// plasmaHTCache.java
// -----------------------
// part of YaCy
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// 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.
/*
Class documentation:
This class has two purposes:
1. provide a object that carries path and header information
that shall be used as objects within a scheduler's stack
2. static methods for a cache control and cache aging
the class shall also be used to do a cache-cleaning and index creation
*/
package de.anomic.plasma;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashSet;
import java.io.IOException;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import de.anomic.htmlFilter.htmlFilterContentScraper;
import de.anomic.http.httpHeader;
import de.anomic.http.httpc;
import de.anomic.kelondro.kelondroDyn;
import de.anomic.kelondro.kelondroMScoreCluster;
import de.anomic.kelondro.kelondroMap;
import de.anomic.server.serverFileUtils;
import de.anomic.server.serverInstantThread;
import de.anomic.server.logging.serverLog;
import de.anomic.server.serverDate;
import de.anomic.tools.enumerateFiles;
public final class plasmaHTCache {
private static final int stackLimit = 150; // if we exceed that limit, we do not check idle
public static final long oneday = 1000 * 60 * 60 * 24; // milliseconds of a day
private kelondroMap responseHeaderDB = null;
private final LinkedList cacheStack;
private final TreeMap cacheAge; // a <date+hash, cache-path> - relation
public long currCacheSize;
public long maxCacheSize;
public final File cachePath;
public final serverLog log;
public static final HashSet filesInUse = new HashSet(); // can we delete this file
public plasmaHTCache(File htCachePath, long maxCacheSize, int bufferkb) {
// this.switchboard = switchboard;
this.log = new serverLog("HTCACHE");
this.cachePath = htCachePath;
this.maxCacheSize = maxCacheSize;
// reset old HTCache ?
final String[] list = cachePath.list();
if (list != null) {
File object;
for (int i = list.length - 1; i >= 0 ; i--) {
object = new File(cachePath, list[i]);
if (object.isDirectory()) {
if (!object.getName().equals("http") &&
!object.getName().equals("yacy") &&
!object.getName().equals("https") &&
!object.getName().equals("ftp") &&
!object.getName().equals("anon")) {
deleteOldHTCache(cachePath);
break;
}
}
}
}
// set/make cache path
if (!htCachePath.exists()) {
htCachePath.mkdirs();
}
if (!htCachePath.isDirectory()) {
// if the cache does not exists or is a file and not a directory, panic
this.log.logSevere("the cache path " + htCachePath.toString() + " is not a directory or does not exists and cannot be created");
System.exit(0);
}
// open the response header database
File dbfile = new File(this.cachePath, "responseHeader.db");
try {
if (dbfile.exists())
this.responseHeaderDB = new kelondroMap(new kelondroDyn(dbfile, bufferkb * 0x400, '#'));
else
this.responseHeaderDB = new kelondroMap(new kelondroDyn(dbfile, bufferkb * 0x400, plasmaURL.urlHashLength, 150, '#', false));
} catch (IOException e) {
this.log.logSevere("the request header database could not be opened: " + e.getMessage());
System.exit(0);
}
// init stack
this.cacheStack = new LinkedList();
// init cache age and size management
this.cacheAge = new TreeMap();
this.currCacheSize = 0;
this.maxCacheSize = maxCacheSize;
// start the cache startup thread
// this will collect information about the current cache size and elements
serverInstantThread.oneTimeJob(this, "cacheScan", this.log, 120000);
}
private void deleteOldHTCache(File directory) {
String[] list = directory.list();
if (list != null) {
File object;
for (int i = list.length - 1; i >= 0 ; i--) {
object = new File(directory, list[i]);
if (object.isFile()) {
object.delete();
} else {
deleteOldHTCache(object);
}
}
}
directory.delete();
}
public int size() {
synchronized (this.cacheStack) {
return this.cacheStack.size();
}
}
public int dbSize() {
return this.responseHeaderDB.size();
}
public int[] dbCacheChunkSize() {
return this.responseHeaderDB.cacheChunkSize();
}
public int[] dbCacheFillStatus() {
return this.responseHeaderDB.cacheFillStatus();
}
public void push(Entry entry) {
synchronized (this.cacheStack) {
this.cacheStack.add(entry);
}
}
public Entry pop() {
synchronized (this.cacheStack) {
if (this.cacheStack.size() > 0)
return (Entry) this.cacheStack.removeFirst();
return null;
}
}
public void storeHeader(String urlHash, httpHeader responseHeader) throws IOException {
this.responseHeaderDB.set(urlHash, responseHeader);
}
/**
* This method changes the HTCache size.<br>
* @param new cache size in bytes
*/
public final void setCacheSize(long newCacheSize) {
this.maxCacheSize = newCacheSize;
}
/**
* This method returns the free HTCache size.<br>
* @return the cache size in bytes
*/
public long getFreeSize() {
return (this.currCacheSize >= this.maxCacheSize) ? 0 : this.maxCacheSize - this.currCacheSize;
}
public boolean writeFile(URL url, byte[] array) {
if (array == null) return false;
File file = getCachePath(url);
try {
deleteFile(file);
file.getParentFile().mkdirs();
serverFileUtils.write(array, file);
} catch (FileNotFoundException e) {
// this is the case of a "(Not a directory)" error, which should be prohibited
// by the shallStoreCache() property. However, sometimes the error still occurs
// In this case do nothing.
