I want to be able to show the correct time for every user depending on their timezones, and also be able to store all time records in my database in UTC.
Any thoughts of the best way to do this?
I wrote a blog post on timezones with rails, you can read it here: http://jessehouse.com/blog/2013/11/15/working-with-timezones-and-ruby-on-rails/
also be sure to watch the rails cast on timezones: http://railscasts.com/episodes/106-time-zones-revised
Related
I am working on an app where the user can log his working hours after he finished his shift. The app is developed in Ruby on Rails 4.I used the scaffold method, so it generated the necessary methods for create, read, update, delete. The fields are hours_worked:number overtime:boolean and date:datetime, for now, I plan to expand it later with more functionality, with user login and some other stuf. The model is empty, I did used the rake db:migrate method. Now I know that you can use the count method, as is shown on the official site for active record. I don't have the idea how to get the total number of hours worked and show it on the index page. Consider that I just started learning Rails. Any suggestions?
Sounds like this is best used with the Timers gem.
https://github.com/celluloid/timers
In your Sessions#new method, you'd want to initialize a variable to keep track of the current time. And then every so often, you'd use one of the methods in the gem to update the current time. You could then subtract the difference.
This is hard to answer without any info on how you are actually logging the info, or seeing any of your code. However if you are just looking for general suggestions you could just save start and stop timestamps and compare them. Or ask the user to input time worked. There are probably a thousand different ways to do this. Please be more specific on what exactly you need help with.
I am working on rails 4 application. I want to show the time for comment I created. If I open the site in india then time should be shown in IST (according to indian standard) and If I am in USA so for the same comment that i made in india time should be shown according to USA time zone.
What do I need to do in my config file for development and production?
Do I need to change anything in database?
Please help me.
Rails always saves times in UTC (universal time), and the server has a setting which tells it which timezone it (the server) is running in.
To show different times to the client, Rails (which runs on the server) will need to know which time zone the client is in. This isn't in a standard request header so you will need to get them to submit the information somehow. Once you know their timezone you can ensure that you always show times to the user using their timezone - there are helpers for this.
Getting their timezone can be done explicitly, eg by giving them a timezone dropdown in their "My Account" page, and then saving that in their user record, and/or by making it more upfront and forcing them to choose one in a popup, if you don't know it.
Or, you can do it for them using Javascript, passing it through in a cookie. See this article for an example of how to do it.
http://thisbythem.com/blog/clientside-timezone-detection/
Well one solution can be to store the time zone of the user in the database, write a filter
around_action in your ApplicationController which would set the Time.zone to the time_zone from the database field.
You might want to look at Time.zone and TimeZone in the rails api
Here is a railscast , you can figure it out from the comments and the github link.
I've spent quite a bit of time on stackoverflow and the internet trying to determine what has been done in my situation. I am building a
centralized line of business website that could span multiple timezones. Based on some valuable information here I have a plan in place to handle this.
Timezone will be a part of a user profile
All Dates will be stored in UTC
EF sets DateTimeKind to UTC on retrieval from database
Is it possible to prevent EntityFramework 4 from overwriting customized properties?
Create some html helpers for DatePickers and DateDisplays to convert UTC time to local time (based off user timezone)
Use Model Binding to convert back to UTC on form posts.
Timezone Strategy
Now to the issue I don't know how to solve. Kendo UI uses JSON to pass information back and forth and as far as I can tell the JSON.net serializer cannot serialize a date to a specific time zone. I can serialize the date as UTC or have JSON.net automatically convert it to local time using the DateTimeZoneHandling setting but that would be local time on the server. From looking at the JSON.net code, I'm not sure I could even write a converter to do what I wanted. So far now if I send the date as UTC through JSON.net and Kendo automatically converts the time to the browser's local timezone.
Assuming User Profile timezone = Browser Timezone seems a little scary for me and I wanted to see what stackoverflow suggests I do. Thank you in advance.
Technology
ASP.net MVC 5
Entity Framework 6
Telerik Kendo UI Controls
JSON.net
Unfortunately I don't know many of the tools you are using, but I know how I would handle timezones.
I would use UTC everywhere, except when displaying times (or rather: datetimes) and in user input.
I would let the browser's JavaScript do the conversion in output, using the browser's timezone. In input, the conversion can be done either client side or server side. In the latter case the timezone must be part of the information sent from the browser to the server. The UTC timezone on the servers should be set at a level as low as possible, and, if possible, in all components (OS, web server, DB...).
A user's preferred timezone is nonetheless useful for all cases where the timezone is not known (e.g., in email communications - but remember to always have the timezone in time formats).
There are times (no pun intended...) when the above is not easy or does not apply. E.g., a schedule (calendar), to which the user attaches the timezone they have in their head, not necessarily the browser's one. Another case is when the user's timezone has to be known for some computation that can not easily be done on the browser - in this case the server will have to get the timezone from the browser first. But most of the time (still no pun intented...) you can happily do without timezones (with UTC) except immediately before showing something to the user or immediately after getting something from the user.
Regarding your last paragraph: you will very soon run into trouble if you assume "user profile timezone = browser timezone".
