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This project contains some of the configurable modules used within the Heritrix application to crawl the web. The modules in this project can be used in applications other than Heritrix, however.
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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.modules.extractor;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.logging.Logger;

import org.apache.commons.httpclient.URIException;
import org.archive.io.SinkHandlerLogThread;
import org.archive.modules.CrawlURI;
import org.archive.net.UURI;
import org.archive.net.UURIFactory;
import org.archive.util.FileUtils;

/** Allows the caller to process a CrawlURI representing a PDF
 *  for the purpose of extracting URIs
 *
 * @author Parker Thompson
 *
 */
public class ExtractorPDF extends ContentExtractor {

    @SuppressWarnings("unused")
    private static final long serialVersionUID = 3L;

    private static final Logger LOGGER =
        Logger.getLogger(ExtractorPDF.class.getName());

    /**
     * The maximum size of PDF files to consider.  PDFs larger than this
     * maximum will not be searched for links.
     */
    {
        setMaxSizeToParse(10*1024*1024L); // 10MB
    }
    public long getMaxSizeToParse() {
        return (Long) kp.get("maxSizeToParse");
    }
    public void setMaxSizeToParse(long threshold) {
        kp.put("maxSizeToParse",threshold);
    }

    public ExtractorPDF() {
    }
    
    @Override
    protected boolean shouldExtract(CrawlURI uri) {
        long max = getMaxSizeToParse();
        if (uri.getRecorder().getRecordedInput().getSize() > max) {
            return false;
        }

        String ct = uri.getContentType();
        return (ct != null) && (ct.startsWith("application/pdf"));
    }
    
    
    protected boolean innerExtract(CrawlURI curi){
        File tempFile;

        int sn;
	Thread thread = Thread.currentThread();
        if (thread instanceof SinkHandlerLogThread) {
            sn = ((SinkHandlerLogThread)thread).getSerialNumber();
        } else {
            sn = System.identityHashCode(thread);
        }
        try {
            tempFile = File.createTempFile("tt" + sn , "tmp.pdf");
        } catch (IOException ioe) {
            throw new RuntimeException(ioe);
        }

        PDFParser parser;
        ArrayList uris;
        try {
            curi.getRecorder().copyContentBodyTo(tempFile);
            parser = new PDFParser(tempFile.getAbsolutePath());
            uris = parser.extractURIs();
        } catch (IOException e) {
            curi.getNonFatalFailures().add(e);
            return false;
        } catch (RuntimeException e) {
            // Truncated/corrupt  PDFs may generate ClassCast exceptions, or
            // other problems
            curi.getNonFatalFailures().add(e);
            return false;
        } finally {
            FileUtils.deleteSoonerOrLater(tempFile);
        }
        
        if (uris == null) {
            return true;
        }

        for (String uri: uris) {
            try {
                UURI src = curi.getUURI();
                UURI dest = UURIFactory.getInstance(uri);
                LinkContext lc = LinkContext.NAVLINK_MISC;
                Hop hop = Hop.NAVLINK;
                addOutlink(curi, dest, lc, hop);
            } catch (URIException e1) {
                // There may not be a controller (e.g. If we're being run
                // by the extractor tool).
                logUriError(e1, curi.getUURI(), uri);
            }
        }
        
        numberOfLinksExtracted.addAndGet(uris.size());

        LOGGER.fine(curi+" has "+uris.size()+" links.");
        // Set flag to indicate that link extraction is completed.
        return true;
    }
}