Finding the difference between two dateTimes in XSLT

Question

I have an XML file which includes some dates with start and end points, like shown as follows:

<start time="2016-02-21T00:59:06+02:00"/>
.....
.....
<end time="2016-02-22T02:24:38+02:00"/>

Question:

How to calculate the difference between two time attributes?

Answer 1

I am getting the error: ... xsl:version: only 1.0 features are supported

Here's a purely XSLT 1.0 solution:

<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>

<xsl:template match="event">
    <xsl:variable name="start">
        <xsl:call-template name="dateTime-to-seconds">
            <xsl:with-param name="dateTime" select="start/@time" />
        </xsl:call-template>
    </xsl:variable> 
    
    <xsl:variable name="end">
        <xsl:call-template name="dateTime-to-seconds">
            <xsl:with-param name="dateTime" select="end/@time" />
        </xsl:call-template>
    </xsl:variable>
    
    <xsl:variable name="duration" select="$end - $start" />
    <xsl:variable name="d" select="floor($duration div 86400)"/>
    <xsl:variable name="t" select="$duration mod 86400"/>
    <xsl:variable name="h" select="floor($t div 3600)"/>
    <xsl:variable name="r" select="$t mod 3600"/>
    <xsl:variable name="m" select="floor($r div 60)"/>
    <xsl:variable name="s" select="$r mod 60"/>
    
    <xsl:copy>
        <xsl:copy-of select="name"/>
        <duration>
            <xsl:value-of select="$d"/>
            <xsl:text> days, </xsl:text>
            <xsl:value-of select="$h"/>
            <xsl:text> hours, </xsl:text>
            <xsl:value-of select="$m"/>
            <xsl:text> minutes and </xsl:text>
            <xsl:value-of select="$s"/>
            <xsl:text> seconds</xsl:text>
        </duration>
    </xsl:copy>
</xsl:template>

<xsl:template name="dateTime-to-seconds">
    <xsl:param name="dateTime"/>

    <xsl:variable name="date" select="substring-before($dateTime, 'T')" />
    <xsl:variable name="time" select="substring-after($dateTime, 'T')" />

    <xsl:variable name="local-time" select="substring($time, 1, string-length($time) - 6)" />
    <xsl:variable name="offset" select="substring-after($time, $local-time)" />

    <xsl:variable name="year" select="substring($date, 1, 4)" />
    <xsl:variable name="month" select="substring($date, 6, 2)" />
    <xsl:variable name="day" select="substring($date, 9, 2)" />

    <xsl:variable name="hour" select="substring($local-time, 1, 2)" />
    <xsl:variable name="minute" select="substring($local-time, 4, 2)" />
    <xsl:variable name="second" select="substring($local-time, 7)" />

    <xsl:variable name="offset-sign" select="1 - 2 * starts-with($offset, '-')" />
    <xsl:variable name="offset-hour" select="substring($offset, 2, 2) * $offset-sign" />
    <xsl:variable name="offset-minute" select="substring($offset, 5, 2) * $offset-sign" />

    <xsl:variable name="a" select="floor((14 - $month) div 12)"/>
    <xsl:variable name="y" select="$year + 4800 - $a"/>
    <xsl:variable name="m" select="$month + 12*$a - 3"/>    
    <xsl:variable name="jd" select="$day + floor((153*$m + 2) div 5) + 365*$y + floor($y div 4) - floor($y div 100) + floor($y div 400) - 32045" />

    <xsl:value-of select="86400*$jd + 3600*$hour + 60*$minute + $second - 3600*$offset-hour - 60*$offset-minute" />
</xsl:template> 

</xsl:stylesheet>

Demo: http://xsltfiddle.liberty-development.net/aiyndK

Answer 2

Your dates are in ISO format so in XSLT 2.0 you can do

xs:dateTime(end/@time) - xs:dateTime(start/@time)

The result is an xs:dayTimeDuration, which you can convert to seconds (for example) by doing

(xs:dateTime(end/@time) - xs:dateTime(start/@time)) div xs:dayTimeDuration('PT1S')