Working with Dates and Time Zones in Groovy
There are times when we need to do some date operations or parse dates or format dates to a desired format. Groovy has extensions that allows us to work with dates more easily. We’ll use a project created using the “Website_editorial” blueprint, and add a script that will run when we preview an article page.
First, let’s set the time zone in Crafter Engine. From the Sidebar, click on 
, then click on Configuration. Select Engine Project Configuration from the dropdown list, then enter the following into the configuration:
<?xml version="1.0" encoding="UTF-8"?>
<site>
<timeZone>America/Los_Angeles</timeZone>
</site>
We’ll now create a controller by opening the Sidebar, then navigate to scripts -> pages, right click on pages, and select Create Controller, which we will then name article.groovy, which would make it execute before the article page is loaded. We’re now ready to show some examples of working with dates and times in Groovy. We’ll be performing operations on the contentModel variable date_dt, which is the date created of the article. For more information on variables available in groovy scripts, see Groovy/Java API
Formatting Dates
To format the date to a certain format pattern, which we then pass to a templateModel variable so we can use it in the Freemarker template, do the following:
def formattedDate = aDate.format("EEEE, MMMM dd, yyyy, hh:mm a '('zzz')'")
templateModel.formattedDate = formattedDate
Which will output this:
Tuesday, December 27, 2021, 09:00 PM (PST)
To format the date for a certain format pattern and time zone, do the following:
def formattedDate = aDate.format("EEEE, MMMM dd, yyyy, hh:mm a '('zzz')'", TimeZone.getTimeZone("EST5EDT"))
Which will output this:
Wednesday, December 28, 2021, 12:00 AM (EST)
Let’s show another example of formatting the date for a certain format pattern and using the time zone setup in the Engine Project Configuration file, by using the variable siteConfig:
def formattedDate = aDate.format("EEE, MMMM dd, yyyy, hh:mm a '('zzz')'", TimeZone.getTimeZone(siteConfig.getString("timeZone")))
Which will output this:
Tue, December 27, 2021, 09:00 PM (PST)
For more information on format patterns, see https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/text/SimpleDateFormat.html
For more information on time zone offset, see https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/TimeZone.html
Parsing Dates
To convert a date string into a date object (so you can perform date arithmetic, get year, month, date values separately), do the following:
def nowString = "2022-Oct-26 11:45:23 PM"
def nowDate = Date.parse("yyyy-MMM-dd hh:mm:ss a", nowString)
Which will output this for nowDate:
Thu Oct 26 23:45:23 PDT 2022
Date Arithmetic Operations
We’ll use the same example above to perform arithmetic operations on the date object. There are two ways to perform the arithmetic operations on the date objects, using the plus and minus methods, and using the + and - operators.
Say, we want to find the date object 10 days after the date in our example above. We will use the plus method and the + operator to increment the date by 10 days:
def nowString = "2022-Oct-26 11:45:23 PM"
def nowDate = Date.parse("yyyy-MMM-dd hh:mm:ss a", nowString)
def addDate = nowDate.plus(10) // date arithmetic using the "plus" method
def addDate2 = nowDate + 10 // date arithmetic using the "+" operator
Both addDate and addDate2, will output:
Sun Nov 05 23:45:23 PST 2022
Now, if we want to find out the date object 30 days before the date in our example, we can use either the minus method or the - operator to decrement the date:
def subDate = nowDate.minus(30) // date arithmetic using the "minus" method
def subDate2 = nowDate - 30 // date arithmetic using the "-" operator
Both subDate and subDate2 will output:
Tue Sep 26 23:45:23 PDT 2022
For more information on Groovy Date methods, see http://docs.groovy-lang.org/latest/html/groovy-jdk/java/util/Date.html