According to Yahoo, my account is using MySQL 4.1.14, and PHP 4. Yeah, I know I am a bit behind. I noticed some funny things started going on with my code a while back, around dates. But I thought time zone setting did not come into play until PHP 5.
Anyway, I am pulling dates from a database using UNIX_TIMESTAMP, and it gives me a timestamp like 1436745600 for a date 2015-07-13 stored in my database. This looks correct to me. But then my code simply does a date('M-j','variable storing that number'), and it gives me 'July-12'. Why is this?
I know I am PST, and the server is UTC, but on version 4, how would PHP know that? And even if it did, we are both on the same day for most of a 24 hour cycle. As I started writing this, we were on the same day, and still the problem occurred. As I finish, we are on different days, and the result is the same. Something else going on here?
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First of all I am a beginner, and I don't want anybody to write code for me. I would just like a bit of a hint from a more experienced developer.
I have a video site, what loads videos from another website with XML and saves info about the videos in the database. What I would like to do is that if a week is passed, automatically run the insert query.
I never did this before and never worked with time functions like this. So please could someone show his plan how he would do it? So no code, just explain the process.
I'd recommend setting up a cron: http://en.wikipedia.org/wiki/Cron
I dont think this is a coding-related problem. Tasking can be achieved by using cron.
Cron is a task scheduler, which when its available for your hosting, can be accessed at the hosting control panel. What is your host ?
You could use Cronjobs.
What do you want to do with the data in the week in between? I hope you're not hoping to keep a process running for a week and then execute the insert.
You could do something like load the XML and save it in the database, setting an active column to 0. You save the timestamp at the moment the insert is executed.
Meanwhile, using cron, you let a script run every X minutes or hours, checking the database for items that have been inactive for a week, and then updating them to become active.
You can use the time() function. It returns the number of seconds since January, 1st, 1970.
Then, for example, you take the time at t = 0.
When time() - t > a week (= 3600 * 24 * 7 seconds), you know a week has passed by.
So I am really stumped because I have basic ideas but I am looking for some of your expertise.
What I am trying to do: I want to basically write an app using Twilio which you dont really need to know about because that is another issue. What that app does is call on a php file in my web host and "triggers the php code"
What I need help with here is how can I keep record in php of the calendar of the week for my computer. What I mean by that is if someone like an admin has a specific code that I have written for them, and that code runs automatically all week, but a specific week they dont want that code to run, instead they want a different code to run that week. How can I use php to find when a week has ended or keep track of the week using that calendar in bottom right of your computer screen so that my program will know after an admin wants a different code run from the usual code that the week is over no need to run that admin irregular code any more go back to your usual automated running code.
If you still dont know what I am talking. I will try to explain more. Think of 2 separate codes. One Custom and the other automated. The automated runs all the time automatically. But one day the admin chooses for that week he doesnt want to follow the regular shcedule of running the automated code as usual, instead for that week he would like to run the custom code and after the week is over go back to running the automated code as usual.
I hope that makes it more clear. I know that in PHP gives the date. But I really need expert opinion on how to do this.
Generally for something like this, I'd generate a "nextrun_datetime" for each and every script/user combination. By default it would have a repeat interval, in your case, 7 days.
If a user doesn't want to run it this week, they can "push" it out N days and the normal update interval would apply afterwards. To get the one-time shot, I'd allow an update interval of 0 or -1 to denote that.
With this sort of thing, whenever a script is updated (or saved, run, rescheduled), you can calculate the next date if there is one. From there, it's a relatively simple cron job that should check the last N minutes for any scripts to be run.
Unless your client machines are running on a completely different calendar than the server, why bother with wondering what the client's date is? Unless the client and server are in different time zones, the client date is going to be the same as the server date, except for a few hours around midnight.
As well, why depend on the client to trigger the server-side code? If this is a regularly occuring thing, use cron or whatever's available on the server to run the code automatically. If an admin wants to override WHICH code gets run, then you can provide an interface to change what's executed. Click a button on a site and a flag is set somewhere that tells the timed job to run script B instead of script A.
I've done something similar. Based on the day (e.g. monday, sunday) I would do something different in php.
this is how I did it:
$today = date('w');
if ($today== 0){
//its sunday
exec('rmdir C:\myApp\oldLogs');
}
else{
echo '1 -> monday, 2-> tuesday etc...'
}
you can also make a date from a string for example
$date = strtotime("8 days ago 14:00");
/*
or "Monday next week", "+1 week 2 days 4 hours 2 seconds","yesterday noon","10 September 2000" etc...
*/
I have a table of 'notifications' which may or may not be sent in any 24 hour period. Each notification has it's own timezone offset from GMT, so I have a column for offset which will be +/- in seconds.
I need to create a PHP script which will regularly (via cron) check the database for sent notifications, and then reset them to unsent if their time has passed 00:00 for that day. I'm really struggling with the best way to do this - is there a simple calculation I can make?
