare domain name
      url2 - second URL to compare domain name
      Returns:
      true if the domain names are equal

    • isSameDomainName

      public static boolean isSameDomainName(String url1, String url2) throws MalformedURLException
      Returns whether the given URLs have the same domain name. As an example,
      isSameDomain("http://lucene.apache.org" ,"http://people.apache.org/")
      will return true.
      Parameters:
      url1 - first URL string to compare domain name
      url2 - second URL string to compare domain name
      Returns:
      true if the domain names are equal
      Throws:
      MalformedURLException - if any of the input URLs are malformed

    • getDomainSuffix

      public static String getDomainSuffix(URL url)
      Returns the public suffix corresponding to the last public part of the hostname. In case of internationalized domain suffixes, the ASCII representation is returned. For the URL https://www.taiuru.māori.nz/ the suffix xn--mori-qsa.nz is returned.
      Parameters:
      url - a URL to extract the domain suffix from
      Returns:
      the domain suffix or null if there is none

    • getDomainSuffix

      public static String getDomainSuffix(String url) throws MalformedURLException
      Returns the domain suffix corresponding to the last public part of the hostname. In case of internationalized domain suffixes, the ASCII representation is returned. For the URL https://www.taiuru.māori.nz/ the suffix xn--mori-qsa.nz is returned.
      Parameters:
      url - a URL to extract the domain suffix from
      Returns:
      the domain suffix or null if there is none
      Throws:
      MalformedURLException - if the input URL string is malformed

    • getHostSegments

      public static String[] getHostSegments(URL url)
      Partitions of the hostname of the url by "."
      Parameters:
      url - a URL to extract host segments from
      Returns:
      a string array of host segments

    • getHostSegments

      public static String[] getHostSegments(String url) throws MalformedURLException
      Partitions of the hostname of the url by "."
      Parameters:
      url - a url string to extract host segments from
      Returns:
      a string array of host segments
      Throws:
      MalformedURLException - if the input url string is malformed

    • chooseRepr

      public static String chooseRepr(String src, String dst, boolean temp)
      Given two urls, a src and a destination of a redirect, it returns the representative url.

      This method implements an extended version of the algorithm used by the Yahoo! Slurp crawler described here:
      How does the Yahoo! webcrawler handle redirects?

      • Choose target url if either url is malformed.
      • If different domains the keep the destination whether or not the redirect is temp or perm
      • a.com -> b.com*
      • If the redirect is permanent and the source is root, keep the source.
      • *a.com -> a.com?y=1 || *a.com -> a.com/xyz/index.html
      • If the redirect is permanent and the source is not root and the destination is root, keep the destination
      • a.com/xyz/index.html -> a.com*
      • If the redirect is permanent and neither the source nor the destination is root, then keep the destination
      • a.com/xyz/index.html -> a.com/abc/page.html*
      • If the redirect is temporary and source is root and destination is not root, then keep the source
      • *a.com -> a.com/xyz/index.html
      • If the redirect is temporary and source is not root and destination is root, then keep the destination
      • a.com/xyz/index.html -> a.com*
      • If the redirect is temporary and neither the source or the destination is root, then keep the shortest url. First check for the shortest host, and if both are equal then check by path. Path is first by length then by the number of / path separators.
      • a.com/xyz/index.html -> a.com/abc/page.html*
      • *www.a.com/xyz/index.html -> www.news.a.com/xyz/index.html
      • If the redirect is temporary and both the source and the destination are root, then keep the shortest sub-domain
      • *www.a.com -> www.news.a.com

      While not in this logic there is a further piece of representative url logic that occurs during indexing and after scoring. During creation of the basic fields before indexing, if a url has a representative url stored we check both the url and its representative url (which should never be the same) against their linkrank scores and the highest scoring one is kept as the url and the lower scoring one is held as the orig url inside of the index.
      Parameters:
      src - The source url.
      dst - The destination url.
      temp - Is the redirect a temporary redirect.
      Returns:
      String The representative url.

    • getHost

      public static String getHost(String url)
      Returns the lowercased hostname for the URL or null if the URL is not well-formed.
      Parameters:
      url - The URL to check.
      Returns:
      String the hostname for the URL.

    • getHost

      public static String getHost(URL url)
      Returns the lowercased hostname for the URL.
      Parameters:
      url - The URL to check.
      Returns:
      String the hostname for the URL.

    • getPage

      public static String getPage(String url)
      Returns the page for the url. The page consists of the protocol, host, and path, but does not include the query string. The host is lowercased but the path is not.
      Parameters:
      url - The url to check.
      Returns:
      String The page for the url.

    • getProtocol

      public static String getProtocol(String url)

    • getProtocol

      public static String getProtocol(URL url)

    • isAscii

      public static boolean isAscii(String str)

    • toASCII

      public static String toASCII(String url)
      Convert URL with IDN host/domain name into the ASCII representation.
      Parameters:
      url - URL string to convert
      Returns:
      URL string with ASCII host/domain name or null if conversion fails.

    • toUNICODE

      public static String toUNICODE(String url)
      Convert URL with IDN host/domain name to the Unicode representation.
      Parameters:
      url - URL string to convert
      Returns:
      URL string with Unicode host/domain name or null if conversion fails.

    • convertIDNA2003

      public static String convertIDNA2003(String host, boolean toAscii, boolean strictIDNA2003) throws MalformedURLException
      Convert IDN host to ASCII or Unicode using Java's built-in IDN class. The conversion supports only IDNA2003, it does not support IDNA2008. However, unless the parameter strictIDNA2003 is true, the methods IDN.toASCII(String, int) resp. IDN.toUnicode(String, int) are called passing the flag IDN.ALLOW_UNASSIGNED to avoid that the conversion fails on characters not in the repertoire of Unicode 3.2.
      Parameters:
      host - host name to be converted (lowercase expected)
      toAscii - if true convert to ASCII, otherwise to Unicode
      strictIDNA2003 - if true, do
      Returns:
      converted host name
      Throws:
      MalformedURLException - if the conversion fails

    • convertIDNA2008

      public static String convertIDNA2008(String host, boolean toAscii) throws MalformedURLException
      Convert IDN host to ASCII or Unicode using ICU's IDNA class. The conversion supports IDNA2008 names.
      Parameters:
      host - host name to be converted (lowercase expected)
      toAscii - if true convert to ASCII, otherwise to Unicode
      Returns:
      converted host name
      Throws:
      MalformedURLException - if the conversion fails

    • isHomePageOf

      public static boolean isHomePageOf(URL url, String hostName)
      Test whether a URL is the home page or root page of a host. This is the case if the URL path is / and query, port, fragment, userinfo are empty resp. not given. In other words the URL is: protocol://hostName/
      Parameters:
      url - the URL to test
      hostName - the host name to test the URL on
      Returns:
      true if the URL is the home or root page of the host

    • main

      public static void main(String[] args)
      For testing
      Parameters:
      args - print with no args to get help