// LoaderDispatcher.java
// (C) 2007 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 24.10.2007 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// 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.repository;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.util.Arrays;
import java.util.Date;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;
import net.yacy.cora.document.encoding.ASCII;
import net.yacy.cora.document.encoding.UTF8;
import net.yacy.cora.document.id.AnchorURL;
import net.yacy.cora.document.id.DigestURL;
import net.yacy.cora.federate.solr.FailCategory;
import net.yacy.cora.federate.yacy.CacheStrategy;
import net.yacy.cora.protocol.ClientIdentification;
import net.yacy.cora.protocol.HeaderFramework;
import net.yacy.cora.protocol.RequestHeader;
import net.yacy.cora.protocol.ResponseHeader;
import net.yacy.cora.util.ConcurrentLog;
import net.yacy.crawler.data.Cache;
import net.yacy.crawler.data.CrawlProfile;
import net.yacy.crawler.retrieval.FTPLoader;
import net.yacy.crawler.retrieval.FileLoader;
import net.yacy.crawler.retrieval.HTTPLoader;
import net.yacy.crawler.retrieval.Request;
import net.yacy.crawler.retrieval.Response;
import net.yacy.crawler.retrieval.SMBLoader;
import net.yacy.document.Document;
import net.yacy.document.Parser;
import net.yacy.document.TextParser;
import net.yacy.kelondro.util.FileUtils;
import net.yacy.repository.Blacklist.BlacklistType;
import net.yacy.search.Switchboard;
public final class LoaderDispatcher {
private final static int accessTimeMaxsize = 1000;
private final static ConcurrentLog log = new ConcurrentLog("LOADER");
private static final ConcurrentHashMap<String, Long> accessTime = new ConcurrentHashMap<String, Long>(); // to protect targets from DDoS
private final Switchboard sb;
private final HashSet<String> supportedProtocols;
private final HTTPLoader httpLoader;
private final FTPLoader ftpLoader;
private final SMBLoader smbLoader;
private final FileLoader fileLoader;
private final ConcurrentHashMap<DigestURL, Semaphore> loaderSteering; // a map that delivers a 'finish' semaphore for urls
public LoaderDispatcher(final Switchboard sb) {
this.sb = sb;
this.supportedProtocols = new HashSet<String>(Arrays.asList(new String[]{"http","https","ftp","smb","file"}));
// initiate loader objects
this.httpLoader = new HTTPLoader(sb, LoaderDispatcher.log);
this.ftpLoader = new FTPLoader(sb, LoaderDispatcher.log);
this.smbLoader = new SMBLoader(sb, LoaderDispatcher.log);
this.fileLoader = new FileLoader(sb, LoaderDispatcher.log);
this.loaderSteering = new ConcurrentHashMap<DigestURL, Semaphore>();
}
public boolean isSupportedProtocol(final String protocol) {
if ((protocol == null) || (protocol.isEmpty())) return false;
return this.supportedProtocols.contains(protocol.trim().toLowerCase());
}
@SuppressWarnings("unchecked")
public HashSet<String> getSupportedProtocols() {
return (HashSet<String>) this.supportedProtocols.clone();
}
/**
* generate a request object
* @param url the target url
* @param forText shows that this was a for-text crawling request
* @param global shows that this was a global crawling request
* @return the request object
*/
public Request request(
final DigestURL url,
final boolean forText,
final boolean global
) {
return new Request(
ASCII.getBytes(this.sb.peers.mySeed().hash),
url,
null,
"",
new Date(),
(forText) ?
((global) ?
this.sb.crawler.defaultTextSnippetGlobalProfile.handle() :
this.sb.crawler.defaultTextSnippetLocalProfile.handle())
:
((global) ?
