Handle time conversions from .NET APIs

time-conversions.swift

import Foundation

// Further Reading:

// https://technet.microsoft.com/en-us/library/aa258277(v=sql.80).aspx

// http://www.unicode.org/reports/tr35/tr35-31/tr35-dates.html#Date_Format_Patterns

// http://www.w3.org/TR/NOTE-datetime

// https://en.wikipedia.org/wiki/ISO_8601

extension Date {
    
    static func dateFromServerString(string: String) -> Date {
        // Handles difference between ISO-8601 & extended (MSSQL datetime and smalldatetime)
        
        let dateFormatter = DateFormatter()
        
        let regex = try! NSRegularExpression(pattern: "\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}:\\d{2}\\.", options:.caseInsensitive)
        
        let matches = regex.matches(in: string, options:[], range: NSMakeRange(0, NSString(string: string).length))
        
        dateFormatter.dateFormat = (matches.count >= 1) ? "YYYY-MM-dd'T'HH:mm:ss.SZ" : "YYYY-MM-dd'T'HH:mm:ssZ"
        
        return dateFormatter.date(from: string)!
    }
    
}


var serverDateBasic = Date.dateFromServerString(string: "2016-04-29T16:44:22Z")

var serverDateBasicTimeZone = Date.dateFromServerString(string: "2016-04-29T16:44:22-04:00")

var serverDateDecimal = Date.dateFromServerString(string: "2016-04-29T16:44:22.47894Z")

var serverDateDecimalTimeZone = Date.dateFromServerString(string: "2016-04-29T16:44:22.47894+01:00")



// DATE STRING FORMATS

let dateFormatter = DateFormatter()

var date = Date()


// ERA

dateFormatter.dateFormat = "G"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "GGGG"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "GGGGG"
dateFormatter.string(from: date)


// YEAR

dateFormatter.dateFormat = "y"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "Y"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "u" // Extended Year
dateFormatter.string(from: date)

dateFormatter.dateFormat = "U" // Cyclic Year
dateFormatter.string(from: date)

dateFormatter.dateFormat = "UUUU" // Cyclic Year
dateFormatter.string(from: date)

dateFormatter.dateFormat = "UUUUU" // Cyclic Year
dateFormatter.string(from: date)


// QUARTER

dateFormatter.dateFormat = "Q"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "QQQ"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "QQQQ"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "q" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "qqq" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "qqqq" // Stand-alone
dateFormatter.string(from: date)


// MONTH

dateFormatter.dateFormat = "M"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "MM"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "MMM"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "MMMM"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "MMMMM"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "L" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "LL" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "LLL" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "LLLL" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "LLLLL" // Stand-alone
dateFormatter.string(from: date)


// WEEK

dateFormatter.dateFormat = "w" // Week of year
dateFormatter.string(from: date)

dateFormatter.dateFormat = "W" // Week of month
dateFormatter.string(from: date)


// DAY

dateFormatter.dateFormat = "d" // Day of month
dateFormatter.string(from: date)

dateFormatter.dateFormat = "dd" // Day of month
dateFormatter.string(from: date)

dateFormatter.dateFormat = "D" // Day of year
dateFormatter.string(from: date)

dateFormatter.dateFormat = "DD" // Day of year
dateFormatter.string(from: date)

dateFormatter.dateFormat = "DDD" // Day of year
dateFormatter.string(from: date)

dateFormatter.dateFormat = "F" // Day of week in moth
dateFormatter.string(from: date)

dateFormatter.dateFormat = "g" // Modified Julian day
dateFormatter.string(from: date)


// WEEKDAY

dateFormatter.dateFormat = "E"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "EEEE"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "EEEEE"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "EEEEEE"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "c" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "ccc" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "cccc" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "ccccc" // Stand-alone
dateFormatter.string(from: date)

dateFormatter.dateFormat = "cccccc" // Stand-alone
dateFormatter.string(from: date)


// PERIOD

dateFormatter.dateFormat = "a"
dateFormatter.string(from: date)


// HOUR

dateFormatter.dateFormat = "h"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "hh"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "H"
dateFormatter.string(from: date)

dateFormatter.dateFormat = "HH"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "K"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "KK"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "k"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "kk"
dateFormatter.string(from:date)


// MINUTE

dateFormatter.dateFormat = "m"
dateFormatter.string(from:date)


// SECOND

dateFormatter.dateFormat = "s"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "ss"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "SSSSSSSS"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "ss.SSSSSSSS"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "A"
dateFormatter.string(from:date)


// TIME ZONES

dateFormatter.dateFormat = "z"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "zzzz"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "Z"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "ZZZZ"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "ZZZZZ"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "O"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "OOOO"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "v"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "vvvv"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "V"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "VV"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "VVV"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "VVVV"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "X"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "XX"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "XXX"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "XXXX"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "XXXXX"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "x"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "xx"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "xxx"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "xxxx"
dateFormatter.string(from:date)

dateFormatter.dateFormat = "xxxxx"
dateFormatter.string(from:date)