com.qwazr.library.pdfbox.PdfBoxParser.java Source code

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Here is the source code for com.qwazr.library.pdfbox.PdfBoxParser.java

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/*
 * Copyright 2015-2017 Emmanuel Keller / QWAZR
 * <p>
 * Licensed 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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 com.qwazr.library.pdfbox;

import com.qwazr.extractor.ParserAbstract;
import com.qwazr.extractor.ParserField;
import com.qwazr.extractor.ParserFieldsBuilder;
import com.qwazr.extractor.ParserResultBuilder;
import com.qwazr.utils.StringUtils;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
import org.apache.pdfbox.pdmodel.PDDocumentInformation;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.text.PDFTextStripper;

import javax.ws.rs.core.MultivaluedMap;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.nio.file.Path;

public class PdfBoxParser extends ParserAbstract {

    private static final String[] DEFAULT_MIMETYPES = { "application/pdf" };

    private static final String[] DEFAULT_EXTENSIONS = { "pdf" };

    final private static ParserField AUTHOR = ParserField.newString("author", "The name of the author");

    final private static ParserField SUBJECT = ParserField.newString("subject", "The subject of the document");

    final private static ParserField PRODUCER = ParserField.newString("producer", "The producer of the document");

    final private static ParserField KEYWORDS = ParserField.newString("keywords", "The keywords of the document");

    final private static ParserField CREATION_DATE = ParserField.newDate("creation_date", null);

    final private static ParserField MODIFICATION_DATE = ParserField.newDate("modification_date", null);

    final private static ParserField LANGUAGE = ParserField.newString("language", null);

    final private static ParserField ROTATION = ParserField.newInteger("rotation", null);

    final private static ParserField NUMBER_OF_PAGES = ParserField.newInteger("number_of_pages", null);

    final private static ParserField CHARACTER_COUNT = ParserField.newInteger("character_count", null);

    final private static ParserField[] FIELDS = { TITLE, AUTHOR, SUBJECT, CONTENT, PRODUCER, KEYWORDS,
            CREATION_DATE, MODIFICATION_DATE, LANGUAGE, ROTATION, NUMBER_OF_PAGES, LANG_DETECTION };

    final private static ParserField PASSWORD = ParserField.newString("password", StringUtils.EMPTY);

    final private static ParserField[] PARAMETERS = { PASSWORD };

    private void extractMetaData(final PDDocument pdf, final ParserFieldsBuilder metas) {
        metas.set(MIME_TYPE, DEFAULT_MIMETYPES[0]);
        final PDDocumentInformation info = pdf.getDocumentInformation();
        if (info != null) {
            metas.add(TITLE, info.getTitle());
            metas.add(SUBJECT, info.getSubject());
            metas.add(AUTHOR, info.getAuthor());
            metas.add(PRODUCER, info.getProducer());
            metas.add(KEYWORDS, info.getKeywords());
            metas.add(CREATION_DATE, info.getCreationDate());
            metas.add(MODIFICATION_DATE, info.getModificationDate());
        }
        int pages = pdf.getNumberOfPages();
        metas.add(NUMBER_OF_PAGES, pages);
        PDDocumentCatalog catalog = pdf.getDocumentCatalog();
        if (catalog != null)
            metas.add(LANGUAGE, catalog.getLanguage());
    }

    /**
     * Extract text content using PDFBox
     *
     * @param pdf
     * @param resultBuilder
     * @throws Exception
     */
    private void parseContent(final PDDocument pdf, final ParserResultBuilder resultBuilder) throws Exception {
        try {
            extractMetaData(pdf, resultBuilder.metas());
            Stripper stripper = new Stripper(resultBuilder);
            stripper.getText(pdf);
        } finally {
            if (pdf != null)
                pdf.close();
        }
    }

    private String getPassword(final MultivaluedMap<String, String> parameters) {
        final String password = getParameterValue(parameters, PASSWORD, 0);
        return password == null ? StringUtils.EMPTY : password;
    }

    @Override
    public void parseContent(final MultivaluedMap<String, String> parameters, final InputStream inputStream,
            String extension, final String mimeType, final ParserResultBuilder resultBuilder) throws Exception {
        parseContent(PDDocument.load(inputStream, getPassword(parameters)), resultBuilder);
    }

    @Override
    public void parseContent(final MultivaluedMap<String, String> parameters, final Path filePath, String extension,
            final String mimeType, final ParserResultBuilder resultBuilder) throws Exception {
        parseContent(PDDocument.load(filePath.toFile(), getPassword(parameters)), resultBuilder);
    }

    @Override
    public ParserField[] getParameters() {
        return PARAMETERS;
    }

    @Override
    public ParserField[] getFields() {
        return FIELDS;
    }

    @Override
    public String[] getDefaultExtensions() {
        return DEFAULT_EXTENSIONS;
    }

    @Override
    public String[] getDefaultMimeTypes() {
        return DEFAULT_MIMETYPES;
    }

    public class Stripper extends PDFTextStripper {

        private final ParserResultBuilder resultBuilder;

        private Stripper(ParserResultBuilder resultBuilder) throws IOException {
            this.resultBuilder = resultBuilder;
        }

        @Override
        protected void endPage(PDPage page) throws IOException {
            super.endPage(page);
            final ParserFieldsBuilder document = resultBuilder.newDocument();
            final String text = output.toString();
            document.add(CHARACTER_COUNT, text.length());
            document.add(CONTENT, text);
            document.add(LANG_DETECTION, languageDetection(document, CONTENT, 10000));
            document.add(ROTATION, page.getRotation());
            output = new StringWriter();
        }
    }
}