this.sb.crawler.defaultMediaSnippetGlobalProfile.handle() :
this.sb.crawler.defaultMediaSnippetLocalProfile.handle()), // crawl profile
0,
0,
0);
}
public void load(final DigestURL url, final CacheStrategy cacheStratgy, final int maxFileSize, final File targetFile, BlacklistType blacklistType, ClientIdentification.Agent agent) throws IOException {
final byte[] b = load(request(url, false, true), cacheStratgy, maxFileSize, blacklistType, agent).getContent();
if (b == null) throw new IOException("load == null");
final File tmp = new File(targetFile.getAbsolutePath() + ".tmp");
// transaction-safe writing
final File parent = targetFile.getParentFile();
if (!parent.exists()) parent.mkdirs();
FileUtils.copy(b, tmp);
tmp.renameTo(targetFile);
}
public Response load(final Request request, final CacheStrategy cacheStrategy, final BlacklistType blacklistType, ClientIdentification.Agent agent) throws IOException {
return load(request, cacheStrategy, protocolMaxFileSize(request.url()), blacklistType, agent);
}
/**
* loads a resource from cache or web/ftp/smb/file
* on concurrent execution waits max 5 sec for the prev. loader to fill the cache (except for CacheStrategy.NOCACHE)
*
* @param request the request essentials
* @param cacheStrategy strategy according to NOCACHE, IFFRESH, IFEXIST, CACHEONLY
* @param maxFileSize
* @param blacklistType
* @param agent
* @return the loaded entity in a Response object
* @throws IOException
*/
public Response load(final Request request, final CacheStrategy cacheStrategy, final int maxFileSize, final BlacklistType blacklistType, ClientIdentification.Agent agent) throws IOException {
Semaphore check = this.loaderSteering.get(request.url());
if (check != null && cacheStrategy != CacheStrategy.NOCACHE) {
// a loading process is going on for that url
//ConcurrentLog.info("LoaderDispatcher", "waiting for " + request.url().toNormalform(true));
long t = System.currentTimeMillis();
try { check.tryAcquire(5, TimeUnit.SECONDS);} catch (final InterruptedException e) {}
ConcurrentLog.info("LoaderDispatcher", "waited " + (System.currentTimeMillis() - t) + " ms for " + request.url().toNormalform(true));
// now the process may have terminated and we run a normal loading
// which may be successful faster because of a cache hit
}
this.loaderSteering.put(request.url(), new Semaphore(0));
try {
final Response response = loadInternal(request, cacheStrategy, maxFileSize, blacklistType, agent);
// finally block cleans up loaderSteering and semaphore
return response;
} catch (final Throwable e) {
throw new IOException(e);
} finally {
// release the semaphore anyway
check = this.loaderSteering.remove(request.url()); // = next caller goes directly to loadInternal (is ok we just wanted to fill cash)
if (check != null) check.release(1000); // don't block any other
}
}
/**
* load a resource from the web, from ftp, from smb or a file
* @param request the request essentials
* @param cacheStratgy strategy according to NOCACHE, IFFRESH, IFEXIST, CACHEONLY
* @return the loaded entity in a Response object
* @throws IOException
*/
private Response loadInternal(final Request request, CacheStrategy cacheStrategy, final int maxFileSize, final BlacklistType blacklistType, ClientIdentification.Agent agent) throws IOException {
// get the protocol of the next URL
final DigestURL url = request.url();
if (url.isFile() || url.isSMB()) cacheStrategy = CacheStrategy.NOCACHE; // load just from the file system
final String protocol = url.getProtocol();
final String host = url.getHost();
final CrawlProfile crawlProfile = request.profileHandle() == null ? null : this.sb.crawler.get(UTF8.getBytes(request.profileHandle()));
// check if url is in blacklist
if (blacklistType != null && host != null && Switchboard.urlBlacklist.isListed(blacklistType, host.toLowerCase(), url.getFile())) {
this.sb.crawlQueues.errorURL.push(request.url(), request.depth(), crawlProfile, FailCategory.FINAL_LOAD_CONTEXT, "url in blacklist", -1);
throw new IOException("DISPATCHER Rejecting URL '" + request.url().toString() + "'. URL is in blacklist.$");
}
// check if we have the page in the cache
if (cacheStrategy != CacheStrategy.NOCACHE && crawlProfile != null) {
// we have passed a first test if caching is allowed
// now see if there is a cache entry
final ResponseHeader cachedResponse = (url.isLocal()) ? null : Cache.getResponseHeader(url.hash());
if (cachedResponse != null && Cache.hasContent(url.hash())) {
// yes we have the content
// create request header values and a response object because we need that
// in case that we want to return the cached content in the next step
final RequestHeader requestHeader = new RequestHeader();
requestHeader.put(HeaderFramework.USER_AGENT, agent.userAgent);
DigestURL refererURL = null;
if (request.referrerhash() != null) refererURL = this.sb.getURL(request.referrerhash());
if (refererURL != null) requestHeader.put(RequestHeader.REFERER, refererURL.toNormalform(true));
final Response response = new Response(
request,
requestHeader,
cachedResponse,
crawlProfile,
true,
null);
// check which caching strategy shall be used
if (cacheStrategy == CacheStrategy.IFEXIST || cacheStrategy == CacheStrategy.CACHEONLY) {
// well, just take the cache and don't care about freshness of the content
final byte[] content = Cache.getContent(url.hash());
if (content != null) {
LoaderDispatcher.log.info("cache hit/useall for: " + url.toNormalform(true));
response.setContent(content);
return response;
}
}
// now the cacheStrategy must be CACHE_STRATEGY_IFFRESH, that means we should do a proxy freshness test
//assert cacheStrategy == CacheStrategy.IFFRESH : "cacheStrategy = " + cacheStrategy;
if (response.isFreshForProxy()) {
final byte[] content = Cache.getContent(url.hash());
if (content != null) {
LoaderDispatcher.log.info("cache hit/fresh for: " + url.toNormalform(true));
response.setContent(content);
return response;
}
}
LoaderDispatcher.log.info("cache hit/stale for: " + url.toNormalform(true));
} else if (cachedResponse != null) {
LoaderDispatcher.log.warn("HTCACHE contained response header, but not content for url " + url.toNormalform(true));
}
}
// check case where we want results from the cache exclusively, and never from the Internet (offline mode)
if (cacheStrategy == CacheStrategy.CACHEONLY) {
// we had a chance to get the content from the cache .. its over. We don't have it.
