epubextractor.cpp

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/*
    Copyright (C) 2013  Vishesh Handa <me@vhanda.in>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/


#include "epubextractor.h"

#include <epub.h>

#include "nie.h"
#include "nfo.h"
#include "nco.h"

#include <Soprano/Vocabulary/NAO>

#include <KDebug>
#include <QtCore/QDateTime>
#include <QTextDocument>

using namespace Nepomuk2::Vocabulary;
using namespace Soprano::Vocabulary;

namespace Nepomuk2 {

EPubExtractor::EPubExtractor(QObject* parent, const QVariantList& )
    : ExtractorPlugin(parent)
{

}

QStringList EPubExtractor::mimetypes()
{
    QStringList types;
    types << QLatin1String("application/epub+zip");

    return types;
}

namespace {
    QString fetchMetadata(struct epub* e, const epub_metadata& type) {
        int size = 0;

        unsigned char** data = epub_get_metadata(e, type, &size);
        if( data ) {
            QStringList strList;
            for( int i=0; i<size; i++ ) {
                strList << QString::fromUtf8((char*)data[i]);
                free(data[i]);
            }
            free(data);

            return strList.join(";");
        }
        return QString();
    }
}

SimpleResourceGraph EPubExtractor::extract(const QUrl& resUri, const QUrl& fileUrl, const QString& mimeType)
{
    Q_UNUSED( mimeType );

    struct epub* ePubDoc = epub_open( fileUrl.toLocalFile().toUtf8().constData(), 1 );
    if( !ePubDoc ) {
        kError() << "Invalid document";
        return SimpleResourceGraph();
    }

    SimpleResource fileRes(resUri);
    SimpleResourceGraph graph;

    QString value = fetchMetadata(ePubDoc, EPUB_TITLE);
    if( !value.isEmpty() ) {
        fileRes.addProperty( NIE::title(), value );
    }

    value = fetchMetadata(ePubDoc, EPUB_SUBJECT);
    if( !value.isEmpty() ) {
        fileRes.addProperty( NIE::subject(), value );
    }

    value = fetchMetadata(ePubDoc, EPUB_CREATOR);
    if( !value.isEmpty() ) {
        if( value.startsWith(QLatin1String("aut:"), Qt::CaseInsensitive) ) {
            value = value.mid(4).simplified();
        }
        else if( value.startsWith(QLatin1String("author:"), Qt::CaseInsensitive) ) {
            value = value.mid(7).simplified();
        }

        // A lot of authors have their name written in () again. We discard that part
        int index = value.indexOf( '(' );
        if( index )
            value = value.mid( 0, index );

        SimpleResource con;
        con.addType( NCO::Contact() );
        con.addProperty( NCO::fullname(), value );

        fileRes.addProperty( NCO::creator(), con );
        graph << con;
    }

    // The Contributor just seems to be mostly Calibre aka the Generator
    /*
    value = fetchMetadata(ePubDoc, EPUB_CONTRIB);
    if( !value.isEmpty() ) {
        SimpleResource con;
        con.addType( NCO::Contact() );
        con.addProperty( NCO::fullname(), value );

        fileRes.addProperty( NCO::contributor(), con );
        graph << con;
    }*/

    value = fetchMetadata(ePubDoc, EPUB_PUBLISHER);
    if( !value.isEmpty() ) {
        SimpleResource con;
        con.addType( NCO::Contact() );
        con.addProperty( NCO::fullname(), value );

        fileRes.addProperty( NCO::publisher(), con );
        graph << con;
    }

    value = fetchMetadata(ePubDoc, EPUB_DESCRIPTION);
    if( !value.isEmpty() ) {
        // nao:description is used for user visible comments. This field is generally
        // a huge summary of the ebook
        fileRes.addProperty( NIE::comment(), value );
    }

    value = fetchMetadata(ePubDoc, EPUB_DATE);
    if( !value.isEmpty() ) {
        if( value.startsWith("Unspecified:", Qt::CaseInsensitive) ) {
            value = value.mid( QString("Unspecified:").size() ).simplified();
        }
        int ind = value.indexOf("publication:", Qt::CaseInsensitive);
        if( ind != -1) {
            value = value.mid( ind + QString("publication:").size() ).simplified();
        }
        QDateTime dt = ExtractorPlugin::dateTimeFromString(value);
        if( !dt.isNull() )
            fileRes.addProperty( NIE::contentCreated(), dt );
    }

    //
    // Plain Text
    //

    QString plainText;

    struct eiterator* iter = epub_get_iterator(ePubDoc, EITERATOR_SPINE, 0 );
    do {
        char * curr = epub_it_get_curr(iter);
        if (!curr)
            continue;
        QString html = QString::fromUtf8(curr);

        QTextDocument doc;
        doc.setHtml( html );
        plainText.append( doc.toPlainText() + "\n" );

        if( plainText.size() >= maxPlainTextSize() )
            break;

    } while( epub_it_get_next(iter) );

    epub_free_iterator(iter);

    struct titerator* tit;

    tit = epub_get_titerator(ePubDoc, TITERATOR_NAVMAP, 0 );
    if( !tit ) {
        tit = epub_get_titerator(ePubDoc, TITERATOR_GUIDE, 0 );
    }

    if( epub_tit_curr_valid(tit) ) {
        do {
            char *clink = epub_tit_get_curr_link(tit);

            char* data;
            int size = epub_get_data(ePubDoc, clink, &data);
            free(clink);

            // epub_get_data returns -1 on failure
            if( size > 0 && data ) {
                QString html = QString::fromUtf8(data, size);

                QTextDocument doc;
                doc.setHtml( html );
                plainText.append( doc.toPlainText() + "\n" );
                free(data);

                if( plainText.size() >= maxPlainTextSize() )
                    break;
            }
        } while( epub_tit_next(tit) );
    }
    epub_free_titerator(tit);

    if( !plainText.isEmpty() )
        fileRes.addProperty( NIE::plainTextContent(), plainText );

    if( fileRes.isValid() )
        graph << fileRes;
    return graph;
}

}

NEPOMUK_EXPORT_EXTRACTOR( Nepomuk2::EPubExtractor, "nepomukepubextractor" )