rfc-date-to-iso-date.xsl

<?xml version="1.0" encoding="UTF-8" ?>
<!--
  Name: RSS feed date format to Symphony date format
  Version: 1.0
  Author: Brian Zerangue <brian.zerangue@gmail.com>
  URL: http://symphony21.com/downloads/xslt/file/20457/
 
  Description:
  Convert RSS feed date format to Symphony date format
  Convert RFC 2822 timestamp format to ISO date format (Symphony CMS date format)
  RFC 2822 format: Sun, 7 Jan 2007 12:00:00 -0600
  ISO 8601 format: 2007-01-07T18:00:00

  Usage:
  The named template "format-from-rfc-to-iso" takes 2 parameters, 1 required and 1 optional:
  1. rfc-date - [required] a valid rfc 2822/rss date
  2. with-time - [optional] 'yes' (default) or 'no'.  in addition to the date, output the time in UTC

  Notes:
  This has not been tested with RFC dates which append a timezone identifier rather than a 4-digit offset.
-->

<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
				xmlns:date="http://exslt.org/dates-and-times"
				extension-element-prefixes="date">

	<xsl:template name="format-from-rfc-to-iso">
		<xsl:param name="rfc-date"/>
		<xsl:param name="with-time" select="'yes'" />

		<xsl:param name="day-with-zero" select="format-number(substring(substring($rfc-date,6,11),1,2),'00')"/>
		
		<xsl:param name="month-with-zero">
			<xsl:if test="contains($rfc-date,'Jan')">01</xsl:if>
			<xsl:if test="contains($rfc-date,'Feb')">02</xsl:if>
			<xsl:if test="contains($rfc-date,'Mar')">03</xsl:if>
			<xsl:if test="contains($rfc-date,'Apr')">04</xsl:if>
			<xsl:if test="contains($rfc-date,'May')">05</xsl:if>
			<xsl:if test="contains($rfc-date,'Jun')">06</xsl:if>
			<xsl:if test="contains($rfc-date,'Jul')">07</xsl:if>
			<xsl:if test="contains($rfc-date,'Aug')">08</xsl:if>
			<xsl:if test="contains($rfc-date,'Sep')">09</xsl:if>
			<xsl:if test="contains($rfc-date,'Oct')">10</xsl:if>
			<xsl:if test="contains($rfc-date,'Nov')">11</xsl:if>
			<xsl:if test="contains($rfc-date,'Dec')">12</xsl:if>
		</xsl:param>
		<xsl:param name="year-full" select="format-number(substring(substring($rfc-date,6,11),7,5),'####')"/>
		<xsl:param name="time" select="substring-before(substring-after($rfc-date, concat($year-full,' ')), ' ')" />
		<xsl:param name="offset" select="substring-after($rfc-date, concat($time, ' '))" /> <!-- grab the timezone offset -->
		<xsl:param name="duration" select="concat(translate(translate(substring($offset,1,1),'-',''),'+','-'),'PT',substring($offset,2,2),'H',substring($offset,4,2),'M')" /> <!-- convert the timezone offset to a usable xml duration for date:add, http://www.w3.org/TR/xmlschema-2/#duration -->
		<xsl:param name="iso-date" select="concat($year-full,'-',$month-with-zero,'-',$day-with-zero)" />	

		<xsl:param name="rfc-date-to-iso">
			<xsl:if test="$with-time = 'yes'">
				<xsl:value-of select="substring-before(date:add(concat($iso-date,'T',$time), $duration), 'Z')" /> <!-- add the timezone difference to the date+time, drop the 'Z' -->
			</xsl:if>
			<xsl:if test="not($with-time = 'yes')">
				<xsl:value-of select="$iso-date" />
			</xsl:if>
		</xsl:param>

		<xsl:value-of select="$rfc-date-to-iso" />
	</xsl:template>
</xsl:stylesheet>