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yacy_search_server/source/de/anomic/plasma/cache/http/ResourceInfo.java

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// ResourceInfo.java
// -------------------------------------
// part of YACY
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2006
//
// This file ist contributed by Martin Thelian
//
// $LastChangedDate: 2006-02-20 23:57:42 +0100 (Mo, 20 Feb 2006) $
// $LastChangedRevision: 1715 $
// $LastChangedBy: theli $
//
// 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
//
// Using this software in any meaning (reading, learning, copying, compiling,
// running) means that you agree that the Author(s) is (are) not responsible
// for cost, loss of data or any harm that may be caused directly or indirectly
// by usage of this softare or this documentation. The usage of this software
// is on your own risk. The installation and usage (starting/running) of this
// software may allow other people or application to access your computer and
// any attached devices and is highly dependent on the configuration of the
// software which must be done by the user of the software; the author(s) is
// (are) also not responsible for proper configuration and usage of the
// software, even if provoked by documentation provided together with
// the software.
//
// Any changes to this file according to the GPL as documented in the file
// gpl.txt aside this file in the shipment you received can be done to the
// lines that follows this copyright notice here, but changes must not be
// done inside the copyright notive above. A re-distribution must contain
// the intact and unchanged copyright notice.
// Contributions and changes to the program code must be marked as such.
package de.anomic.plasma.cache.http;
import java.util.Date;
import java.util.Map;
import de.anomic.http.httpHeader;
import de.anomic.plasma.plasmaURL;
import de.anomic.net.URL;
import de.anomic.plasma.plasmaHTCache;
import de.anomic.plasma.cache.IResourceInfo;
import de.anomic.plasma.cache.ResourceInfoFactory;
import de.anomic.server.serverDate;
public class ResourceInfo implements IResourceInfo {
private URL url;
private String urlHash;
private httpHeader responseHeader;
private httpHeader requestHeader;
/**
* Constructor used by the {@link ResourceInfoFactory}
* @param objectURL
* @param objectInfo
*/
public ResourceInfo(URL objectURL, Map objectInfo) {
if (objectURL == null) throw new NullPointerException();
if (objectInfo == null) throw new NullPointerException();
// generating the url hash
this.url = objectURL;
this.urlHash = plasmaURL.urlHash(this.url.toNormalform());
// create the http header object
this.responseHeader = new httpHeader(null, objectInfo);
}
public ResourceInfo(URL objectURL, httpHeader requestHeaders, httpHeader responseHeaders) {
if (objectURL == null) throw new NullPointerException();
if (responseHeaders == null) throw new NullPointerException();
// generating the url hash
this.url = objectURL;
this.urlHash = plasmaURL.urlHash(this.url.toNormalform());
this.requestHeader = requestHeaders;
this.responseHeader = responseHeaders;
}
public Map getMap() {
return this.responseHeader;
}
/**
* @see de.anomic.plasma.cache.IResourceInfo#getMimeType()
*/
public String getMimeType() {
if (this.responseHeader == null) return null;
String mimeType = this.responseHeader.mime();
mimeType = mimeType.trim().toLowerCase();
int pos = mimeType.indexOf(';');
return ((pos < 0) ? mimeType : mimeType.substring(0, pos));
}
public String getCharacterEncoding() {
if (this.responseHeader == null) return null;
return this.responseHeader.getCharacterEncoding();
}
/**
* @see de.anomic.plasma.cache.IResourceInfo#getModificationDate()
*/
public Date getModificationDate() {
Date docDate = null;
if (this.responseHeader != null) {
docDate = this.responseHeader.lastModified();
if (docDate == null) docDate = this.responseHeader.date();
}
if (docDate == null) docDate = new Date(serverDate.correctedUTCTime());
return docDate;
}
public URL getRefererUrl() {
if (this.requestHeader == null) return null;
try {
return new URL((String) this.requestHeader.get(httpHeader.REFERER, ""));
} catch (Exception e) {
return null;
}
}
/**
* @see de.anomic.plasma.cache.IResourceInfo#getUrl()
*/
public URL getUrl() {
return this.url;