this.log.logSevere("File storage failed (not a directory): " + e.getMessage());
return false;
} catch (IOException e) {
this.log.logSevere("File storage failed (IO error): " + e.getMessage());
return false;
}
writeFileAnnouncement(file);
return true;
}
public void writeFileAnnouncement(File file) {
synchronized (this.cacheAge) {
if (file.exists()) {
this.currCacheSize += file.length();
this.cacheAge.put(ageString(file.lastModified(), file), file);
cleanup();
}
}
}
public boolean deleteFile(URL url) {
return deleteURLfromCache(url, "FROM");
}
private boolean deleteURLfromCache (URL url, String msg) {
if (deleteFileandDirs(getCachePath(url), msg)) {
try {
// As the file is gone, the entry in responseHeader.db is not needed anymore
this.log.logFinest("Trying to remove responseHeader from URL: " + url.toString());
this.responseHeaderDB.remove(plasmaURL.urlHash(url));
} catch (IOException e) {
this.log.logInfo("IOExeption removing response header from DB: " + e.getMessage(), e);
}
return true;
}
return false;
}
private boolean deleteFile(File obj) {
if (obj.exists() && !filesInUse.contains(obj)) {
long size = obj.length();
if (obj.delete()) {
this.currCacheSize -= size;
return true;
}
}
return false;
}
private boolean deleteFileandDirs (File obj, String msg) {
if (deleteFile(obj)) {
this.log.logInfo("DELETED " + msg + " CACHE : " + obj.toString());
obj = obj.getParentFile();
// If the has been emptied, remove it
// Loop as long as we produce empty driectoriers, but stop at HTCACHE
while ((!(obj.equals(this.cachePath))) && (obj.isDirectory()) && (obj.list().length == 0)) {
if (obj.delete()) this.log.logFine("DELETED EMPTY DIRECTORY : " + obj.toString());
obj = obj.getParentFile();
}
return true;
}
return false;
}
private void cleanupDoIt(long newCacheSize) {
File obj;
Iterator iter = this.cacheAge.keySet().iterator();
while (iter.hasNext() && this.currCacheSize >= newCacheSize) {
Object key = iter.next();
obj = (File) this.cacheAge.get(key);
if (obj != null) {
if (filesInUse.contains(obj)) continue;
this.log.logFinest("Trying to delete old file: " + obj.toString());
if (deleteFileandDirs (obj, "OLD")) {
try {
// As the file is gone, the entry in responseHeader.db is not needed anymore
this.log.logFinest("Trying to remove responseHeader for URL: " +
getURL(this.cachePath ,obj).toString());
this.responseHeaderDB.remove(plasmaURL.urlHash(getURL(this.cachePath ,obj)));
} catch (IOException e) {
this.log.logInfo("IOExeption removing response header from DB: " +
e.getMessage(), e);
}
}
}
iter.remove();
}
}
private void cleanup() {
// clean up cache to have 4% (enough) space for next entries
if (this.cacheAge.size() > 0 && this.currCacheSize >= this.maxCacheSize) {
if (this.maxCacheSize > 0) { cleanupDoIt(this.maxCacheSize - (this.maxCacheSize / 100) * 4); }
}
}
public void close() {
try {this.responseHeaderDB.close();} catch (IOException e) {}
}
private String ageString(long date, File f) {
StringBuffer sb = new StringBuffer(32);
String s = Long.toHexString(date);
for (int i = s.length(); i < 16; i++) sb.append('0');
sb.append(s);
s = Integer.toHexString(f.hashCode());
for (int i = s.length(); i < 8; i++) sb.append('0');
sb.append(s);
return sb.toString();
}
public void cacheScan() {
log.logConfig("STARTING HTCACHE SCANNING");
kelondroMScoreCluster doms = new kelondroMScoreCluster();
int c = 0;
enumerateFiles ef = new enumerateFiles(this.cachePath, true, false, true, true);
File f;
while (ef.hasMoreElements()) {
c++;
f = (File) ef.nextElement();
long d = f.lastModified();
//System.out.println("Cache: " + dom(f));
doms.incScore(dom(f));
this.currCacheSize += f.length();
this.cacheAge.put(ageString(d, f), f);
try {Thread.sleep(10);} catch (InterruptedException e) {}
}
//System.out.println("%" + (String) cacheAge.firstKey() + "=" + cacheAge.get(cacheAge.firstKey()));
long ageHours = 0;
try {
ageHours = (System.currentTimeMillis() -
