Server side Validation for DateTime Stamp

Question

In my application, server side date validations were done through IsDate which is very inconsistent in behavior. I used isValid("USdate",DateVar), that works fine with incoming dates, but when DateVar is a date time stamp it fails. Values coming in DateVar could be anything, a date, a time, a date & time or even some invalid data. If I use Date mask with isValid, that behaves like isDate and of no use. How I can accomplish this.

Answer 1

All "dates" that will be arriving via a request - be they via a URL parameter, a form submission, a cookie, etc - will be strings, not dates.

What you need to do is to work out what string formats you will allow, and validate them accordingly.

EG: you might decide that yyyy-mm-dd is OK, but you won't accept m/d/yy. You might pass them as three separate components for y, m and d. But you really oughtn't try to accept any old format, as you will need to have a validator for each format, and there's a law of diminishing returns there: people won't expect to use any format they like; they'll be expecting you to guide them. You also need to be mindful that if you ask me to type in today's date, I'd give you 4/5/2015. But to you that might represent April 5.

Given various month-length and leap-year rules, really the easiest and most reliable way to see if and input string represents a date in an acceptable format do this:

• Validate the format mask, eg: if you're accepting yyyy-mm-dd, then the input needs to be \d{4}-\d{2}-\d{2}. Then at least you know the string has been formed properly.
• Then extract the components from the string, and attempt to create a date object with them. If it doesn't error: it's OK.
• Last: check any date boundaries within / outwith which the date needs to fall.