random quotes images

tesuji 95 posts 139 karma points

Mar 01, 2010 @ 23:32

Random quotes, images

My client wants to include random images and quotes on a web page. I need to pick randomly from a collection of existing images and quotes. (It doesn't have to be exactly random, but something similar - to be different with a new page load).

Does Umbraco do this already, or are there sample code or packages I can use?

I think .NET has an ad rotator control. Would it be easiest to just put this in a user control?

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Jesper Hauge 298 posts 487 karma points c-trib

Mar 01, 2010 @ 23:57

If you're doing this from a usercontrol - you can create an extension method to the umbraco.presentation.nodeFactory.Node class, that selects a random child node like this:

using System;
using umbraco.presentation.nodeFactory;

namespace My.Umbraco.Extensions
{
  public static class UmbracoExt
  {
    /// <summary>
    /// Returns a random childnode from provided node
    /// </summary>
    /// <param name="node">node to look in</param>
    /// <returns>Node</returns>
    public static Node GetRandomChild(this Node node)
    {
      if (node.Children.Count == 0)
        return null;
      if (node.Children.Count == 1)
        return node.Children[0];
      var rnd = new Random(DateTime.Now.Millisecond);
      return node.Children[rnd.Next(0, node.Children.Count)];
    }
  }
}

This enables getting a random child node and its data like this in the codebehind:

using System;
using System.Web;
using System.Web.UI;
using My.Umbraco.Extensions;
using umbraco;
using umbraco.BusinessLogic;
using umbraco.presentation.nodeFactory;

namespace petersen_gruppen.dk.usercontrols
{
    public partial class TopPic : System.Web.UI.UserControl
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            var currentNode = Node.GetCurrent();
            var picNode = currentNode.GetRandomChild()
            yourImg.Src = picNode.GetProperty("umbracoFile").Value;
            quoteLiteral.Text = picNode.GetProperty("quoteText").Value;
        }
    }
}

This code assumes you that the docs with quotes/images is childnodes to the current page, if not you can select the currentNode from its id. It also assumes you have a series of nodes of a doctype that has an upload field named "umbracoFile" for the image and a text property named "quoteText" for the text.

Hope this will give you an idea.

Regards
Jesper Hauge

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Douglas Robar 3570 posts 4711 karma points MVP ∞ admin c-trib

Mar 02, 2010 @ 00:13

This can also be done in XSLT.

Here's an example that uses ImageGen to make a thumbnail of a random image. The hard-coded variables could certainly be passed in as macro variables instead.

In my example, I was making a portfolio. I pre-loaded the full-size portfolio images into the Media section. I then added a Media Picker property to my portfolio docType for the associated image. I put all my portfolio pages below a single content page (the $folder varaiable in my code). Then the macro could simply select a random node from below the $folder page and display the thumbnail using ImageGen to resize it to any size I wanted.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xsl:Stylesheet [ <!ENTITY nbsp "&#x00A0;"> ]>
<xsl:stylesheet
    version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:msxml="urn:schemas-microsoft-com:xslt"
    xmlns:umbraco.library="urn:umbraco.library"
    xmlns:Exslt.ExsltMath="urn:Exslt.ExsltMath"
    exclude-result-prefixes="msxml umbraco.library Exslt.ExsltMath">


<xsl:output method="xml" omit-xml-declaration="yes"/>

<xsl:param name="currentPage"/>
<xsl:variable name="folder" select="1158"/>
<xsl:variable name="thumbnailHeight" select="60"/>

<!-- ============================================================= -->

<xsl:template match="/">

   <xsl:variable name="imageID">
       <xsl:call-template name="GetRandomNode"/>
   </xsl:variable>

   <img alt="Portfolio">
       <xsl:attribute name="src">
          <xsl:text>/umbraco/imagegen.aspx?image=</xsl:text><xsl:value-of select="umbraco.library:GetMedia($imageID, 0)/data [@alias='umbracoFile']"/><xsl:text>&amp;height=</xsl:text><xsl:value-of select="$thumbnailHeight"/>
        </xsl:attribute>
    </img>
</xsl:template>