Long.parseLong(((String) this.cacheAge.firstKey()).substring(0, 16), 16)) / 3600000;
} catch (NumberFormatException e) {
//e.printStackTrace();
}
this.log.logConfig("CACHE SCANNED, CONTAINS " + c +
" FILES = " + this.currCacheSize/1048576 + "MB, OLDEST IS " +
((ageHours < 24) ? (ageHours + " HOURS") : ((ageHours / 24) + " DAYS")) + " OLD");
cleanup();
log.logConfig("STARTING DNS PREFETCH");
// start to prefetch IPs from DNS
String dom;
long start = System.currentTimeMillis();
String result = "";
c = 0;
while ((doms.size() > 0) && (c < 50) && ((System.currentTimeMillis() - start) < 60000)) {
dom = (String) doms.getMaxObject();
InetAddress ip = httpc.dnsResolve(dom);
if (ip == null) continue;
result += ", " + dom + "=" + ip.getHostAddress();
this.log.logConfig("PRE-FILLED " + dom + "=" + ip.getHostAddress());
c++;
doms.deleteScore(dom);
// wait a short while to prevent that this looks like a DoS
try {Thread.sleep(100);} catch (InterruptedException e) {}
}
if (result.length() > 2) this.log.logConfig("PRE-FILLED DNS CACHE, FETCHED " + c +
" ADDRESSES: " + result.substring(2));
}
private String dom(File f) {
String s = f.toString().substring(this.cachePath.toString().length() + 1);
int p = s.indexOf("/");
if (p < 0) p = s.indexOf("\\");
if (p < 0) return null;
return s.substring(0, p);
}
public httpHeader getCachedResponse(String urlHash) throws IOException {
Map hdb = this.responseHeaderDB.get(urlHash);
if (hdb == null) return null;
return new httpHeader(null, hdb);
}
public boolean full() {
return (this.cacheStack.size() > stackLimit);
}
public boolean empty() {
return (this.cacheStack.size() == 0);
}
public static boolean isPicture(httpHeader response) {
Object ct = response.get(httpHeader.CONTENT_TYPE);
if (ct == null) return false;
return ((String)ct).toUpperCase().startsWith("IMAGE");
}
public static boolean isText(httpHeader response) {
// Object ct = response.get(httpHeader.CONTENT_TYPE);
// if (ct == null) return false;
// String t = ((String)ct).toLowerCase();
// return ((t.startsWith("text")) || (t.equals("application/xhtml+xml")));
return plasmaParser.supportedMimeTypesContains(response.mime());
}
public static boolean noIndexingURL(String urlString) {
if (urlString == null) return false;
urlString = urlString.toLowerCase();
// return (
// (urlString.endsWith(".gz")) ||
// (urlString.endsWith(".msi")) ||
// (urlString.endsWith(".doc")) ||
// (urlString.endsWith(".zip")) ||
// (urlString.endsWith(".tgz")) ||
// (urlString.endsWith(".rar")) ||
// (urlString.endsWith(".pdf")) ||
// (urlString.endsWith(".ppt")) ||
// (urlString.endsWith(".xls")) ||
// (urlString.endsWith(".log")) ||
// (urlString.endsWith(".java")) ||
// (urlString.endsWith(".c")) ||
// (urlString.endsWith(".p"))
// );
int idx = urlString.indexOf("?");
if (idx > 0) urlString = urlString.substring(0,idx);
idx = urlString.lastIndexOf(".");
if (idx > 0) urlString = urlString.substring(idx+1);
return plasmaParser.mediaExtContains(urlString);
}
/* public File getCachePath(URL url) {
// this.log.logFinest("plasmaHTCache: getCachePath: IN=" + url.toString());
String remotePath = url.getFile();
if (!remotePath.startsWith("/")) { remotePath = "/" + remotePath; }
if (remotePath.endsWith("/")) { remotePath = remotePath + "ndx"; }
remotePath = remotePath.replaceAll("[?&:]", "_"); // yes this is not reversible, but that is not needed
int port = url.getPort();
if (port < 0) {
if (url.getProtocol().equalsIgnoreCase("http")) port = 80;
else if (url.getProtocol().equalsIgnoreCase("https")) port = 443;
else if (url.getProtocol().equalsIgnoreCase("ftp")) port = 21;
}
if (port == 80) {
return new File(this.cachePath, url.getHost() + remotePath);
} else {
return new File(this.cachePath, url.getHost() + "!" + port + remotePath);
}
} */
/* public static URL getURL(File cachePath, File f) {
// this.log.logFinest("plasmaHTCache: getURL: IN: Path=[" + cachePath + "]");
