io.konik.carriage.pdfbox.PDFBoxInvoiceExtractor.java Source code

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Here is the source code for io.konik.carriage.pdfbox.PDFBoxInvoiceExtractor.java

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/* Copyright (C) 2014 konik.io
 *
 * This file is part of the Konik library.
 *
 * The Konik library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * The Konik 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with the Konik library. If not, see <http://www.gnu.org/licenses/>.
 */
package io.konik.carriage.pdfbox;

import io.konik.carriage.utils.CallBackInputStream;
import io.konik.harness.FileExtractor;
import io.konik.harness.exception.InvoiceExtractionError;

import java.io.IOException;
import java.io.InputStream;

import javax.inject.Named;
import javax.inject.Singleton;

import org.apache.pdfbox.io.IOUtils;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentNameDictionary;
import org.apache.pdfbox.pdmodel.PDEmbeddedFilesNameTreeNode;
import org.apache.pdfbox.pdmodel.common.filespecification.PDComplexFileSpecification;

/**
 * The PDFBoxInvoice Extractor.
 */
@Named
@Singleton
public class PDFBoxInvoiceExtractor implements FileExtractor {

    static final String NO_FILE = "Provided PDF does not contain embedded files.";
    static final String NO_ZF_FILE = "The PDF does not contain an attached file named ZUGFeRD-invoice.xml. Error in: ";
    static final String ZF_FILE_NAME = "ZUGFeRD-invoice.xml";

    @Override
    public byte[] extract(InputStream pdfInput) {
        InputStream attachmentFile = null;
        try {
            attachmentFile = extractToStream(pdfInput);
            return IOUtils.toByteArray(attachmentFile);
        } catch (IOException e) {
            throw new InvoiceExtractionError("Error extracting content from PDF", e);
        } finally {
            IOUtils.closeQuietly(attachmentFile);
        }
    }

    @Override
    public InputStream extractToStream(InputStream pdfInput) {
        try {
            return extractIntern(pdfInput);
        } catch (IOException e) {
            throw new InvoiceExtractionError("Error extracting content from PDF", e);
        }
    }

    private static final InputStream extractIntern(InputStream pdfStream) throws IOException {
        PDDocument doc = PDDocument.load(pdfStream);
        InputStream inputStream = extractZugferdFileAttachment(doc);
        return new CallBackInputStream(inputStream, doc);
    }

    private static final InputStream extractZugferdFileAttachment(PDDocument doc) throws IOException {
        PDDocumentNameDictionary nameDictionary = new PDDocumentNameDictionary(doc.getDocumentCatalog());
        PDEmbeddedFilesNameTreeNode embeddedFiles = listEmbeddedFiles(nameDictionary);
        return extractZugferdXmlAttachment(embeddedFiles);
    }

    private static final PDEmbeddedFilesNameTreeNode listEmbeddedFiles(PDDocumentNameDictionary names) {
        PDEmbeddedFilesNameTreeNode embeddedFiles = names.getEmbeddedFiles();
        if (embeddedFiles == null) {
            throw new InvoiceExtractionError(NO_FILE);
        }
        return embeddedFiles;
    }

    private static final InputStream extractZugferdXmlAttachment(PDEmbeddedFilesNameTreeNode embeddedFiles)
            throws IOException {
        PDComplexFileSpecification fileSpec = (PDComplexFileSpecification) embeddedFiles.getValue(ZF_FILE_NAME);
        if (fileSpec == null) {
            throw new InvoiceExtractionError(NO_ZF_FILE + ZF_FILE_NAME);
        }
        return fileSpec.getEmbeddedFile().createInputStream();
    }

}