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yacy_search_server/source/net/yacy/kelondro/data/meta/DigestURI.java

361 lines
13 KiB

// DigestURI.java
// (C) 2006 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 13.07.2006 on http://yacy.net
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// LICENSE
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package net.yacy.kelondro.data.meta;
// this class exist to provide a system-wide normal form representation of urls,
// and to prevent that java.net.URL usage causes DNS queries which are used in java.net.
import java.io.File;
import java.io.Serializable;
import java.net.MalformedURLException;
import net.yacy.cora.document.ASCII;
import net.yacy.cora.document.MultiProtocolURI;
import net.yacy.cora.protocol.Domains;
import net.yacy.kelondro.logging.Log;
import net.yacy.kelondro.order.Base64Order;
import net.yacy.kelondro.order.Digest;
import net.yacy.kelondro.util.ByteArray;
/**
* URI-object providing YaCy-hash computation
*
* Hashes for URIs are split in several parts
* For URIs pointing to resources not globally available,
* the domainhash-part gets one reserved value
*/
public class DigestURI extends MultiProtocolURI implements Serializable {
private static final long serialVersionUID = -1173233022912141885L;
public static final int TLD_any_zone_filter = 255; // from TLD zones can be filtered during search; this is the catch-all filter
// class variables
private byte[] hash;
/**
* Shortcut, calculate hash for shorted url/hostname
* @param host
* @return
*/
public static String hosthash(final String host) {
String h = host;
if (!h.startsWith("http://")) h = "http://" + h;
DigestURI url = null;
try {
url = new DigestURI(h);
} catch (final MalformedURLException e) {
Log.logException(e);
return null;
}
return (url == null) ? null : ASCII.String(url.hash(), 6, 6);
}
/**
* DigestURI from File
*/
public DigestURI(final File file) throws MalformedURLException {
this("file", "", -1, file.getAbsolutePath());
}
/**
* DigestURI from URI string
*/
public DigestURI(final String url) throws MalformedURLException {
this(url, null);
}
/**
* DigestURI from URI string, hash is already calculated
* @param url
* @param hash already calculated hash for url
* @throws MalformedURLException
*/
public DigestURI(final String url, final byte[] hash) throws MalformedURLException {
super(url);
this.hash = hash;
}
/**
* DigestURI from general URI
* @param baseURL
*/
public DigestURI(final MultiProtocolURI baseURL) {
super(baseURL);
this.hash = (baseURL instanceof DigestURI) ? ((DigestURI) baseURL).hash : null;
}
/**
* DigestURI from general URI, hash already calculated
* @param baseURL
* @param hash
*/
public DigestURI(final MultiProtocolURI baseURL, final byte[] hash) {
super(baseURL);
this.hash = hash;
}
public DigestURI(final MultiProtocolURI baseURL, final String relPath) throws MalformedURLException {
super(baseURL, relPath);
this.hash = null;
}
public DigestURI(final String protocol, final String host, final int port, final String path) throws MalformedURLException {
super(protocol, host, port, path);
this.hash = null;
}
/* (non-Javadoc)
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
return ByteArray.hashCode(hash());
}
public static final int flagTypeID(final String hash) {
return (Base64Order.enhancedCoder.decodeByte(hash.charAt(11)) & 32) >> 5;
}
public static final int flagTLDID(final String hash) {
return (Base64Order.enhancedCoder.decodeByte(hash.charAt(11)) & 28) >> 2;
}
public static final int flagLengthID(final String hash) {
return (Base64Order.enhancedCoder.decodeByte(hash.charAt(11)) & 3);
}
/**
* get YaCy-hash of URI
* @return
*/
public final byte[] hash() {
// in case that the object was initialized without a known url hash, compute it now
if (this.hash == null) {
// we check the this.hash value twice to avoid synchronization where possible
synchronized (this.protocol) {
if (this.hash == null) this.hash = urlHashComputation();
}
}
return this.hash;
}
/**
* calculated YaCy-Hash of this URI
*
* @note needs DNS lookup to check if the addresses domain is local
* that causes that this method may be very slow
*
* @return hash
*/
private final byte[] urlHashComputation() {
// the url hash computation needs a DNS lookup to check if the addresses domain is local
// that causes that this method may be very slow
assert this.hash == null; // should only be called if the hash was not computed before
final int id = Domains.getDomainID(this.host, this.hostAddress); // id=7: tld is local
final boolean isHTTP = isHTTP();
int p = (this.host == null) ? -1 : this.host.lastIndexOf('.');
String dom = (p > 0) ? dom = this.host.substring(0, p) : "";
p = dom.lastIndexOf('.'); // locate subdomain
String subdom = "";
if (p > 0) {
subdom = dom.substring(0, p);
dom = dom.substring(p + 1);
}
// find rootpath
int rootpathStart = 0;
int rootpathEnd = this.path.length() - 1;
if (this.path.length() > 0 && this.path.charAt(0) == '/')
rootpathStart = 1;
if (this.path.endsWith("/"))
rootpathEnd = this.path.length() - 2;
p = this.path.indexOf('/', rootpathStart);
String rootpath = "";
if (p > 0 && p < rootpathEnd) {
rootpath = this.path.substring(rootpathStart, p);
}
// we collected enough information to compute the fragments that are
// basis for hashes
final int l = dom.length();
final int domlengthKey = (l <= 8) ? 0 : (l <= 12) ? 1 : (l <= 16) ? 2 : 3;