// this.log.logFinest("plasmaHTCache: getURL: IN: File=[" + f + "]");
String s = f.toString().replace('\\', '/');
final String c = cachePath.toString().replace('\\', '/');
String protocol = "http://";
int pos = s.lastIndexOf(c);
if (pos >= 0) {
s = s.substring(pos + c.length());
while (s.startsWith("/")) s = s.substring(1);
pos = s.indexOf("!");
if (pos >= 0) {
String temp = s.substring(pos + 1);
if (temp.startsWith("443/")) {
protocol = "https://";
} else if (temp.startsWith("21/")) {
protocol = "ftp://";
}
s = s.substring(0, pos) + ":" + s.substring(pos + 1);
}
if (s.endsWith("ndx")) { s = s.substring(0, s.length() - 3); }
// this.log.logFinest("plasmaHTCache: getURL: OUT=" + s);
try {
return new URL(protocol + s);
} catch (Exception e) {
return null;
}
}
return null;
}*/
/**
* this method creates from a given host and path a cache path
* from a given host (which may also be an IPv4 - number, but not IPv6 or
* a domain; all without leading 'http://') and a path (which must start
* with a leading '/', and may also end in an '/') a path to a file
* in the file system with root as given in cachePath is constructed
* it will also be ensured, that the complete path exists; if necessary
* that path will be generated
* @return new File
*/
public File getCachePath(URL url) {
// this.log.logFinest("plasmaHTCache: getCachePath: IN=" + url.toString());
String path = url.getPath();
String query = url.getQuery();
if (!path.startsWith("/")) { path = "/" + path; }
if (path.endsWith("/") && query == null) { path = path + "ndx"; }
Pattern searchPattern = Pattern.compile("/\\.\\./");
Matcher matcher = searchPattern.matcher(path);
while (matcher.find()) {
path = matcher.replaceAll("/!!/");
matcher.reset(path);
}
if (query != null) {
// yes this is not reversible, but that is not needed
searchPattern = Pattern.compile("(\"|\\\\|\\*|\\?|/|:|<|>|\\|)");
matcher = searchPattern.matcher(query);
while (matcher.find()) {
query = matcher.replaceAll("_");
matcher.reset(query);
}
path = path.concat("_").concat(query);
}
// only set NO default ports
int port = url.getPort();
String protocol = url.getProtocol();
if (port >= 0) {
if ((port == 80 && protocol.equalsIgnoreCase("http" )) ||
(port == 443 && protocol.equalsIgnoreCase("https")) ||
(port == 21 && protocol.equalsIgnoreCase("ftp" ))) {
port = -1;
}
}
if (url.getHost().toLowerCase().endsWith(".yacy")) {
protocol = "yacy";
}
if (port < 0) {
return new File(this.cachePath, protocol + "/" + url.getHost() + path);
} else {
return new File(this.cachePath, protocol + "/" + url.getHost() + "!" + port + path);
}
/* File path;
if (port < 0) {
path = new File(this.cachePath, url.getHost() + remotePath);
} else {
path = new File(this.cachePath, url.getHost() + "!" + port + remotePath);
}
this.log.logFinest("plasmaHTCache: getCachePath: OUT=" + path.toString());
return path; */
}
/**
* this is the reverse function to getCachePath: it constructs the url as string
* from a given storage path
*/
public static URL getURL(File cachePath, File f) {
// this.log.logFinest("plasmaHTCache: getURL: IN: Path=[" + cachePath + "] File=[" + f + "]");
final String c = cachePath.toString().replace('\\', '/');
String s = f.toString().replace('\\', '/');
if (s.endsWith("ndx")) { s = s.substring(0, s.length() - 3); }
int pos = s.lastIndexOf(c);
if (pos == 0) {
s = s.substring(pos + c.length());
while (s.startsWith("/")) { s = s.substring(1); }
String protocol = "";
if (s.startsWith("http/")) {
protocol = "http://";
s = s.substring(5);
} else if (s.startsWith("https/")) {
protocol = "https://";
s = s.substring(6);
} else if (s.startsWith("ftp/")) {
protocol = "ftp://";
s = s.substring(4);
} else if (s.startsWith("yacy/")) {
protocol = "http://";
s = s.substring(5);
} else {
return null;
}
Pattern pathPattern = Pattern.compile("/!!/");
Matcher matcher = pathPattern.matcher(s);
while (matcher.find()) {
