itk/readImageLocalFile.js

High performance spatial analysis in a JavaScript runtime environment.

var path = require('path');

var mime = require('mime-types');

var mimeToIO = require('./MimeToImageIO.js');

var getFileExtension = require('./getFileExtension.js');

var extensionToIO = require('./extensionToImageIO.js');

var ImageIOIndex = require('./ImageIOIndex.js');

var loadEmscriptenModule = require('./loadEmscriptenModuleNode.js');

var readImageEmscriptenFSFile = require('./readImageEmscriptenFSFile.js');
/**
 * Read an image from a file on the local filesystem in Node.js.
 *
 * @param: filePath path to the file on the local filesystem.
 */


var readImageLocalFile = function readImageLocalFile(filePath) {
  return new Promise(function (resolve, reject) {
    var imageIOsPath = path.resolve(__dirname, 'ImageIOs');
    var absoluteFilePath = path.resolve(filePath);

    try {
      var mimeType = mime.lookup(absoluteFilePath);
      var extension = getFileExtension(absoluteFilePath);
      var io = null;

      if (mimeToIO.has(mimeType)) {
        io = mimeToIO.get(mimeType);
      } else if (extensionToIO.has(extension)) {
        io = extensionToIO.get(extension);
      } else {
        for (var idx = 0; idx < ImageIOIndex.length; ++idx) {
          var _modulePath = path.join(imageIOsPath, ImageIOIndex[idx]);

          var _Module = loadEmscriptenModule(_modulePath);

          var imageIO = new _Module.ITKImageIO();

          var _mountedFilePath = _Module.mountContainingDirectory(absoluteFilePath);

          imageIO.SetFileName(_mountedFilePath);

          if (imageIO.CanReadFile(_mountedFilePath)) {
            io = ImageIOIndex[idx];

            _Module.unmountContainingDirectory(_mountedFilePath);

            break;
          }

          _Module.unmountContainingDirectory(_mountedFilePath);
        }
      }

      if (io === null) {
        reject(Error('Could not find IO for: ' + absoluteFilePath));
      }

      var modulePath = path.join(imageIOsPath, io);
      var Module = loadEmscriptenModule(modulePath);
      var mountedFilePath = Module.mountContainingDirectory(absoluteFilePath);
      var image = readImageEmscriptenFSFile(Module, mountedFilePath);
      Module.unmountContainingDirectory(mountedFilePath);
      resolve(image);
    } catch (err) {
      reject(err);
    }
  });
};

module.exports = readImageLocalFile;