DICOM Encapsulated PDF dataset generator for Node.js

dcmjs-pdf-gen.js

// dcmjs-pdf-gen
// This Node.js utility can generate DICOM Encapsulated PDF datasets,
// for testing purposes.

// The following npm packages are required:
// dcmjs
// faker
// moment
// e.g. npm install dcmjs faker@5.5.3 moment

// Usage:
// [OPTIONS] node dcmjs-pdf-gen.js
// [OPTIONS]:
// PDF_FILE: The file path of the PDF document to encapsulate.
// OUTPUT_FILE: Output file path (default: pdf.dcm).
// e.g. PDF_FILE=test.pdf node dcmjs-pdf-gen.js

const fs = require('fs');

const faker = require('faker');
const moment = require('moment');

const dcmjs = require('dcmjs');
const { DicomMetaDictionary, DicomDict } = dcmjs.data;

//////////////////////////////////////////////////////////////////////////
// Constant UIDs
/**
 * Encapsulated PDF Storage SOP class UID.
 * @constant {string}
 */
const EncapsulatedPdfSopClassUid = '1.2.840.10008.5.1.4.1.1.104.1';

/**
 * Explicit VR Little Endian syntax UID.
 * @constant {string}
 */
const ExplicitVrLittleEndianTransferSyntaxUid = '1.2.840.10008.1.2.1';

/**
 * Implementation UID (using fo-dicom's!).
 * @constant {string}
 */
const ImplementationUid = '1.3.6.1.4.1.30071.8';

//////////////////////////////////////////////////////////////////////////
// Functions
/**
 * Generates a DICOM PDF dataset.
 * @method
 * @param {Buffer} pdfFileBuffer - The buffer of the PDF document to encapsulate.
 * @returns {Buffer} The DICOM PDF dataset buffer.
 */
function generatePdfDataset(pdfFileBuffer) {
  // Create dataset dates and times
  const birthDate = `${moment(faker.date.between('1950-01-01', '2000-01-01')).format('YYYYMMDD')}`;
  const date = `${moment(faker.date.between('1950-01-01', '2010-01-01')).format('YYYYMMDD')}`;
  const time = '000000';

  // Create dataset UIDs
  const studyInstanceUid = DicomMetaDictionary.uid();
  const seriesInstanceUid = DicomMetaDictionary.uid();
  const sopInstanceUid = DicomMetaDictionary.uid();

  // Pad PDF buffer
  let pdfBuffer = pdfFileBuffer;
  if (pdfBuffer.length & 1) {
    pdfBuffer = Buffer.concat([pdfBuffer, Buffer.from([0x00])]);
  }

  const dataset = {
    _vrMap: {
      EncapsulatedDocument: 'OB',
    },
    _meta: {
      _vrMap: {},
      FileMetaInformationVersion: new Uint8Array([0, 1]).buffer,
      MediaStorageSOPClassUID: EncapsulatedPdfSopClassUid,
      MediaStorageSOPInstanceUID: sopInstanceUid,
      TransferSyntaxUID: ExplicitVrLittleEndianTransferSyntaxUid,
      ImplementationClassUID: ImplementationUid,
    },

    // Patient Module Attributes
    PatientID: `${faker.random.alphaNumeric(6).toUpperCase()}`,
    PatientName: `${faker.name.firstName().toUpperCase()}^${faker.name.lastName().toUpperCase()}`,
    PatientBirthDate: birthDate,
    PatientSex: 'O',

    // General Study Module Attributes
    StudyInstanceUID: studyInstanceUid,
    StudyDate: date,
    StudyTime: time,
    StudyID: `${faker.random.alphaNumeric(3).toUpperCase()}`,
    AccessionNumber: `${faker.random.alphaNumeric(6).toUpperCase()}`,
    ReferringPhysicianName: `${faker.name.firstName().toUpperCase()}^${faker.name
      .lastName()
      .toUpperCase()}`,

    // Encapsulated Document Series Module Attributes
    Modality: 'DOC',
    SeriesInstanceUID: seriesInstanceUid,
    SeriesNumber: `${faker.datatype.number(100)}`,

    // General/SC Equipment Module Attributes
    Manufacturer: `${faker.company.companyName().toUpperCase()}`,
    ManufacturerModelName: `${faker.commerce.productName().toUpperCase()}`,
    DeviceSerialNumber: `${faker.random.alphaNumeric(6).toUpperCase()}`,
    SoftwareVersions: `${faker.random.alphaNumeric(1).toUpperCase()}.${faker.random
      .alphaNumeric(2)
      .toUpperCase()}`,
    ConversionType: 'WSD',

    // Encapsulated Document Module Attributes
    InstanceNumber: '1',
    AcquisitionDateTime: `${date}${time}`,
    ContentDate: date,
    ContentTime: time,
    DocumentTitle: '',
    BurnedInAnnotation: 'YES',
    MIMETypeOfEncapsulatedDocument: 'application/pdf',
    EncapsulatedDocument: [pdfBuffer.buffer],
    ConceptNameCodeSequence: [],

    // SOP Common Module Attributes
    SOPClassUID: EncapsulatedPdfSopClassUid,
    SOPInstanceUID: sopInstanceUid,
    SpecificCharacterSet: 'ISO_IR 100',
  };

  // Convert the JSON dataset into a DICOM part10 file
  const denaturalizedMetaHeader = DicomMetaDictionary.denaturalizeDataset(dataset._meta);
  const dicomDict = new DicomDict(denaturalizedMetaHeader);
  dicomDict.dict = DicomMetaDictionary.denaturalizeDataset(dataset);

  return Buffer.from(dicomDict.write({ fragmentMultiframe: false }));
}

//////////////////////////////////////////////////////////////////////////
// Gather params
const pdfFile = process.env.PDF_FILE;
if (!pdfFile) {
  throw new Error(
    'Provide the path of the PDF document to encapsulate through the PDF_FILE variable'
  );
}
const outFile = process.env.OUTPUT_FILE || 'pdf.dcm';

//////////////////////////////////////////////////////////////////////////
// Validate PDF
const pdfFileBuffer = fs.readFileSync(pdfFile);
const pdfFileBufferHeader = pdfFileBuffer.slice(0, 8).toString();
var pdfHeaderRegex = new RegExp('%PDF-1.[0-7]');
if (!pdfFileBufferHeader.match(pdfHeaderRegex)) {
  throw new Error(`The provided PDF file header is not valid [${pdfFileBufferHeader}]`);
}

//////////////////////////////////////////////////////////////////////////
// Generate PDF dataset and persist it to file
const pdfDatasetBuffer = generatePdfDataset(pdfFileBuffer);
fs.writeFileSync(outFile, pdfDatasetBuffer);