s = matcher.replaceAll("/\\.\\./");
matcher.reset(s);
}
pos = s.indexOf("!");
if (pos >= 0) {
s = s.substring(0, pos) + ":" + s.substring(pos + 1);
}
// this.log.logFinest("plasmaHTCache: getURL: OUT=" + s);
try {
return new URL(protocol + s);
} catch (Exception e) {
return null;
}
}
return null;
}
public byte[] loadResource(URL url) {
// load the url as resource from the cache
File f = getCachePath(url);
if (f.exists()) try {
return serverFileUtils.read(f);
} catch (IOException e) {
return null;
}
return null;
}
public static boolean isPOST(String urlString) {
return (urlString.indexOf("?") >= 0 ||
urlString.indexOf("&") >= 0);
}
public static boolean isCGI(String urlString) {
String ls = urlString.toLowerCase();
return ((ls.indexOf(".cgi") >= 0) ||
(ls.indexOf(".exe") >= 0) ||
(ls.indexOf(";jsessionid=") >= 0) ||
(ls.indexOf("sessionid/") >= 0) ||
(ls.indexOf("phpsessid=") >= 0) ||
(ls.indexOf("search.php?sid=") >= 0) ||
(ls.indexOf("memberlist.php?sid=") >= 0));
}
public Entry newEntry(Date initDate, int depth, URL url, String name,
httpHeader requestHeader,
String responseStatus, httpHeader responseHeader,
String initiator,
plasmaCrawlProfile.entry profile) {
return new Entry(initDate, depth, url, name, requestHeader, responseStatus, responseHeader, initiator, profile);
}
public final class Entry {
// the class objects
public Date initDate; // the date when the request happened; will be used as a key
public int depth; // the depth of prefetching
public httpHeader requestHeader; // we carry also the header to prevent too many file system access
public String responseStatus;
public httpHeader responseHeader; // we carry also the header to prevent too many file system access
public File cacheFile; // the cache file
public byte[] cacheArray; // or the cache as byte-array
public URL url;
public String name; // the name of the link, read as anchor from an <a>-tag
public String nomalizedURLHash;
public String nomalizedURLString;
public int status; // cache load/hit/stale etc status
public Date lastModified;
public char doctype;
public String language;
public plasmaCrawlProfile.entry profile;
private String initiator;
protected Object clone() throws CloneNotSupportedException {
return new Entry(
this.initDate,
this.depth,
this.url,
this.name,
this.requestHeader,
this.responseStatus,
this.responseHeader,
this.initiator,
this.profile
);
}
public Entry(Date initDate, int depth, URL url, String name,
httpHeader requestHeader,
String responseStatus, httpHeader responseHeader,
String initiator,
plasmaCrawlProfile.entry profile) {
// normalize url
// serverLog.logFine("PLASMA", "Entry: URL=" + url.toString());
this.nomalizedURLString = htmlFilterContentScraper.urlNormalform(url);
try {
this.url = new URL(this.nomalizedURLString);
} catch (MalformedURLException e) {
System.out.println("internal error at httpdProxyCache.Entry: " + e);
System.exit(-1);
}
this.name = name;
this.cacheFile = getCachePath(this.url);
this.nomalizedURLHash = plasmaURL.urlHash(this.nomalizedURLString);
// assigned:
this.initDate = initDate;
this.depth = depth;
this.requestHeader = requestHeader;
this.responseStatus = responseStatus;
this.responseHeader = responseHeader;
this.profile = profile;
this.initiator = (initiator == null) ? null : ((initiator.length() == 0) ? null: initiator);
// calculated:
if (responseHeader == null) {
try {
throw new RuntimeException("RESPONSE HEADER = NULL");
} catch (Exception e) {
System.out.println("RESPONSE HEADER = NULL in " + url);
e.printStackTrace();
System.exit(0);
}
this.lastModified = new Date(serverDate.correctedUTCTime());
} else {
this.lastModified = responseHeader.lastModified();
if (this.lastModified == null) this.lastModified = new Date(serverDate.correctedUTCTime()); // does not exist in header
}
this.doctype = plasmaWordIndexEntry.docType(responseHeader.mime());
