Parsing and Formatting ISO 8601 Time Intervals with CF

Robert explains using ColdFusion to parse and format ISO 8601 time intervals cfml

June 14, 2024 / Robert Zehnder

Yesterday when I was working on the recipe API i needed a way to parse ISO 8601 time intervals and to display it in a human friendly format. I had started down the road of using java to handle this for me by initially using java.time.Duration to parse out the data in to days, minutes, hours, etc and that worked really well.

I thought I would be clever and write a function to format the output for me by "mathing out" the hours, minutes, and seconds and out put that as a string. It got complex and unwieldy quickly. Since I was already using java to parse the duration I thought I would see if there is a way to format it as well. In CF org.apache.commons includes DurationFormatUtils that will allow us to output durations in several different formats. I decided to use formatDurationWords.

I went ahead and created a utiltiy function that accepts a string input to parse. As an example, the totalTime value of a recipe would output "1 hour and 5 minutes" from "PT65M". I was already using java.time.Duration to parse the input string, the final step was adding DurationFormatUtils to actually format the output using formatDurationWords(). I will strip off elements with leading and trailing zeros, which is the two boolean flags specified in the function. The formatDurationWords() method also expects time to be represented in millisconds, so I get the number of seconds in the duration and then multiply that by 1000.

Here is the resulting function:

  * Parse a duration and returns a string
  * @duration string to parse
  * @return string
 function durationToStr( required string duration ){
  var d         = createObject( "java", "java.time.Duration" );
  var formatter = createObject( "java", "org.apache.commons.lang3.time.DurationFormatUtils" );
  return formatter.formatDurationWords(
   d.parse( arguments.duration ).getSeconds() * 1000,

This was much cleaner than anything I would have done. I am glad I spent a few minutes researching and found a better way.