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86 lines
3.1 KiB
86 lines
3.1 KiB
// URLLicense.java
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// (C) 2007 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
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// first published 03.07.2007 on http://yacy.net
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//
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// This is a part of YaCy, a peer-to-peer based web search engine
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//
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// $LastChangedDate$
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// $LastChangedRevision$
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// $LastChangedBy$
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//
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// LICENSE
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package de.anomic.data;
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import java.util.Random;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentLinkedQueue;
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import net.yacy.kelondro.data.meta.DigestURI;
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public class URLLicense {
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// this class defines a license-generation for URLs
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// it is used in case of snippet- and preview-Image-fetching to grant also non-authorized users the usage of a image-fetcher servlet
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private static final int maxQueue = 500;
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private static final long minCheck = 5000;
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private final Random random;
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private final ConcurrentHashMap<String, DigestURI> permissions;
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private final ConcurrentLinkedQueue<String> aging;
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private long lastCheck;
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private final int keylen;
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public URLLicense(final int keylen) {
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this.permissions = new ConcurrentHashMap<String, DigestURI>();
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this.aging = new ConcurrentLinkedQueue<String>();
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this.lastCheck = System.currentTimeMillis();
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this.random = new Random(System.currentTimeMillis());
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this.keylen = keylen;
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}
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public String aquireLicense(final DigestURI url) {
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// generate license key
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StringBuilder stringBuilder = new StringBuilder();
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if (url == null) return stringBuilder.toString();
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while (stringBuilder.length() < keylen) stringBuilder.append(Integer.toHexString(random.nextInt()));
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String license = stringBuilder.substring(0, keylen);
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// store reference to url with license key
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permissions.put(license, url);
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aging.add(license);
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if (System.currentTimeMillis() - this.lastCheck > minCheck) {
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// check aging
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this.lastCheck = System.currentTimeMillis();
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String s;
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while (aging.size() > maxQueue) {
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s = aging.poll();
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if (s != null) permissions.remove(s);
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}
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}
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// return the license key
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return license;
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}
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public DigestURI releaseLicense(final String license) {
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DigestURI url = null;
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url = permissions.remove(license);
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return url;
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}
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}
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