I have an API call that asks me to convert dates to timeIntervalSince1970 in ms and they also want me to add the correct time zone difference. So my code is at the moment:
if let timeStamp = incident?.publishedTimeStamp as Date? {
let roundedDown = Int(timeStamp.timeIntervalSince1970 * 1000)
publishedDate = String(roundedDown)
}
This gives me a number that if I insert it in here:
https://www.epochconverter.com/
I get this result:
Now as you can see, the GMT time (the top result) is what I at the moment achieve. I need to add enough ms so that the Your time zone section would be in the GMT section. I hope this makes sense.
So how can I get the number in ms that represents the difference between the current time zone from GMT so I can sum it with my current result?
var roundedDown = Double(TimeZone.current.secondsFromGMT(for: timeStamp)) + timeStamp.timeIntervalSince1970
roundedDown *= 1000
publishedDate = String(Int(roundedDown))
Related
I am storing dates from a Swift Project in Firestore without any problem. Dates are converted into UTC format and stored in Firestore as a Timestamp. All good.
Then, back on clientside, I can read them back and apply the TimeZone.current and the date/time are adjusted accordingly based on the timezone the user is currently in.
So, as en example, a time originally of:
9:00 pm Melbourne time (which is GMT+10),
shows as 7:00 am if the user is in New York.
Great.
But I have some items that I want to adjust for timezones (as per above) and others I don't.
So say I have two items the same as the above example, but one is an alarm and I want to keep at the time it was originally set for regardless of the new timezone... So still keep it at 9:00 pm.
I have a Bool flag saved in my database to say ignoreTimezone but I'm lost as to how to do this in Swift when reading back the timestamp from Firestore in UTC format and get it back to the original 9:00 pm.
All the Q&A's I've found are all about converting timezones etc. but not really on this example of ignoring one and keeping the date and time set to the timezone they were originally set for.
Thanks in advance for any help and/or suggestions.
Question updated as recommended
I have now incorporated the suggested code. So have a calendar extension:
extension Calendar {
func offsetFromMidnight(for date: Date) -> TimeInterval {
return date.timeIntervalSince(startOfDay(for: date))
}
}
Then I carry out the recommended steps.
Take an offset from midnight, in this case, the current Date():
let offsetSinceMidnight = UInt64(Calendar.current.offsetFromMidnight(for: Date()))
This value is then stored on the server.
I'm currently in Melbourne (Australia), so the date and time item used for testing is July 9 # 2:00pm.
When it is retrieved on the client end in a different timezone, I'm using the recommended code:
//Create a calendar for the target timezone
guard let chicagoTimeZone = TimeZone(identifier: "America/Chicago") else { fatalError() }
var chicagoCalendar = Calendar(identifier: .gregorian)
chicagoCalendar.timeZone = chicagoTimeZone
//Calculate midngiht in the target calendar
let chicagoMidnight = chicagoCalendar.startOfDay(for: Date())
//calculate the same time-of-day in the new timezone
let adjustedChicagoTime = Date(timeInterval: TimeInterval(offsetSinceMidnight), since: chicagoMidnight)
The output is set to the correct time, 2:00pm in Chicago, but because of the differnent dates (Chicago is still July 8th), then the midnight timeinterval is being applied on the wrong date. So I get July 8 # 2:00pm.
I'm assuming I will also need to capture the original date components to apply the offsetSinceMidnight to a date in the newTimeZone that has matching date components??? Or is there a better approach to this?
Date objects store an instant in time, anywhere in the world. They don't capture the idea of a time-of-day regardless of time zone.
To do that I would suggest calculating an offsetFromMidnight value.
Edited to fix return value.
extension Calendar {
func offsetFromMidnight(for date: Date) -> TimeInterval {
return date.timeIntervalSince(startOfDay(for: date))
}
}
You'd call that function in the user's current calendar to get the seconds since midnight in the user's current time zone. Save that to your database. (You could round to a long integer with very little loss of precision.)
I happen to BE in the NYT time zone (EDT) so using that as the destination time zone won't work for me since it won't change anything. Instead, I'll show code to convert from my timezone to GMT:
//Run on user's local machine (in EDT in my case):
let offsetSinceMidnight = UInt64(Calendar.current.offsetFromMidnight(for: Date()))
//Save offset to FireStore
Then if you want that same time of day in a new timezone, you'd use code like this:
//Create a calendar for the target time zone (or the user's local time zone on the destination machine)
guard let gmt = TimeZone(abbreviation: "GMT") else { fatalError() }
var gmtCalendar = Calendar(identifier: .gregorian)
gmtCalendar.timeZone = gmt
//Read time offset from FireStore
let offsetFromNYC = Calendar.current.offsetFromMidnight(for: Date())
//Calculate midnight in target calendar
let gmtMidnight = gmtCalendar.startOfDay(for: Date())
//Calculate the same time-of-day in the GMT time zone
let gmtTimeToday = Date(timeInterval: TimeInterval(offsetSinceMidnight), since: gmtMidnight)
print(gmtTimeToday)
Note that the above will give you the same hours/minutes/seconds as the offsetFromMidnight time.
