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/*
* This file is part of the Heritrix web crawler (crawler.archive.org).
*
* Licensed to the Internet Archive (IA) by one or more individual
* contributors.
*
* The IA licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.archive.io.warc;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Iterator;
import org.archive.io.ArchiveReader;
import org.archive.io.ArchiveReaderFactory;
import org.archive.io.ArchiveRecord;
import org.archive.io.warc.WARCConstants;
import org.archive.util.ArchiveUtils;
import org.archive.util.FileUtils;
import org.archive.util.zip.GZIPMembersInputStream;
import com.google.common.io.CountingInputStream;
/**
* Factory for WARC Readers.
* Figures whether to give out a compressed file Reader or an uncompressed
* Reader.
* @author stack
* @version $Date: 2006-08-23 17:59:04 -0700 (Wed, 23 Aug 2006) $ $Version$
*/
public class WARCReaderFactory extends ArchiveReaderFactory
implements WARCConstants {
private static final WARCReaderFactory factory = new WARCReaderFactory();
/**
* Shutdown any access to default constructor.
* This factory is Singleton.
*/
private WARCReaderFactory() {
super();
}
public static WARCReader get(String arcFileOrUrl)
throws MalformedURLException, IOException {
return (WARCReader)WARCReaderFactory.factory.
getArchiveReader(arcFileOrUrl);
}
public static WARCReader get(final File f) throws IOException {
return (WARCReader)WARCReaderFactory.factory.getArchiveReader(f);
}
/**
* @param f An arcfile to read.
* @param offset Have returned Reader set to start reading at this offset.
* @return A WARCReader.
* @throws IOException
*/
public static WARCReader get(final File f, final long offset)
throws IOException {
return (WARCReader)WARCReaderFactory.factory.
getArchiveReader(f, offset);
}
protected ArchiveReader getArchiveReader(final File f, final long offset)
throws IOException {
boolean compressed = testCompressedWARCFile(f);
if (!compressed) {
if (!FileUtils.isReadableWithExtensionAndMagic(f,
DOT_WARC_FILE_EXTENSION, WARC_MAGIC)) {
throw new IOException(f.getAbsolutePath()
+ " is not a WARC file.");
}
}
return (WARCReader)(compressed?
WARCReaderFactory.factory.new CompressedWARCReader(f, offset):
WARCReaderFactory.factory.new UncompressedWARCReader(f, offset));
}
public static ArchiveReader get(final String s, final InputStream is,
final boolean atFirstRecord)
throws IOException {
return WARCReaderFactory.factory.getArchiveReader(s, is,
atFirstRecord);
}
protected ArchiveReader getArchiveReader(final String f,
final InputStream is, final boolean atFirstRecord)
throws IOException {
// For now, assume stream is compressed. Later add test of input
// stream or handle exception thrown when figure not compressed stream.
return new CompressedWARCReader(f, is, atFirstRecord);
}
public static WARCReader get(final URL arcUrl, final long offset)
throws IOException {
return (WARCReader)WARCReaderFactory.factory.getArchiveReader(arcUrl,
offset);
}
/**
* Get an ARCReader.
* Pulls the ARC local into whereever the System Property
* java.io.tmpdir points. It then hands back an ARCReader that
* points at this local copy. A close on this ARCReader instance will
* remove the local copy.
* @param arcUrl An URL that points at an ARC.
* @return An ARCReader.
* @throws IOException
*/
public static WARCReader get(final URL arcUrl)
throws IOException {
return (WARCReader)WARCReaderFactory.factory.getArchiveReader(arcUrl);
}
/**
* Check file is compressed WARC.
*
* @param f File to test.
*
* @return True if this is compressed WARC (TODO: Just tests if file is
* GZIP'd file (It begins w/ GZIP MAGIC)).
*
* @exception IOException If file does not exist or is not unreadable.
*/
public static boolean testCompressedWARCFile(final File f)
throws IOException {
FileUtils.assertReadable(f);
boolean compressed = false;
final InputStream is = new FileInputStream(f);
try {
compressed = ArchiveUtils.isGzipped(is);
} finally {
is.close();
}
return compressed;
}
/**
* Uncompressed WARC file reader.