throw new IOException("cache only strategy");
}
// now forget about the cache, nothing there. Try to load the content from the Internet
// check access time: this is a double-check (we checked possibly already in the balancer)
// to make sure that we don't DoS the target by mistake
if (!url.isLocal()) {
final Long lastAccess = accessTime.get(host);
long wait = 0;
if (lastAccess != null) wait = Math.max(0, agent.minimumDelta + lastAccess.longValue() - System.currentTimeMillis());
if (wait > 0) {
// force a sleep here. Instead just sleep we clean up the accessTime map
final long untilTime = System.currentTimeMillis() + wait;
cleanupAccessTimeTable(untilTime);
if (System.currentTimeMillis() < untilTime) {
long frcdslp = untilTime - System.currentTimeMillis();
LoaderDispatcher.log.info("Forcing sleep of " + frcdslp + " ms for host " + host);
try {Thread.sleep(frcdslp);} catch (final InterruptedException ee) {}
}
}
}
// now it's for sure that we will access the target. Remember the access time
if (host != null) {
if (accessTime.size() > accessTimeMaxsize) accessTime.clear(); // prevent a memory leak here
accessTime.put(host, System.currentTimeMillis());
}
// load resource from the internet
Response response = null;
if (protocol.equals("http") || protocol.equals("https")) {
response = this.httpLoader.load(request, crawlProfile, maxFileSize, blacklistType, agent);
} else if (protocol.equals("ftp")) {
response = this.ftpLoader.load(request, true);
} else if (protocol.equals("smb")) {
response = this.smbLoader.load(request, true);
} else if (protocol.equals("file")) {
response = this.fileLoader.load(request, true);
} else {
throw new IOException("Unsupported protocol '" + protocol + "' in url " + url);
}
if (response == null) {
throw new IOException("no response (NULL) for url " + url);
}
if (response.getContent() == null) {
throw new IOException("empty response (code " + response.getStatus() + ") for url " + url.toNormalform(true));
}
// we got something. Now check if we want to store that to the cache
// first check looks if we want to store the content to the cache
if (crawlProfile == null || !crawlProfile.storeHTCache()) {
// no caching wanted. Thats ok, do not write any message
return response;
}
// second check tells us if the protocol tells us something about caching
final String storeError = response.shallStoreCacheForCrawler();
if (storeError == null) {
try {
Cache.store(url, response.getResponseHeader(), response.getContent());
} catch (final IOException e) {
LoaderDispatcher.log.warn("cannot write " + response.url() + " to Cache (3): " + e.getMessage(), e);
}
} else {
LoaderDispatcher.log.warn("cannot write " + response.url() + " to Cache (4): " + storeError);
}
return response;
}
private int protocolMaxFileSize(final DigestURL url) {
if (url.isHTTP() || url.isHTTPS())
return this.sb.getConfigInt("crawler.http.maxFileSize", HTTPLoader.DEFAULT_MAXFILESIZE);
if (url.isFTP())
return this.sb.getConfigInt("crawler.ftp.maxFileSize", (int) FTPLoader.DEFAULT_MAXFILESIZE);
if (url.isSMB())
return this.sb.getConfigInt("crawler.smb.maxFileSize", (int) SMBLoader.DEFAULT_MAXFILESIZE);
return Integer.MAX_VALUE;
}
/**
* load the url as byte[] content from the web or the cache
* @param request
* @param cacheStrategy
* @param timeout
* @return the content as {@link byte[]}
* @throws IOException
*/
public byte[] loadContent(final Request request, final CacheStrategy cacheStrategy, BlacklistType blacklistType, final ClientIdentification.Agent agent) throws IOException {
// try to download the resource using the loader
final Response entry = load(request, cacheStrategy, blacklistType, agent);
if (entry == null) return null; // not found in web
// read resource body (if it is there)
return entry.getContent();
}
public Document[] loadDocuments(final Request request, final CacheStrategy cacheStrategy, final int maxFileSize, BlacklistType blacklistType, final ClientIdentification.Agent agent) throws IOException, Parser.Failure {
// load resource
final Response response = load(request, cacheStrategy, maxFileSize, blacklistType, agent);
final DigestURL url = request.url();
if (response == null) throw new IOException("no Response for url " + url);
// if it is still not available, report an error
if (response.getContent() == null || response.getResponseHeader() == null) throw new IOException("no Content available for url " + url);
// parse resource
Document[] documents = response.parse();