Edit:
If your goal is to set an alarm to the next future time-of-day in the local time zone, you'd need to add logic to check if the computed date/time is in the past and adjust:
//Change adjustedChicagoTime to a var
var adjustedChicagoTime = Date(timeInterval: TimeInterval(offsetSinceMidnight), since: chicagoMidnight)
//If the alarm time is in the past, add a day to the date.
if adjustedChicagoTime < Date() {
adjustedChicagoTime = Calendar.current.date(byAdding: .day,
value: 1, to: adjustedChicagoTime, wrappingComponents: false)
}
Edit #2:
After a back-and-forth, it sounds like you sometimes want to save a date and time that's independent of time zone, like 9:30 AM on 10 July. If I create that date in EDT, and you view it in Melborne, it's ALWAYS 9:30 AM on 10 July.
Other times, you want to upload and download dates & times that honor time zones.
In order to easily do both, I would suggest saving 2 different string date/time fields to FireStore, one with a time zone, and one without. The one with timezone (or rather offset from GMT) would capture a moment in time around the world, and could be converted to a local time.
The one without time zone would describe a day/month/year/hours/minutes in local time.
You could generate/parse those strings in Swift using date formatters like this:
let baseFormatString = "YYYY-MM-dd'T'HH:mm"
let timeZoneFormatString = baseFormatString + "ZZZ"
let noTimeZoneFormatter = DateFormatter()
noTimeZoneFormatter.dateFormat = baseFormatString
let timeZoneFormatter = DateFormatter()
timeZoneFormatter.dateFormat = timeZoneFormatString
Note that by default a date formatter uses the system's time zone, so the "no time zone formatter" would assume the local time zone. If you use it to convert a date string to a date, it will assume the date is in the local time zone.
I don't understand why this date is saved as +1 day:
startdate = "2017-11-29T23:59:59.999Z";
var new_date = moment(startdate).format('DD/MM/YYYY'); // --> gives 30/11/2017
But if I do:
startdate = "2017-11-29";
var new_date = moment(startdate).format('DD/MM/YYYY'); // --> gives the correct date 29/11/2017
Any ideas?
Here is a jsfiddle showing this: http://jsfiddle.net/jbgUt/416/
Thanks!
If a time part is included, an offset from UTC can also be included as +-HH:mm, +-HHmm, +-HH or Z.
Add utc() to avoid it.
moment(startdate).utc().format('DD-MM-YYYY')
or
moment.utc(startdate).format('DD-MM-YYYY')
If you want to parse or display a moment in UTC, you can use moment.utc() instead of moment()
Late to the party on this one, but I did just convert a few of our product's date-time objects to https://moment.github.io/luxon/
Takes out the need for the .utc() method above.
I have a timestamp like "1461819600". The I execute this code in a distributed environment as val campaign_startdate_year: String = Utils.getYear(campaign_startdate_timestamp).toString
The problem is that I always get the same year 1970. Which might be the reason of it?
import com.github.nscala_time.time.Imports._
def getYear(timestamp: Any): Int = {
var dt = 2017
if (!timestamp.toString.isEmpty)
{
dt = new DateTime(timestamp.toString.toLong).getYear // toLong should be multiplied by 1000 to get millisecond value
}
dt
}
The same issue occurs when I want to get a day of a month. I get 17 instead of 28.
def getDay(timestamp: Any): Int = {
var dt = 1
if (!timestamp.toString.isEmpty)
{
dt = new DateTime(timestamp.toString.toLong).getDayOfYear
}
dt
}
The timestamp you have is a number of seconds since 01-01-1970, 00:00:00 UTC.
Java (and Scala) usually use timestamps that are a number of milliseconds since 01-01-1970, 00:00:00 UTC.
In other words, you need to multiply the number with 1000.
The timestamp that you have seems to be in seconds since the epoch (i.e. a Unix timestamp). Java time utilities expect the timestamp to be in milliseconds.
Just multiply that value by 1000 and you should get the expected results.
You can rely on either on spark sql function which have some date utilities (get year/month/day, add day/month) or you can use JodaTime library to have more control over Date and DateTime, like in my answer here: How to replace in values in spark dataframes after recalculations?
I creating an application, for that I need to find data by month using JPA and java.time.LocalDate. So, is it possible to retrieve data by month from mysql?