}
/**
* @see de.anomic.plasma.cache.IResourceInfo#getUrlHash()
*/
public String getUrlHash() {
return this.urlHash;
}
public void setRequestHeader(httpHeader reqestHeader) {
this.requestHeader = reqestHeader;
}
/**
* @see de.anomic.plasma.cache.IResourceInfo#shallIndexCacheForCrawler()
*/
public String shallIndexCacheForCrawler() {
String mimeType = this.getMimeType();
if (plasmaHTCache.isPicture(mimeType)) { return "Media_Content_(Picture)"; }
if (!plasmaHTCache.isText(mimeType)) { return "Media_Content_(not_text)"; }
return null;
}
/**
* @see de.anomic.plasma.cache.IResourceInfo#shallIndexCacheForProxy()
*/
public String shallIndexCacheForProxy() {
// -set-cookie in response
// the set-cookie from the server does not indicate that the content is special
// thus we do not care about it here for indexing
// a picture cannot be indexed
String mimeType = this.getMimeType();
if (plasmaHTCache.isPicture(mimeType)) {
return "Media_Content_(Picture)";
}
if (!plasmaHTCache.isText(mimeType)) {
return "Media_Content_(not_text)";
}
// -if-modified-since in request
// if the page is fresh at the very moment we can index it
Date ifModifiedSince = getModificationDate();
if ((ifModifiedSince != null) && (this.responseHeader.containsKey(httpHeader.LAST_MODIFIED))) {
// parse date
Date d = this.responseHeader.lastModified();
if (d == null) {
d = new Date(serverDate.correctedUTCTime());
}
// finally, we shall treat the cache as stale if the modification time is after the if-.. time
if (d.after(ifModifiedSince)) {
//System.out.println("***not indexed because if-modified-since");
return "Stale_(Last-Modified>Modified-Since)";
}
}
// -pragma in cached response
if (this.responseHeader.containsKey(httpHeader.PRAGMA) &&
((String) this.responseHeader.get(httpHeader.PRAGMA)).toUpperCase().equals("NO-CACHE")) {
return "Denied_(pragma_no_cache)";
}
// see for documentation also:
// http://www.web-caching.com/cacheability.html
// look for freshnes information
// -expires in cached response
// the expires value gives us a very easy hint when the cache is stale
// sometimes, the expires date is set to the past to prevent that a page is cached
// we use that information to see if we should index it
final Date expires = this.responseHeader.expires();
if (expires != null && expires.before(new Date(serverDate.correctedUTCTime()))) {
return "Stale_(Expired)";
}
// -lastModified in cached response
// this information is too weak to use it to prevent indexing
// even if we can apply a TTL heuristic for cache usage
// -cache-control in cached response
// the cache-control has many value options.
String cacheControl = (String) this.responseHeader.get(httpHeader.CACHE_CONTROL);
if (cacheControl != null) {
cacheControl = cacheControl.trim().toUpperCase();
/* we have the following cases for cache-control:
"public" -- can be indexed
"private", "no-cache", "no-store" -- cannot be indexed
"max-age=<delta-seconds>" -- stale/fresh dependent on date
*/
if (cacheControl.startsWith("PRIVATE") ||
cacheControl.startsWith("NO-CACHE") ||
cacheControl.startsWith("NO-STORE")) {
// easy case
return "Stale_(denied_by_cache-control=" + cacheControl + ")";
// } else if (cacheControl.startsWith("PUBLIC")) {
// // ok, do nothing
} else if (cacheControl.startsWith("MAX-AGE=")) {
// we need also the load date
final Date date = this.responseHeader.date();
if (date == null) {
return "Stale_(no_date_given_in_response)";
}
try {
final long ttl = 1000 * Long.parseLong(cacheControl.substring(8)); // milliseconds to live
if (serverDate.correctedUTCTime() - date.getTime() > ttl) {
//System.out.println("***not indexed because cache-control");
return "Stale_(expired_by_cache-control)";
}
} catch (Exception e) {
return "Error_(" + e.getMessage() + ")";
}
}
}
return null;
}
public String shallStoreCacheForProxy() {
if (this.requestHeader != null) {
// -authorization cases in request
// authorization makes pages very individual, and therefore we cannot use the
// content in the cache
if (this.requestHeader.containsKey(httpHeader.AUTHORIZATION)) { return "personalized"; }
// -ranges in request and response
// we do not cache partial content
if (this.requestHeader.containsKey(httpHeader.RANGE)) { return "partial"; }
}
if (this.responseHeader != null) {
// -ranges in request and response
