Part of a PHP project I’m working contains a list of sites/buildings. For each site/building we monitor some data, for example its energy usage. We decided that we wanted to generate a daily/weekly/monthly reports of the data, by aggregating the datapoints. As our sites/buildings are spread across the globe – and thus timezones – we […]
Tag Archives: datetime
Why Denmark Is .17 Seconds Behind The World
Measuring time is a complicated thing. Computers, banks, and stock markets in Denmark all use UTC, the international standard: but according to the law, they shouldn’t. 🤓 Also see Falsehoods programmers believe about time and time zones
How to Perform Calendar Calculations in Your Head
In case you want to impress your family over Christmas’/New Year’s Dinner: A so-called calendrical savant (or calendar savant) is someone who despite their intellectual disability (typically autism) can name the day of the week of a given date, or visa versa in a few seconds or even a tenth of a second (Kennedy & […]
spatie/test-time – A PHP package to control the flow of time
Freek has created spatie/test-time, a package to easily freeze/rewind/advance time in PHP. Imagine you’re building that your app can notify your user, but you don’t want to send more than one notification in a timeframe of five seconds. How are you going to test the time aspect? Do you have to create a test that […]
Symfony Form Validation: Validating a date range
One of the (Symfony based) PHP projects I’m working on contains a form which allows the user to generate video clips from CCTV footage. To do this the user can enter a start and stop DateTime. For this to work the submitted input data is then checked: both start and stop must be dates, and […]
php-timecop – A PHP extension providing “time travel” capabilities
Now this looks handy, especially when you’re writing/testing code that’s dependent on the system’s time: php-timecop is a PHP extension providing “time travel” and “time freezing” capabilities Freeze time to a specific point. Travel back to a specific point in time, but allow time to continue moving forward from there. Scale time by a given […]
Carbon – A simple PHP API extension for DateTime.
$carbon = new Carbon(‘first day of next week’); if ($carbon->isWeekend()) { echo ‘Party!’; } echo $carbon->addYear()->diffForHumans(); // ‘in 1 year’ Carbon is just a class which is designed to be used instead of DateTime. Due to extending DateTime, all DateTime methods are available to users of Carbon. Additionally, it implements a __toString method, allowing users […]
Falsehoods programmers believe about time and time zones
Every day has 24 hours Every day without DST changes is 86400 (60 * 60 * 24) seconds long Every day in UTC is 86400 (60 * 60 * 24) seconds long Week one of a year starts in January every year If I know what time zone someone is in and they just tell […]