Thanks in advance for help.
First find start and end date of month and use between method of JPA to find data of current month.
LocalDate start = LocalDate.ofEpochDay(System.currentTimeMillis() / (24 * 60 * 60 * 1000) ).withDayOfMonth(1);
LocalDate end = LocalDate.ofEpochDay(System.currentTimeMillis() / (24 * 60 * 60 * 1000) ).plusMonths(1).withDayOfMonth(1).minusDays(1);
In Repository
List<Object> findByCreatedateGreaterThanAndCreatedateLessThan(LocalDate start,LocalDate end);
Its better to use the between keyword, it makes things allot shorter.
List<Object> findByCreatedateBetween(LocalDate start,LocalDate end);
Also if you want to use the LocalDate or LocalDateTime objects with Spring Data you should use the converter class Jsr310JpaConverters or else the documents will be stored as Blobs instead of Dates (which is bad for portability of the database). Please see this tutorial on how to implement the Converter.
https://www.mkyong.com/spring-boot/spring-boot-spring-data-jpa-java-8-date-and-time-jsr310/
tl;dr
YearMonth.now( ZoneId.of( "Pacific/Auckland" ) ) // Get current month for particular time zone.
.atDayOfMonth( 1 ) // Get the first date of that month.
.plusMonths( 1 ) // Get first of next month for Half-Open query.
Details
Assuming your column in MySQL is of DATE type…
LocalDate
The LocalDate class represents a date-only value without time-of-day and without time zone.
Time zone
A time zone is crucial in determining a date. For any given moment, the date varies around the globe by zone. For example, a few minutes after midnight in Paris France is a new day while still “yesterday” in Montréal Québec.
Specify a proper time zone name in the format of continent/region, such as America/Montreal, Africa/Casablanca, or Pacific/Auckland. Never use the 3-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!).
ZoneId z = ZoneId.of( "America/Montreal" );
LocalDate today = LocalDate.now( z );
YearMonth
The YearMonth class represents an entire month. Getting the current month requires a time zone as discussed above. Around the beginning/ending of the month, the current moment could be “next” month in Auckland New Zealand while still “previous” month in Kolkata India.
YearMonth currentMonth = YearMonth.now( z ) ;
Get the first date of the month.
LocalDate start = currentMonth.atDayOfMonth( 1 ) ;
Half-Open
Generally best to use the Half-Open [) approach to defining a span of time, where the beginning is inclusive while the ending is exclusive. So defining a month means starting with the first date of the month and running up to, but not including, the first date of the following month.
LocalDate stop = start.plusMonths( 1 ) ;
Query
Do not use the BETWEEN command in SQL as it is fully closed [], both beginning and ending being inclusive. Half-Open uses >= & < logic.
SELECT when FROM tbl
WHERE when >= start
AND when < stop
;
it's also useful
#Query("from PogWorkTime p where p.codePto = :codePto and month(p.dateApply) = :month and year(p.dateApply) = :year")
Iterable<PtoExceptWorkTime> findByCodePtoAndDateApply_MonthAndDateApply_Year(#Param("codePto") String codePto,#Param("month") int month, #Param("year") int year);
I have a spreadsheet that asks people to enter in a day of the month when we need to send out a bill. What I want to do is create a calendar event based on that. So, essentially what I need is an event that starts at the current month, day from the spreadsheet, and continues to a specified point in time.
var monthlyDate = row[6]; // Seventh column, monthly date of payment
var curDate = new Date();
var curMonth = curDate.getMonth();
var curYear = curDate.getYear();
curDate.setDate(curMonth, monthlyDate, curYear);
Logger.log("Day of month: %s", monthlyDate);
Logger.log("Current Date: %s", curDate);
Logger.log("Current Date: %s", Date());
What I'm seeing is that the monthly date is coming in as a float "6.0" for example, and no matter what I enter in for monthlyDate in the setDate line, it keeps setting the date to 10/9/15 (Today is 10/15/15). I've hard-coded that value to many different numbers, but for some reason it's just not working.
How can I create a date (in any format) that follows the scheme "Current Month / Day from Speadsheet / Current Year" ?
The getMonth() method returns a "zero-indexed" number. So, it returns the number 9 for the 10th month. setDate() doesn't set the date, it sets the "Day of the Month". The name of that method is misleading.
Documentation - setDate()
So, the last two parameters that you are using in setDate() are doing nothing. You are setting the day of the month to 9.
If you want to set multiple date parameters at the same time, you need to use the new Date() method:
var d = new Date(year, month, day, hours, minutes, seconds, milliseconds);
The month parameter accept values from 0 to 11, 0 is Jan and 11 is Dec
Date Reference