I have an ajax call, which returns datetime. Javascript displays it using client timezone. I not need in any client timezone, I want to show datetime the same as server return. Is it possible?
I get date via:
var d = eval('new' + date.replace(/\//g, ' '));
First off, there's no reason to use eval here (or almost anywhere), and generally lots of reasons not to.
JavaScript has only "local" time (the timezone of the client) and UTC (universal coordinated time, effectively the same as GMT). So your best bet normally is to have the server send you the time in UTC. But in your case, since you want to display the date in the server's timezone, it doesn't really matter whether JavaScript thinks the date is in local time or server time, and it's fine to send it in the server's timezone.
Note that when parsing date strings, JavaScript only recently (as of ECMAScript5) got a standard format for date strings, which is a simplified version of ISO-8601. Details here. Note that some older browsers will not yet support that format.
It's impossible to offer much more guidance without an example of what you're trying to parse.
Diodeus' suggestion also seems to me to make a lot of sense: If you want the date to be displayed in the server's timezone and format, just display the string you're given without interpreting it (again, subject to what the string looks like; I can't immediately come up with a reasonable format that would work with your posted code).
Related
I have an admin panel where items entered will have a time_posted and an expiration time. These times use a timestamp (time()) upon being entered.
I want the entering of the expiration time to use a fancy date/time selector, but the selector uses JavaScript client time rather than server time.
A way to fix this would be to save the timezone a user is in, then use that as offset for the data entered, but it's something that has to be 100% correct.
Is there any 'proper' way to approach this? I saw that some PHP functions do use the timezone setting but others do not, for instance the actual time() function doesn't and even if I create a DateTime object, output the current timestamp, change the timezone and output the timestamp again it just returns the same timestamp twice.
Any pointers would be lovely
I assume that the actual timestamp value would still be correct (independent) regardless of what settings/timezone the end user has.
Problems may apper when/if you want to generate date strings server-side and thus return times with offsets.
Either
1. dont generate date strings server side, if you are not sure about the timezone offsets or
2. warn users and make sure that they specify their timezone and then force that timezone whenever you output date string from timestamps
A few things:
You probably don't need to identify the user's time zone for the scenario you describe, but if you did then please recognize that a time zone and an offset are two different things. See "time zone != offset" in the timezone tag wiki. If you actually think you need the user's time zone (such as "America/Los_Angeles"), then refer to this answer.
If you want the entered date to be relative to the client's local time zone, then you need to use either a Date object, or a library like moment.js in JavaScript. Use the individual date/time components from the date picker to get either a unix timestamp, or an ISO8601 formatted date/time string at UTC. For example, "2016-09-02T01:23:45Z"
If you want the entered date to be relative to some other time zone, then you need to transmit the actual values the client entered without modification. The best way is in ISO8601 format without offset. For example, "2016-09-02T08:00:00". On the server side, parse that value and apply whatever time zone is applicable.
If you are only selecting a date, and not a time, then you should really think about whether any time is applicable or not. Is 00:00 really applicable? Or should it be 24:00 or 23:59:59.999? If you don't care about the user's time zone, then really you shouldn't assign any time value at all. Just pass the date. For example: "2016-09-02"
Don't rely on the server's time zone setting to be anything in particular. Though PHP has functionality for setting a "default" time zone, you should try to avoid using it. It is much safer to be explicit about time zones on a per-operation basis. Use the DateTime class in PHP, not time().
Be sure to read Daylight saving time and time zone best practices, and to search thoroughly for other questions on StackOverflow, as much of this has been answered already in various other questions.
I'm using FormatJS library along with Handlebars to display a list of events that occured in the past. I'm calling for an endpoint on my server's REST API which returns me the list of events in Json, with datetimes to display for each event. ATM I'm saving datetimes in the DB using GMT time zone.
So when I'm getting my Json, I'm handling datetimes like this :
{{formatRelative commentDate}}
My issue is, since the datetimes are stocked in GMT, they display also like that. For example, since I'm on a GMT+2 timezone, as soon as a new event is created and shows up on the list, I see it "happened 2 hours ago" while it should be "a few seconds ago".
So, is there a way I can handle this ? Am I making a mistake in saving datetimes in GMT in my DB, and if so, how would you handle datetimes coming from different timezones and displaying them to people in other timezones ?
Of course I could customize the formatRelative helper to play with getTimezoneOffset and get the wanted result, but I wanted to know if there is something better to do.
Thanks a lot ahead !
The key to understanding your question is what you wrote in the comments:
Getting the Json, containing datetimes in the format 2016-02-28 10:15:53 - that's UTC time
You should ensure the value in JSON is in full ISO8601 format, including the appropriate offset or Z character to indicate UTC: 2016-02-28T10:15:53Z
Without the offset, most implementations will consider the value to be represented in local time, which explains your results.
