Handling timezones and daylight savings can be a nightmare. Such a 'simple' concept makes everyone gang up on each other. DateTime can be your friend, although, it can bite you in the butt when you deploy your code to an OS doesn't use the same TimeZoneInfo. DateTime does magic when it parses, serializes, etc, by auto converting to the local time for you...
I work in the Eastern Timezone. But when I deploy to AWS Lambda... it's UTC/GMT time. So DateTime.Now gives me two different values (notice how there is NO hour offset):
var local = DateTime.Now.ToString(); //2020-01-29T08:56:01.411
var aws = DateTime.Now.ToString(); //2020-01-29T13:56:01.393Makes it very difficult to manage, especially if you have time sensitive requirements, and the requirements are (indirectly) given in for a specific timezone.
All this magic library is it takes a time and owns understanding daylight savings time, and hour offset from UTC. It also allows for easy operator logic.
var easternNow = EasternDateTime.Now;var easternTodayAt755pm = new EasternDateTime(TimeSpan.Parse("19:55")); //timespan for today @ this hour
var christmasAtNoon = new EasternDateTime(2020, 12, 25, 12, 0, 0); //specific day at this time in ET
var easternDateTime = new EasternDateTime(632039429000000); //ticksvar easternNowAsString = EasternDateTime.Now.ToString(); //2020-01-29T08:56:01.411-05:00var eastern11am = new EasternDateTime(TimeSpan.Parse("11:00"));
var eastern545pm = new EasternDateTime(TimeSpan.Parse("17:45"));
var utcNow = DateTime.UtcNow;
var utcfor1145eastern = DateTime.Parse($"{utcDate.Year}-{utcDate.Month}-{utcDate.Day}T16:45:00.000+00:00");
var isBetween = (eastern11am < utcfor1145eastern) && (eastern545pm >= utcfor1145eastern); //truevar utcTime = EasternDateTime.Now.ToUniversalTime(); var central = CentralDateTime.Now;
var mountain = MountainDateTime.Now;
var pacific = PacificDateTime.Now;
var alaska = AlaskaDateTime.Now;
var hawaii = HawaiiDateTime.Now;
var universal = UniversalDateTime.Now;
Yep. I know. Thats the disadvantage to the object type design pattern. I set up this library to use both Newtonsoft and System.Text.Json converters (at the attribute level) to serialize and deserialize the DateTime string we all know and use. But when it comes to Swagger model definitions... it still treats these object types like objects. If you follow my Hein.Swagger repository, you can only imagine I like my API documentation to match the output from the API.
To do this you need to create/register the object type in the swagger defintion. You can do so by doing something like this:
services.AddSwaggerGen(x =>
{
x.SwaggerDoc("v1", new OpenApiInfo
{
Title = "My API"
});
//registering the DateTime type you will be using as a string/date-time
x.MapType<EasternDateTime>(() =>
new OpenApiSchema() { Type = "string", Format = "date-time" });
});Enjoy