// we do not cache partial content
if (this.responseHeader.containsKey(httpHeader.CONTENT_RANGE)) { return "partial"; }
// -if-modified-since in request
// we do not care about if-modified-since, because this case only occurres if the
// cache file does not exist, and we need as much info as possible for the indexing
// -cookies in request
// we do not care about cookies, because that would prevent loading more pages
// from one domain once a request resulted in a client-side stored cookie
// -set-cookie in response
// we do not care about cookies in responses, because that info comes along
// any/many pages from a server and does not express the validity of the page
// in modes of life-time/expiration or individuality
// -pragma in response
// if we have a pragma non-cache, we don't cache. usually if this is wanted from
// the server, it makes sense
String cacheControl = (String) this.responseHeader.get(httpHeader.PRAGMA);
if (cacheControl != null && cacheControl.trim().toUpperCase().equals("NO-CACHE")) { return "controlled_no_cache"; }
// -expires in response
// we do not care about expires, because at the time this is called the data is
// obvious valid and that header info is used in the indexing later on
// -cache-control in response
// the cache-control has many value options.
cacheControl = (String) this.responseHeader.get(httpHeader.CACHE_CONTROL);
if (cacheControl != null) {
cacheControl = cacheControl.trim().toUpperCase();
if (cacheControl.startsWith("MAX-AGE=")) {
// we need also the load date
Date date = this.responseHeader.date();
if (date == null) return "stale_no_date_given_in_response";
try {
long ttl = 1000 * Long.parseLong(cacheControl.substring(8)); // milliseconds to live
if (serverDate.correctedUTCTime() - date.getTime() > ttl) {
//System.out.println("***not indexed because cache-control");
return "stale_expired";
}
} catch (Exception e) {
return "stale_error_" + e.getMessage() + ")";
}
}
}
}
return null;
}
public boolean shallUseCacheForProxy() {
String cacheControl;
if (this.requestHeader != null) {
// -authorization cases in request
if (this.requestHeader.containsKey(httpHeader.AUTHORIZATION)) { return false; }
// -ranges in request
// we do not cache partial content
if (this.requestHeader.containsKey(httpHeader.RANGE)) { return false; }
// if the client requests a un-cached copy of the resource ...
cacheControl = (String) this.requestHeader.get(httpHeader.PRAGMA);
if (cacheControl != null && cacheControl.trim().toUpperCase().equals("NO-CACHE")) { return false; }
cacheControl = (String) this.requestHeader.get(httpHeader.CACHE_CONTROL);
if (cacheControl != null) {
cacheControl = cacheControl.trim().toUpperCase();
if (cacheControl.startsWith("NO-CACHE") || cacheControl.startsWith("MAX-AGE=0")) { return false; }
}
// -if-modified-since in request
// The entity has to be transferred only if it has
// been modified since the date given by the If-Modified-Since header.
if (this.requestHeader.containsKey(httpHeader.IF_MODIFIED_SINCE)) {
// checking this makes only sense if the cached response contains
// a Last-Modified field. If the field does not exist, we go the safe way
if (!this.responseHeader.containsKey(httpHeader.LAST_MODIFIED)) { return false; }
// parse date
Date d1, d2;
d2 = this.responseHeader.lastModified(); if (d2 == null) { d2 = new Date(serverDate.correctedUTCTime()); }
d1 = this.requestHeader.ifModifiedSince(); if (d1 == null) { d1 = new Date(serverDate.correctedUTCTime()); }
// finally, we shall treat the cache as stale if the modification time is after the if-.. time
if (d2.after(d1)) { return false; }
}
String mimeType = this.getMimeType();
if (!plasmaHTCache.isPicture(mimeType)) {
// -cookies in request
// unfortunately, we should reload in case of a cookie
// but we think that pictures can still be considered as fresh
// -set-cookie in cached response
// this is a similar case as for COOKIE.
if (this.requestHeader.containsKey(httpHeader.COOKIE) ||
this.responseHeader.containsKey(httpHeader.SET_COOKIE) ||
this.responseHeader.containsKey(httpHeader.SET_COOKIE2)) {
return false; // too strong
}
}
}
// -pragma in cached response
// logically, we would not need to care about no-cache pragmas in cached response headers,
// because they cannot exist since they are not written to the cache.
