code: public static void setFileProperties (final File file, final String contentType) throws IOException, FrameworkException {
  
  		final java.io.File fileOnDisk = file.getFileOnDisk(false);
  		final PropertyMap map         = new PropertyMap();
  
  		map.put(StructrApp.key(File.class, "contentType"), contentType != null ? contentType : FileHelper.getContentMimeType(fileOnDisk, file.getProperty(File.name)));
  		map.put(StructrApp.key(File.class, "size"),        FileHelper.getSize(fileOnDisk));
  		map.put(StructrApp.key(File.class, "version"),     1);
  
  		map.putAll(getChecksums(file, fileOnDisk));
  
  		file.setProperties(file.getSecurityContext(), map);
  	}
docs: Set the contentType, checksum, size and version properties of the given fileNode
  
  @param file
  @param contentType if null, try to auto-detect content type
  @throws FrameworkException
  @throws IOException