I was thinking of something around getting the UNIX time for the server's midnight using mktime() [my server is in GMT], and working it out with the offset in seconds, but every way I think of seems wrong.
Something like:
if(!mktime()-$notifcationTimezone > $serverMidnight){}
I'm not saying this doesn't work, but I don't think it will work when the server elapses into another day. It just confuses me, and I have no faith in it.
Isnt this just a simple comparison with strtotime and you dont even need to add up the offset. You can use the date function to set a specific time you want to pass to the strtotime which you want to use to compaire against.
To give us a better idea show us a real example from you database and what the cron looks like right now.
I'm not totaly sure what you are trying to pull of here but, what you might wanna think about is do you really want to reset anything, is it needed? You could fill in at what date your notification got send. If it does not match the date of today you want to resend it again?
I have some dates/events in a database, and I'd like to pull them out ordered by month (year doesn't matter) - right now all the timestamps are in unix in a column named eventDate. How can make that query?
SELECT * FROM calendar ORDER BY eventDate
Obviously that sorts them, but I want to make sure all events across all years are grouped by month - then obviously need to arrange them January, February, March, etc.
Any advice?
Thanks!
You could use FROM_UNIXTIME() function + MONTH() function.
SELECT MONTH(FROM_UNIXTIME(0));
-- 12
But there's no reason to store a unix timestamp over a real timestamp (YYYY-MM-DD HH:II:SS). RDBMS have functions to manipulate dates and if you really need the unix timestamp (I never do, TBH), you can use the UNIX_TIMESTAMP function.
There are plenty of extremely good reasons for using unix time. Good database design hugely impacts how expensive it is to run databases and website, especially successful busy ones.
The best case I know of is..
a really busy server(s) and where time data is required to be stored but the time data is actually accessed rarely compared to the number of reads and writes actually going on in the db. It takes cpu resources to do all the manipulation of that time data, So don't unless you absolutely have to.
A real life example is my own. We needed 4 front end web servers and were going to be adding more. they were old too and needed updating. looking at 6 replacement servers that would be needed it was going to cost us a bundle. decided to look about what we were doing. We now have 2 front end servers instead of 4 or 6. what it took? optimizing the database structure and queries and the code that inserted and read data from them.
One example that took your exact consideration in mind... changed 1 line of php code, changed the time column to unix instead of yyyy-dd-mm hh:mm:ss, added an index to the time column and that one operation went from 0.08 seconds to 0.00031 seconds start to finish.
The multifold impact on cpu resources was huge. the next queued up operations executed faster... etc.
That is why people have jobs as database designers... it really is important.
of course if your website is slow and not busy.. probably no one will notice.
But if you are successfull, it WILL matter.
If you've got a busy site and your servers get sluggish... look at things like this. You might not need a new box or more memmory, you just might need to clean up code and optimize the db.
Timestamps, their form and how they are used and stored DO MATTER.
this might be stupid question, but ill ask anyway.
do i really need to implement gmt on site to get proper timestamp on a post? well im building a site like twitter. my feeds are working fine and showing me the time i need, like it shows "posted 11 minutes, posted yesterday, posted 5 days ago.. " just like this site, so i was thinking it should work for everyone properly, what you think? or do you think i need to implement gmt on it and do you recommand or have any article on it for implementing it proper way?
sorry if this sound stupid :O
In the long term, it is best to store time stamps always in GMT/UTC, no matter how the user interface is rendered. This has two advantages:
when changing the UI at some point, you won't need to touch the data
it gives a clear design guideline (in terms of a clear right/wrong decision): any specific function dealing with time can be independently reviewed wrt. processing timestamps in UTC
As for specific programming guidelines: these depend very much on the functionality you want to execute. Most of the time, you need either from-utc or to-utc operations.
It's a good point, but consider the case when 1 day ago suggests "yesterday", and it's currently 1:05am for some user. I suppose if you're using days = hours % 24 rather than days = datediff(then, now).days, then it would work fine.
I think the issue is: how accurate does your site need to be? If it's for medical readings, so someone can know when their medication is due, then yes, you want to account for timezones properly, and give accurate times rather than just "x ago". If it's just for "joe said hi two days ago", though, then it's not a big deal.
When you're talking about time periods like hours, minutes and seconds, then that's not even anything to do with timezones. Look at the timestamp of when it was created, and look at the timestamp now. Do some subtraction and voila!
The only time it's slightly strange is when you are in the range of a couple of days. Does yesterday mean "some time in the 24 hours prior to the last midnight", or does it mean "over 24 hours ago"? In any case, if the only level of granularity you are providing is "days", then once it's gone past about 2 days, then it doesn't really matter.
One nice way to avoid confusion is the same method used here on SO: put the readable, friendly date on the screen ("yesterday"), but put the exact time (in GMT or in the user's TZ) as a tooltip.