Thus, the problem is with your server-side code, not your JavaScript code. There may be a client-side workaround you could apply when the date string is parsed from JSON, but really the best solution would be to qualify it at the server.
I'm about to go insane dealing with datetime issues and the web.
I have a web server hosted in the Central Time Zone. When clients in the Eastern Time Zone try and schedule an item for a given day using my app, they pass in the value of (for example) 3/14/2015. When we pass the code back to our model, which is sent to the web api, we persist is using something like the code below.
moment.utc($("#mydatepicker").val).hour(0).minute(0).second(0)).toISOString();
This results in a string like the following:
2015-03-14T04:00:00.000Z
When the item is converted back on the server in web api, it converts to
3/13/2015 11:00:00 PM
Logic then strips off time and you can see what happens from here. Since I stripped off the time, it is now the day prior and that is the value persisted to the database.
I need to know some way to send a value from moment, into the web api preferrably as a ZonedDateTime in the client's time zone. I can then convert it to UTC for persistance in the DB.
I've seen things about using NodaTime.Serialization.JsonNet, but I am unclear on how to to use it with Moment and pass it back and forth across web api/ajax.
I need to know some way to send a value from moment, into the web api preferrably as a ZonedDateTime in the client's time zone. I can then convert it to UTC for persistance in the DB.
If that's what you want, then:
In your moment.js code, use .format() instead of .toISOString(), which will still give you an ISO8601 string, but will include the local offset instead of setting it to UTC.
In your ASP.Net code, define your values as a DateTimeOffset (or a noda OffsetDateTime) rather than a DateTime.
However, I don't think that's really what you want. When it comes to dates and times, context is super important. Here, you said you were picking a date from a date picker. When you do that - what time is being chosen by the user? In most cases, they aren't choosing a time - they're just picking a date. But since the JavaScript Date object is really a "date + time" object, it assigns midnight as a default time. Moment is no better in this regard.
Really, converting to UTC doesn't make logical sense when you are just talking about a calendar date. The string value you probably should be sending across the wire should just be a whole date, as in "2015-03-14". My guess is that is what you are starting with anyway. If not, then do moment.utc(yourvalue).format("YYYY-MM-DD") to get it. (Using UTC here is just a way to avoid local time zone issues, like midnight not existing in Brazil on the spring-forward day.)
This corresponds to the NodaTime LocalDate type in your .NET code. If you weren't using Noda Time, you would define the type as a DateTime and just ignore the time portion. In your database, if there's a date-only type available, then use it. For example, SQL Server has a date type.
I'd also encourage you to watch my Pluralsight course, Date and Time Fundamentals - which covers many of these issues.
Regarding using NodaTime.Serialization.JsonNet in WebAPI (so you can use LocalDate directly), in your WebApiConfig.cs file, wire it up like so:
config.Formatters.JsonFormatter.SerializerSettings
.ConfigureForNodaTime(DateTimeZoneProviders.Tzdb);
Then it should just work.
I would start by sending all dates and times to the server as UTC times. If you store UTC times only then you should be able to show the correct time that something is scheduled on the client side.
When you create your moment on the client side, do you run it out .toDate() first before sending it to the server side? What code are you running on the server side? Is it a .Net WebApi?
What is the best approach for dealing with DST values when your web service accepts requests from different timezones than that of your server?
My webservice accepts date strings using the ISO8601 standard (2012-02-21T05:00:00.000-05:00)
I want to account for DST but don't want the overhead of maintaining or connecting to a database to get the DST for each request which comes in from a different timezone to my server.
One approach im considering is using the servers default DST settings and then for each request that comes in convert it to the same timezone as my server is in. Then when the processing is done , convert the string back to the timezone of the client and return. The conversion of the response data could be done on the server or the client.
Any suggestions?
You could also take a look at the XDate project for handling date objects in Javascript. It's quite similar to JodaTime (in Java). Very easy to use and semantic.
XDate project
Here's what I would do. Before you submit your data/time, parse the strings into a JavaScript Date object. Then call getTime() and submit that value. getTime() returns the number of milliseconds since the UTC epoch, so in effect, it normalizes your times. Then when you return data to the user, pass in your UTC millisecond value to the constructor of a Date object and display the time as you would. By default, it'll display in the user's timezone.
I am having an issues passing a JSON containing DateTime to asp.net code-behind (c#).
If the client browser is in the same timezone as the server I have no issue, but if they are in different timezones my time is getting modified by the offset value of the two timezones.
But all my datetimes need to be the date with a time of 00:00, regardless of the time zone this datetime comes from.
Thanks
If you want the client and the server to share the same relative time like that, have the client pass back a string describing the date in some easy-to-parse format. Then your server code can parse that string as if it's local time.
Alternatively you could have everything work in UTC time.
You have to be careful with things like this of course. For example, if the client is expecting to schedule some activity to take place at the server, then the server's midnight may not be the same as the midnight at the client. The client therefore needs to make it clear that the time setting is for the server's time zone.