jooby/src/main/java/org/jooby/MediaType.java
public static Optional<MediaType> byFile(final File file) {
    requireNonNull(file, "A file is required.");
    return byPath(file.getName());
  }
public static Optional<MediaType> byFile(final File file) {
    requireNonNull(file, "A file is required.");
    return byPath(file.getName());
  }
Get a {@link MediaType} for a file.

@param file A candidate file.
@return A {@link MediaType} or {@link MediaType#octetstream} for unknown file extensions.