@cleerlycode/cornerstone-wado-image-loader/src/imageLoader/wadors/loadImage.js

Cornerstone ImageLoader for DICOM WADO-URI

import metaDataManager from './metaDataManager.js';
import getPixelData from './getPixelData.js';
import createImage from '../createImage.js';

/**
 * Helper method to extract the transfer-syntax from the response of the server.
 * @param {string} contentType The value of the content-type header as returned by the WADO-RS server.
 * @return The transfer-syntax as announced by the server, or Implicit Little Endian by default.
 */
export function getTransferSyntaxForContentType (contentType) {
  let transferSyntax = '1.2.840.10008.1.2'; // Default is Implicit Little Endian.

  if (contentType) {
    // Browse through the content type parameters
    const parameters = contentType.split(';');

    for (const parameterIndex in parameters) {
      let parameter = parameters[parameterIndex];
       
      // Look for a transfer-syntax=XXXX pair
      const parameterValues = parameter.split('=');

      if (parameterValues.length !== 2) {
        continue;
      }

      if (parameterValues[0].trim() === 'transfer-syntax') {
        transferSyntax = parameterValues[1].trim() || transferSyntax;
      }
    }
  }

  return transferSyntax;
}

function loadImage (imageId, options) {
  const start = new Date().getTime();
  const uri = imageId.substring(7);

  const promise = new Promise((resolve, reject) => {
    // check to make sure we have metadata for this imageId
    const metaData = metaDataManager.get(imageId);

    if (metaData === undefined) {
      const error = new Error(`no metadata for imageId ${imageId}`);

      return reject(error);
    }

    // TODO: load bulk data items that we might need
    const mediaType = 'multipart/related; type="application/octet-stream"'; // 'image/dicom+jp2';

    // get the pixel data from the server
    getPixelData(uri, imageId, mediaType).then((result) => {
      const transferSyntax = getTransferSyntaxForContentType(result.contentType);
      const pixelData = result.imageFrame.pixelData;
      const imagePromise = createImage(imageId, pixelData, transferSyntax, options);

      imagePromise.then((image) => {
        // add the loadTimeInMS property
        const end = new Date().getTime();

        image.loadTimeInMS = end - start;
        resolve(image);
      }, reject);
    }, reject);
  });

  return {
    promise,
    cancelFn: undefined
  };
}

export default loadImage;