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How to validate the date and time in the url that is the correct DateTimeOffset format?

DateTimeOffset format (basically starts with 4 digits of year and end with uppercase Z):

  • yyyy-mm-ddZ
  • yyyy-mm-ddThh:mm:ssZ
  • yyyy-mm-ddThh:mm:ss.fffffZ

Valid DateTimeOffset in the url:

  • aaa.com/activityDateTime eq 2022-05-12Z
  • aaa.com/activityDateTime eq 2022-05-12T12:00:00Z
  • aaa.com/activityDateTime%20eq%202022-05-12T12:00:00Z
  • aaa.com/activityDateTime+eq+2022-05-12T12:00:00.123456Z
  • aaa.com/activityDateTime gt 2022-03-12Z le 2022-05-12Z

Note: eq means equal, gt means greater than, le means less than

Invalid DateTimeOffset in the url:

  • aaa.com/activityDateTime eq 2022-05-12
  • aaa.com/activityDateTime eq 2022-05-12T12:00:00
  • aaa.com/activityDateTime%20eq%202022-05-12T12:00:00
  • aaa.com/activityDateTime+eq+2022-05-12T12:00:00.123456

I'm currently convert the url to string and use Regex to validate it, but not sure what's the proper way to handle the case where url contains "%20". Is there a way not to use Replace()? Also, any other suggestions to validate DateTimeOffset in the url? Here's my current regex expression:

Regex checkDate = new Regex(@"^(?!\d{4}-\d{2}-\d{2}Z)");
Regex checkDateTime = new Regex(@"^(?!\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z)");
Lee Taylor
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S.P.
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    You can use [HttpUtility.UrlDecode](https://learn.microsoft.com/en-us/dotnet/api/system.web.httputility.urldecode?view=net-6.0) to get rid of the %20 – GuyVdN May 12 '22 at 22:23
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    I'd take a step back and question why you're using Regex and why you're doing it on a URL string. It looks like you're using C#: why not parse the URL with the `Uri` class and try to parse the DateTimeOffset with the `DateTimeOffset` class? In fact, it looks like you're using `OData`: why not use [OdataUriParser](https://learn.microsoft.com/en-us/odata/odatalib/use-uri-parser)? OData [follows a standard](https://www.odata.org/documentation/odata-version-2-0/overview/) for formatting DateTimeOffset: if possible you should use that rather than write your own regex. – StriplingWarrior May 12 '22 at 22:27
  • Thank you @GuyVdN, I completely forgot that I can use it. – S.P. May 15 '22 at 13:41
  • Thanks @StriplingWarrior this is a very solid suggestion, I'm new to Odata and I will look into those! – S.P. May 15 '22 at 13:42

1 Answers1

1

If you need a regex to validate DateTimeOffset, you can use the following one:

^[A-Za-z\.\/]+( |%20|\+)(eq|gt)( |%20|\+)[\d\-]+(T[\d:]+(\.[\d]+)?Z|Z( [a-z]+ [\d\-]+Z)?)$

Explanation:

  • ^: start string
  • [A-Za-z\.\/]+: any combination of alphabetic character, dots and slashes
  • ( |%20|\+): single space or %20 or +
  • (eq|gt): eq or gt
  • ( |%20|\+): single space or %20 or +
  • [\d\-]+: any combination of digits and dashes (the date)

The last part (T[\d:]+(\.[\d]+)?Z|Z( [a-z]+ [\d\-]+Z)?) can match one between two different suffixes.

Suffix 1 T[\d:]+(\.[\d]+)?Z:

  • T: T
  • [\d:]+: any combination of digits and : (the time)
  • (\.[\d]+)?: optional presence of single dot with a combination of digits (milliseconds?)
  • Z: Z

Suffix 2 Z( [a-z]+ [\d\-]+Z)?:

  • Z: Z
  • ( [a-z]+ [\d\-]+Z)?: optional presence of a space, followed by letters, a space, combination of digits and dashes (a date), a Z

The whole regex is wrapped up with:

  • $: end of string

If instead you want to match only the DateTimeOffset, use only the following part of this regex:

[\d\-]+(T[\d:]+(\.[\d]+)?Z|Z( [a-z]+ [\d\-]+Z)?)$

Test this regex here.

lemon
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  • Thanks! I will look into OData more but really appreciate your Regex suggestion! – S.P. May 15 '22 at 13:43
  • Glad it was helpful! If this answer solves your problem, make sure to update your question as answered to save devs' time for other yet open problems. @S.P. – lemon May 15 '22 at 13:46