如何在REST API中强制执行日期值输入？

Question

The user needs to make a POST to /api/date with something like March 13, 2019 or 08/19/2020 . As long as it's a date, it should be accepted.

I have something like this (Using Dropwizard framework)

@POST
public void post(String date)
{
  validateDate(date);
  //continue
}

private void validateDate(String date)
{
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    try
    {
        LocalDateTime.parse(date, formatter);
    }
    catch (DateTimeParseException e)
    {
      //not a date
    }
}

I'm not sure if I'm in the right approach, there must be a better way to validate strings as dates.

Answer 1

EDIT: It is not really clear if you want to know how to validate dates correctly or how to handle invalid inputs to your REST API. My answer shows the latter.

You should use a return value for your post method. You can return javax.ws.rs.core.Response , with that you can control the HTTP code and response object you want to return.

On success, you would normally return the created object with a 200 success code. On failure, you would return an error code (like 400 Bad request) with a detailed error message ("Date must be in the format yyyy-MM-dd").

To create the response, you can use the ResponseBuilder.

Example:

Response.ok( yourObject ).build(); //success
Response.status( Status.BAD_REQUEST ).entity( yourErrorMessageObject ).build(); // failure

So I would change the code to this:

@POST
public Response post(String date)
{
  if(!isDateValid(date)){
     return Response.status( Status.BAD_REQUEST ).entity( buildErrorMessage()).build();
  }

  //continue
  Response.ok().build(); // returns nothing on success (like void)
}

private boolean isDateValid(String date)
{
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    try
    {
        LocalDateTime.parse(date, formatter);
        return true;
    }
    catch (DateTimeParseException e)
    {
      //not a date
      return false;
    }
}

Answer 2

You can accept multiple formats for a date time using the optional syntax ([<your format>])* . eg

DateTimeFormatter formatter = DateTimeFormatter.ofPattern(
    "[yyyy-MM-dd][dd-MM-yyyy][MMMM dd, yyyy]");