* @author stack
*/
public class UncompressedWARCReader extends WARCReader {
/**
* Constructor.
* @param f Uncompressed arcfile to read.
* @throws IOException
*/
public UncompressedWARCReader(final File f)
throws IOException {
this(f, 0);
}
/**
* Constructor.
*
* @param f Uncompressed file to read.
* @param offset Offset at which to position Reader.
* @throws IOException
*/
public UncompressedWARCReader(final File f, final long offset)
throws IOException {
// File has been tested for existence by time it has come to here.
setIn(new CountingInputStream(getInputStream(f, offset)));
getIn().skip(offset);
initialize(f.getAbsolutePath());
}
/**
* Constructor.
*
* @param f Uncompressed file to read.
* @param is InputStream.
*/
public UncompressedWARCReader(final String f, final InputStream is) {
// Arc file has been tested for existence by time it has come
// to here.
setIn(new CountingInputStream(is));
initialize(f);
}
}
/**
* Compressed WARC file reader.
*
* @author stack
*/
public class CompressedWARCReader extends WARCReader {
/**
* Constructor.
*
* @param f Compressed file to read.
* @throws IOException
*/
public CompressedWARCReader(final File f) throws IOException {
this(f, 0);
}
/**
* Constructor.
*
* @param f Compressed arcfile to read.
* @param offset Position at where to start reading file.
* @throws IOException
*/
public CompressedWARCReader(final File f, final long offset)
throws IOException {
// File has been tested for existence by time it has come to here.
setIn(new GZIPMembersInputStream(getInputStream(f, offset)));
((GZIPMembersInputStream)getIn()).compressedSeek(offset);
setCompressed((offset == 0)); // TODO: does this make sense?!?!
initialize(f.getAbsolutePath());
}
/**
* Constructor.
*
* @param f Compressed arcfile.
* @param is InputStream to use.
* @param atFirstRecord
* @throws IOException
*/
public CompressedWARCReader(final String f, final InputStream is,
final boolean atFirstRecord)
throws IOException {
// Arc file has been tested for existence by time it has come
// to here.
setIn(new GZIPMembersInputStream(is));
setCompressed(true);
initialize(f);
// TODO: Ignore atFirstRecord. Probably doesn't apply in WARC world.
}
/**
* Get record at passed offset.
*
* @param offset Byte index into file at which a record starts.
* @return A WARCRecord reference.
* @throws IOException
*/
public WARCRecord get(long offset) throws IOException {
cleanupCurrentRecord();
((GZIPMembersInputStream)getIn()).compressedSeek(offset);
return (WARCRecord) createArchiveRecord(getIn(), offset);
}
public Iterator iterator() {
/**
* Override ArchiveRecordIterator so can base returned iterator on
* GzippedInputStream iterator.
*/
return new ArchiveRecordIterator() {
private GZIPMembersInputStream gis =
(GZIPMembersInputStream)getIn();
private Iterator gzipIterator = this.gis.memberIterator();
protected boolean innerHasNext() {
return this.gzipIterator.hasNext();
}
protected ArchiveRecord innerNext() throws IOException {
// Get the position before gzipIterator.next moves
// it on past the gzip header.
InputStream is = (InputStream) this.gzipIterator.next();
return createArchiveRecord(is, Math.max(gis.getCurrentMemberStart(), gis.getCurrentMemberEnd()));
}
};
}
protected void gotoEOR(ArchiveRecord rec) throws IOException {
long skipped = 0;
while (getIn().read()>-1) {
skipped++;
}
if(skipped>4) {
System.err.println("unexpected extra data after record "+rec);
}
return;
}
}
public static boolean isWARCSuffix(final String f) {
return (f == null)?
false:
(f.toLowerCase().endsWith(DOT_COMPRESSED_WARC_FILE_EXTENSION))?
true:
(f.toLowerCase().endsWith(DOT_WARC_FILE_EXTENSION))?
true: false;
}
}