Some last words of advice:
"Timezone" is an ambiguous term. It may refer to a fixed offset from UTC (like UTC+1), or to the rules for calculating this offset for any instant in a given area (like the timezone of Rome, Italy). Always use the second meaning (e.g., don't use the current offset for a date in the future or past, but correctly convert datetimes back and forth), and remember that both can change during a user's session.
Be careful not to handle "pure" dates as the midnight of the same day (and not as noon either - people in Samoa will thank you), because then the date can change when the timezone changes. In other words, don't attach time information to pure dates.
P.S.: By following a link of yours, I was happy to find that I totally agree with the closing remark of this answer (by someone with more SO reputation than me)
You certainly can pass UTC to the browser and let it convert, but you have to be aware of the potential for inaccuracies. You also can convert server-side and pass a DateTimeOffset in your JSON, but you may need to render it yourself, using something like moment.js.
In the end, what you should do is entirely up to you. Many use cases are similar, but there are plenty of acceptable different paths depending on your exact needs.
Your question is very broad the way you have asked it. What parts are you most concerned with? Kendo? EF? JavaScript? Client-side time zone conversion? Formatting? Could you refine it or provide some context to the type of things your date/time values are representing? Otherwise, you may get some useful tidbits, but it will be hard to provide a definitive answer.
(Oh, and you might be interested in this.)
I was finally able to find this answer here https://stackoverflow.com/a/11968692/3412859 that will allow me to write my own JSONconverter and convert to a specific time zone before it is serialized. I now have all of the dates being converted on the server side based on the timezone setting in the user profile.
I had this problem , too.
It works for me.
I translated the time format to
Start=2016-4-9T8:30:00.000Z
End=2016-4-9T13:30:00.000Z
in background or database.
By doing this,local time zone is useful.
In my rails application,After login a user has to create a timesheet entry.The time of creation of the entry is currently my server time.Whereas i want it to be the time of the timezone from where the entry is made i.e if entry is made from any other country.I'm using rails 3 and after searching the web also exact solution cannot be achieved.
Thanx
You can't automatically determine the user's timezone, but you can allow them to choose their own timezone. Then you can set Time.zone = ActiveSupport::TimeZone(offset) before calling update and everything should work correctly. You could also save each user's preference for time zone in your user model.
I'm not sure if it's possible to do this in Rails as the issue is getting the physical location of a user.
It may be worth using JavaScript to populate a (hidden?) field with the current time, which should be taken from user's local machine. You could then explicitly set the created_at field to be this value.
Intrigued to know if Rails can get around this somehow...
If you want, take a look to this question : transform time into local time in Ruby on Rails
And : http://www.wetware.co.nz/blog/2009/07/rails-date-formats-strftime/
Maybe it can helps you.
I'm working on a Rails application that's kind of like a blog. Users create Entries. I'm trying to work out how to handle time storage and display. I've read this writeup about Rails timezone support.
It's great but it doesn't cover what my app needs to do. It only looks at cases where you want to convert stored time to the current logged in user's time zone. In contrast, the effect I want is...
A user creates an entry in California at 10:00 a.m.
A couple years later he moves to New York and then at some point looks at his old entry. The "created" date should say "10:00 a.m." He doesn't care about time zones. He just wants to know what time of day he felt like it was when he wrote the entry.
If he then edits the Entry in New York the displayed "modified" date is, again, his subjective time of day when he made the edit. (Let's assume he went to "preferences" and changed his time zone setting when he moved.)
Also, for the sake of thoroughness, the app should be able to report the "real" absolute time when an Entry was created or updated.
(Note -- my imaginary user is a guy, but for women it should work roughly the same way.)
The way I'm thinking of implementing it is...
Have the attributes User#time_zone, Entry#created_at_utc, and Entry#updated_at_utc in addition to the standard created_at and updated_at.
The user selects their time zone from a menu when they sign up. (They can change it later if they want.)
The app uses User#time_zone to store created_at and updated_at in the user's subjective local time. If it's 10:00 a.m. for them, the app writes "10:00 a.m." to the DB.
The app also saves the current UTC time in the aforementioned _utc fields to deal with the last requirement above.
Is that a good way to do it? Is there a better way?
The two roads you can take are:
Store a timezone (UTC) in the user account as well as in every post - update the post's timezone along with the updated_at field whenever the user changes the post (if he or she has changed timezones).
Store the timezone only in the user account. When the user changes timezones, update every post that belongs to the user and add/subtract to the created_at/updated_at dates.
The first option seems like the cleanest option to take. For this you would only have to create a new method in your post record:
def locational_updated_at
updated_at + timezone.seconds
end
Where timezone is an integer containing the seconds since UTC.
If you can, you should avoid storing two different sets of timestamps, and you should avoid storing any non-UTC dates. Both of these things will lead to confusion. I'm not completely sure I understand what you're doing (though I like your idea of subjective time), but wouldn't it be enough to just attach a time zone to every post, and always use that zone to display the times? It would default to the time zone set in the author's account, so he could change it when he moved cross-country without affecting previous posts.
I think that's all you need--to attach a time zone to every post. Is that sufficient? Or am I missing some part of this?