// So this IF should always fail..
cacheControl = (String) this.responseHeader.get(httpHeader.PRAGMA);
if (cacheControl != null && cacheControl.trim().toUpperCase().equals("NO-CACHE")) { return false; }
// see for documentation also:
// http://www.web-caching.com/cacheability.html
// http://vancouver-webpages.com/CacheNow/
// look for freshnes information
// if we don't have any freshnes indication, we treat the file as stale.
// no handle for freshness control:
// -expires in cached response
// the expires value gives us a very easy hint when the cache is stale
Date expires = this.responseHeader.expires();
if (expires != null) {
// System.out.println("EXPIRES-TEST: expires=" + expires + ", NOW=" + serverDate.correctedGMTDate() + ", url=" + url);
if (expires.before(new Date(serverDate.correctedUTCTime()))) { return false; }
}
Date lastModified = this.responseHeader.lastModified();
cacheControl = (String) this.responseHeader.get(httpHeader.CACHE_CONTROL);
if (cacheControl == null && lastModified == null && expires == null) { return false; }
// -lastModified in cached response
// we can apply a TTL (Time To Live) heuristic here. We call the time delta between the last read
// of the file and the last modified date as the age of the file. If we consider the file as
// middel-aged then, the maximum TTL would be cache-creation plus age.
// This would be a TTL factor of 100% we want no more than 10% TTL, so that a 10 month old cache
// file may only be treated as fresh for one more month, not more.
Date date = this.responseHeader.date();
if (lastModified != null) {
if (date == null) { date = new Date(serverDate.correctedUTCTime()); }
long age = date.getTime() - lastModified.getTime();
if (age < 0) { return false; }
// TTL (Time-To-Live) is age/10 = (d2.getTime() - d1.getTime()) / 10
// the actual living-time is serverDate.correctedGMTDate().getTime() - d2.getTime()
// therefore the cache is stale, if serverDate.correctedGMTDate().getTime() - d2.getTime() > age/10
if (serverDate.correctedUTCTime() - date.getTime() > age / 10) { return false; }
}
// -cache-control in cached response
// the cache-control has many value options.
if (cacheControl != null) {
cacheControl = cacheControl.trim().toUpperCase();
if (cacheControl.startsWith("PRIVATE") ||
cacheControl.startsWith("NO-CACHE") ||
cacheControl.startsWith("NO-STORE")) {
// easy case
return false;
// } else if (cacheControl.startsWith("PUBLIC")) {
// // ok, do nothing
} else if (cacheControl.startsWith("MAX-AGE=")) {
// we need also the load date
if (date == null) { return false; }
try {
final long ttl = 1000 * Long.parseLong(cacheControl.substring(8)); // milliseconds to live
if (serverDate.correctedUTCTime() - date.getTime() > ttl) {
return false;
}
} catch (Exception e) {
return false;
}
}
}
return true;
}
public boolean validResponseStatus(String responseStatus) {
return responseStatus.startsWith("200") ||
responseStatus.startsWith("203");
}
public Date ifModifiedSince() {
return (this.requestHeader == null) ? null : this.requestHeader.ifModifiedSince();
}
public boolean requestWithCookie() {
return (this.requestHeader == null) ? false : this.requestHeader.containsKey(httpHeader.COOKIE);
}
public boolean requestProhibitsIndexing() {
return (this.requestHeader == null)
? false
: this.requestHeader.containsKey(httpHeader.X_YACY_INDEX_CONTROL) &&
((String)this.requestHeader.get(httpHeader.X_YACY_INDEX_CONTROL)).toUpperCase().equals("NO-INDEX");
}
public httpHeader getRequestHeader() {
return this.requestHeader;
}
public httpHeader getResponseHeader() {
return this.responseHeader;
}
}