String x_robots_tag = response.getResponseHeader().getXRobotsTag();
if (x_robots_tag.indexOf("noindex",0) >= 0) {
for (Document d: documents) d.setIndexingDenied(true);
}
return documents;
}
public Document loadDocument(final DigestURL location, final CacheStrategy cachePolicy, BlacklistType blacklistType, final ClientIdentification.Agent agent) throws IOException {
// load resource
Request request = request(location, true, false);
final Response response = this.load(request, cachePolicy, blacklistType, agent);
final DigestURL url = request.url();
if (response == null) throw new IOException("no Response for url " + url);
// if it is still not available, report an error
if (response.getContent() == null || response.getResponseHeader() == null) throw new IOException("no Content available for url " + url);
// parse resource
try {
Document[] documents = response.parse();
Document merged = Document.mergeDocuments(location, response.getMimeType(), documents);
String x_robots_tag = response.getResponseHeader().getXRobotsTag();
if (x_robots_tag.indexOf("noindex",0) >= 0) merged.setIndexingDenied(true);
return merged;
} catch(final Parser.Failure e) {
throw new IOException(e.getMessage());
}
}
/**
* load all links from a resource
* @param url the url that shall be loaded
* @param cacheStrategy the cache strategy
* @return a map from URLs to the anchor texts of the urls
* @throws IOException
*/
public final Map<AnchorURL, String> loadLinks(final AnchorURL url, final CacheStrategy cacheStrategy, BlacklistType blacklistType, final ClientIdentification.Agent agent) throws IOException {
final Response response = load(request(url, true, false), cacheStrategy, Integer.MAX_VALUE, blacklistType, agent);
if (response == null) throw new IOException("response == null");
final ResponseHeader responseHeader = response.getResponseHeader();
if (response.getContent() == null) throw new IOException("resource == null");
if (responseHeader == null) throw new IOException("responseHeader == null");
Document[] documents = null;
final String supportError = TextParser.supports(url, responseHeader.mime());
if (supportError != null) throw new IOException("no parser support: " + supportError);
try {
documents = TextParser.parseSource(url, responseHeader.mime(), responseHeader.getCharacterEncoding(), response.depth(), response.getContent());
if (documents == null) throw new IOException("document == null");
} catch (final Exception e) {
throw new IOException("parser error: " + e.getMessage());
}
return Document.getHyperlinks(documents, true);
}
public synchronized static void cleanupAccessTimeTable(final long timeout) {
final Iterator<Map.Entry<String, Long>> i = accessTime.entrySet().iterator();
Map.Entry<String, Long> e;
while (i.hasNext()) {
e = i.next();
if (System.currentTimeMillis() > timeout) break;
if (System.currentTimeMillis() - e.getValue().longValue() > 1000) i.remove();
}
}
public void loadIfNotExistBackground(final DigestURL url, final File cache, final int maxFileSize, BlacklistType blacklistType, final ClientIdentification.Agent agent) {
new Loader(url, cache, maxFileSize, CacheStrategy.IFEXIST, blacklistType, agent).start();
}
public void loadIfNotExistBackground(final DigestURL url, final int maxFileSize, BlacklistType blacklistType, final ClientIdentification.Agent agent) {
new Loader(url, null, maxFileSize, CacheStrategy.IFEXIST, blacklistType, agent).start();
}
private class Loader extends Thread {
private final DigestURL url;
private final File cache;
private final int maxFileSize;
private final CacheStrategy cacheStrategy;
private final BlacklistType blacklistType;
private final ClientIdentification.Agent agent;
public Loader(final DigestURL url, final File cache, final int maxFileSize, final CacheStrategy cacheStrategy, BlacklistType blacklistType, final ClientIdentification.Agent agent) {
this.url = url;
this.cache = cache;
this.maxFileSize = maxFileSize;
this.cacheStrategy = cacheStrategy;
this.blacklistType = blacklistType;
this.agent = agent;
}
@Override
public void run() {
if (this.cache != null && this.cache.exists()) return;
try {
// load from the net
final Response response = load(request(this.url, false, true), this.cacheStrategy, this.maxFileSize, this.blacklistType, this.agent);
final byte[] b = response.getContent();
if (this.cache != null) FileUtils.copy(b, this.cache);
} catch (final MalformedURLException e) {} catch (final IOException e) {}
}
}
}