if (this.doctype == plasmaWordIndexEntry.DT_UNKNOWN) this.doctype = plasmaWordIndexEntry.docType(url);
this.language = plasmaWordIndexEntry.language(url);
// to be defined later:
this.cacheArray = null;
}
public String name() {
return this.name;
}
public String initiator() {
return this.initiator;
}
public boolean proxy() {
return initiator() == null;
}
public long size() {
if (this.cacheArray == null) return 0;
return this.cacheArray.length;
}
public URL referrerURL() {
if (this.requestHeader == null) return null;
try {
return new URL((String) this.requestHeader.get(httpHeader.REFERER, ""));
} catch (Exception e) {
return null;
}
}
/*
public boolean update() {
return ((status == CACHE_FILL) || (status == CACHE_STALE_RELOAD_GOOD));
}
*/
// the following three methods for cache read/write granting shall be as loose as possible
// but also as strict as necessary to enable caching of most items
public String shallStoreCacheForProxy() {
// returns NULL if the answer is TRUE
// in case of FALSE, the reason as String is returned
// check profile
if (!this.profile.storeHTCache()) { return "storage_not_wanted"; }
// decide upon header information if a specific file should be stored to the cache or not
// if the storage was requested by prefetching, the request map is null
// check status code
if (!(this.responseStatus.startsWith("200") ||
this.responseStatus.startsWith("203"))) { return "bad_status_" + this.responseStatus.substring(0,3); }
// check storage location
// sometimes a file name is equal to a path name in the same directory;
// or sometimes a file name is equal a directory name created earlier;
// we cannot match that here in the cache file path and therefore omit writing into the cache
if (this.cacheFile.getParentFile().isFile() || this.cacheFile.isDirectory()) { return "path_ambiguous"; }
if (this.cacheFile.toString().indexOf("..") >= 0) { return "path_dangerous"; }
if (this.cacheFile.getAbsolutePath().length() > 250) { return "path too long"; }
// -CGI access in request
// CGI access makes the page very individual, and therefore not usable in caches
if (isPOST(this.nomalizedURLString) && !this.profile.crawlingQ()) { return "dynamic_post"; }
if (isCGI(this.nomalizedURLString)) { return "dynamic_cgi"; }
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"; }
}
// -ranges in request and response
// we do not cache partial content
if (this.responseHeader != null && 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;
}
/**
* decide upon header information if a specific file should be taken from the cache or not
* @return
*/
public boolean shallUseCacheForProxy() {
// System.out.println("SHALL READ CACHE: requestHeader = " + requestHeader.toString() + ", responseHeader = " + responseHeader.toString());
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; }
}
}
// -CGI access in request
// CGI access makes the page very individual, and therefore not usable in caches
if (isPOST(this.nomalizedURLString)) { return false; }
if (isCGI(this.nomalizedURLString)) { 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; }
}
if (!isPicture(this.responseHeader)) {
// -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;
}
} // class Entry
/*
public static void main(String[] args) {
//String[] s = TimeZone.getAvailableIDs();
//for (int i = 0; i < s.length; i++) System.out.println("ZONE=" + s[i]);
Calendar c = GregorianCalendar.getInstance();
int zoneOffset = c.get(Calendar.ZONE_OFFSET)/(60*60*1000);
int DSTOffset = c.get(Calendar.DST_OFFSET)/(60*60*1000);
System.out.println("This Offset = " + (zoneOffset + DSTOffset));
for (int i = 0; i < 12; i++) {
c = new GregorianCalendar(TimeZone.getTimeZone("Etc/GMT-" + i));
//c.setTimeZone(TimeZone.getTimeZone("Etc/GMT+0"));
System.out.println("Zone offset: "+
c.get(Calendar.ZONE_OFFSET)/(60*60*1000));
System.out.println(c.get(GregorianCalendar.HOUR) + ", " + c.getTime() + ", " + c.getTimeInMillis());
}
}
**/
}