final byte flagbyte = (byte) (((isHTTP) ? 0 : 32) | (id << 2) | domlengthKey);
// combine the attributes
final StringBuilder hashs = new StringBuilder(12);
assert hashs.length() == 0;
// form the 'local' part of the hash
final String normalform = toNormalform(true, true, false, true);
final String b64l = Base64Order.enhancedCoder.encode(Digest.encodeMD5Raw(normalform));
if (b64l.length() < 5) return null;
hashs.append(b64l.substring(0, 5)); // 5 chars
assert hashs.length() == 5;
hashs.append(subdomPortPath(subdom, this.port, rootpath)); // 1 char
assert hashs.length() == 6;
// form the 'global' part of the hash
hashs.append(hosthash5(this.protocol, this.host, this.port)); // 5 chars
assert hashs.length() == 11;
hashs.append(Base64Order.enhancedCoder.encodeByte(flagbyte)); // 1 char
assert hashs.length() == 12;
// return result hash
final byte[] b = ASCII.getBytes(hashs.toString());
assert b.length == 12;
return b;
}
/**
* return true if the protocol of the URL was 'http'
* this is not true if the protocol was 'https'
* @param hash
* @return true for url hashes that point to http services; false otherwise
*/
public static final boolean flag4HTTPset(final byte[] hash) {
assert hash.length == 12;
final byte flagbyte = hash[11];
return (flagbyte & 32) == 1;
}
private static char subdomPortPath(final String subdom, final int port, final String rootpath) {
final StringBuilder sb = new StringBuilder(subdom.length() + rootpath.length() + 8);
sb.append(subdom).append(':').append(Integer.toString(port)).append(':').append(rootpath);
return Base64Order.enhancedCoder.encode(Digest.encodeMD5Raw(sb.toString())).charAt(0);
}
private static final char rootURLFlag0 = subdomPortPath("", 80, "");
private static final char rootURLFlag1 = subdomPortPath("www", 80, "");
public static final boolean probablyRootURL(final String urlHash) {
final char c = urlHash.charAt(5);
return c == rootURLFlag0 || c == rootURLFlag1;
}
public static final boolean probablyRootURL(final byte[] urlHash) {
final char c = (char) urlHash[5];
return c == rootURLFlag0 || c == rootURLFlag1;
}
private static final String hosthash5(final String protocol, final String host, final int port) {
if (host == null) {
return Base64Order.enhancedCoder.encode(Digest.encodeMD5Raw(protocol)).substring(0, 5);
} else {
final StringBuilder sb = new StringBuilder(host.length() + 15);
sb.append(protocol).append(':').append(host).append(':').append(Integer.toString(port));
return Base64Order.enhancedCoder.encode(Digest.encodeMD5Raw(sb.toString())).substring(0, 5);
}
}
/**
* compute a 6-byte hash fragment that can be used to identify the domain of the url
* @param protocol
* @param host
* @param port
* @return 6 bytes base64 encoded String representing the domain of the url
*/
public static final String hosthash6(final String protocol, final String host, final int port) {
final StringBuilder hash = new StringBuilder(12);
final int id = Domains.getDomainID(host, null); // id=7: tld is local
int p = host.lastIndexOf('.');
String dom = (p > 0) ? dom = host.substring(0, p) : "";
p = dom.lastIndexOf('.');
if (p > 0) dom = dom.substring(p + 1);
final int l = dom.length();
final int domlengthKey = (l <= 8) ? 0 : (l <= 12) ? 1 : (l <= 16) ? 2 : 3;
final byte flagbyte = (byte) (((protocol.equals("http")) ? 0 : 32) | (id << 2) | domlengthKey);
hash.append(hosthash5(protocol, host, port)); // 5 chars
hash.append(Base64Order.enhancedCoder.encodeByte(flagbyte)); // 1 char
// return result hash
return hash.toString();
}
public static final String hosthash6(final String host) {
return hosthash6("http", host, 80);
}
//private static String[] testTLDs = new String[] { "com", "net", "org", "uk", "fr", "de", "es", "it" };
public static final int domLengthEstimation(final byte[] urlHashBytes) {
// generates an estimation of the original domain length
assert (urlHashBytes != null);
assert (urlHashBytes.length == 12) : "urlhash = " + ASCII.String(urlHashBytes);
final int flagbyte = Base64Order.enhancedCoder.decodeByte(urlHashBytes[11]);
final int domLengthKey = flagbyte & 3;
switch (domLengthKey) {
case 0:
return 4;
case 1:
return 10;
case 2:
return 14;
case 3:
return 20;
}
return 20;
}
public static int domLengthNormalized(final byte[] urlHashBytes) {
return domLengthEstimation(urlHashBytes) << 8 / 20;
}
public static final int domDomain(final byte[] urlHash) {
// returns the ID of the domain of the domain
assert (urlHash != null);
assert (urlHash.length == 12 || urlHash.length == 6) : "urlhash = " + ASCII.String(urlHash);
return (Base64Order.enhancedCoder.decodeByte(urlHash[(urlHash.length == 12) ? 11 : 5]) & 28) >> 2;
}
public static boolean isDomDomain(final byte[] urlHash, final int id) {
return domDomain(urlHash) == id;
}
/**
* checks for local/global IP range and local IP
*/
@Override
public final boolean isLocal() {
if (this.isFile()) return true;
if (this.hash == null) synchronized (this.protocol) {
// this is synchronized because another thread may also call the same method in between
// that is the reason that this.hash is checked again
if (this.hash == null) this.hash = urlHashComputation();
}
return domDomain(this.hash) == 7;
}
/**
* checks, if hash is in local/global IP range
* @param urlhash
* @return
*/
public static final boolean isLocal(final byte[] urlhash) {
return domDomain(urlhash) == 7;
}
}