image - Removing the last characters in an XSLT string

Question

In my CMS it is possible to create a new article, and choose an image to be shown on that article. When an image is chosen, a thumbnail of the image will automatically be created as well.

If the uploaded image is called image.jpg, then the corresponding thumbnail will automatically be named image_thumbnail.jpg.

I would now like to use the thumbnail image, everywhere on the website where the article is mentioned, except in the article itself (where the original big image should be shown).

But how can I do that?

I imagine if I could get the original name of the image, and then split it up before the suffix (.jpg, .png, .jpeg etc.) and hardcode _thumbnail after the name, then that would be sufficient.

In other words, I want to take the complete filename, and cut it into two parts, so that I can insert the string _thumbnail between the two parts.

Maybe that would work, but what if an image called image.2horses.jpg (a file with more than one dot in the filename) is uploaded? A naive cut before the '.' wouldn't work here.

Is there a way to get around this? Perhaps by cutting the filename up before the last 4 (.jpg, .png) or 5 (.jpeg) characters?

Answer 1

Off the top of my head:

<xsl:template name="substring-before-last">
  <xsl:param name="string1" select="''" />
  <xsl:param name="string2" select="''" />

  <xsl:if test="$string1 != '' and $string2 != ''">
    <xsl:variable name="head" select="substring-before($string1, $string2)" />
    <xsl:variable name="tail" select="substring-after($string1, $string2)" />
    <xsl:value-of select="$head" />
    <xsl:if test="contains($tail, $string2)">
      <xsl:value-of select="$string2" />
      <xsl:call-template name="substring-before-last">
        <xsl:with-param name="string1" select="$tail" />
        <xsl:with-param name="string2" select="$string2" />
      </xsl:call-template>
    </xsl:if>
  </xsl:if>
</xsl:template>

Called as:

<xsl:template match="/">

  <xsl:variable name="filename" select="'image.2horses.jpg'" />

  <xsl:variable name="basename">
    <xsl:call-template name="substring-before-last">
      <xsl:with-param name="string1" select="$filename" />
      <xsl:with-param name="string2" select="'.'" />
    </xsl:call-template>
  </xsl:variable>

  <xsl:value-of select="$basename" />

</xsl:template>

Yields:

image.2horses