<!-- ============================================================= -->

<xsl:template name="GetRandomNode">
  <xsl:variable name="numNodes" select="count(umbraco.library:GetXmlNodeById($folder)/node)"/>
    <xsl:variable name="random" select="floor(Exslt.ExsltMath:random() * $numNodes) + 1"/>

    <xsl:choose>
        <xsl:when test="umbraco.library:GetXmlNodeById($folder)/node [position() = $random] [string(data [@alias='umbracoNaviHide']) != '1'] ">
         <xsl:value-of select="umbraco.library:GetXmlNodeById($folder)/node [position() = $random]/data [@alias='image']"/>

        </xsl:when>
     <xsl:otherwise>
         <xsl:call-template name="GetRandomNode"/>
       </xsl:otherwise>
    </xsl:choose>

</xsl:template>

<!-- ============================================================= -->

</xsl:stylesheet>

cheers,
doug.

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tesuji 95 posts 139 karma points

Mar 02, 2010 @ 21:39

Thanks for the replies. Very helpful

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Arjan H. 226 posts 463 karma points c-trib

Mar 25, 2010 @ 21:56

Be careful using the XSLT provided by Douglas. The script can cause an infinite loop, since the template GetRandomNode keeps repeating itself when it bumps into a:

node [string(data [@alias='umbracoNaviHide']) != '1']

The biggest problem is when you try to save the XSLT, because saving the XSLT can mysterically cause the w3wp.exe process to absorb 100% of the CPU (on /umbraco/webservices/codeeditor.save.asmx) until you recycle the application pool or restart IIS althogether. I've tested the code on multiple servers, all with the same results. Does anyone have any idea why that happens?

I rewrote the XSLT to a very basic version that fetches a random nodeID from all pages of document type RunwayTextpage:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xsl:stylesheet [ <!ENTITY nbsp "&#x00A0;"> ]>

<xsl:stylesheet 
    version="1.0" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
    xmlns:msxml="urn:schemas-microsoft-com:xslt"
    xmlns:umbraco.library="urn:umbraco.library" xmlns:Exslt.ExsltCommon="urn:Exslt.ExsltCommon" xmlns:Exslt.ExsltDatesAndTimes="urn:Exslt.ExsltDatesAndTimes" xmlns:Exslt.ExsltMath="urn:Exslt.ExsltMath" xmlns:Exslt.ExsltRegularExpressions="urn:Exslt.ExsltRegularExpressions" xmlns:Exslt.ExsltStrings="urn:Exslt.ExsltStrings" xmlns:Exslt.ExsltSets="urn:Exslt.ExsltSets" 
    exclude-result-prefixes="msxml umbraco.library Exslt.ExsltCommon Exslt.ExsltDatesAndTimes Exslt.ExsltMath Exslt.ExsltRegularExpressions Exslt.ExsltStrings Exslt.ExsltSets ">

<xsl:output method="xml" omit-xml-declaration="yes"/>
<xsl:variable name="documentTypeAlias" select="string('RunwayTextpage')"/>

<xsl:param name="currentPage"/>

<xsl:template match="/">
    <xsl:variable name="randomNodeID">
        <xsl:call-template name="GetRandomNodeID"/>
    </xsl:variable>

    <p><xsl:value-of select="$randomNodeID"/></p>
</xsl:template>

<xsl:template name="GetRandomNodeID">
    <xsl:variable name="numNodes" select="count($currentPage/ancestor-or-self::node[@level = 1]//node[@nodeTypeAlias = $documentTypeAlias and string(data [@alias='umbracoNaviHide']) != '1']) "/>
        <xsl:variable name="random" select="floor(Exslt.ExsltMath:random() * $numNodes) + 1"/>

    <xsl:if test="$currentPage/ancestor-or-self::node[@level = 1]//node[@nodeTypeAlias = $documentTypeAlias] [position() = $random]">
        <xsl:value-of select="$currentPage/ancestor-or-self::node[@level = 1]//node[@nodeTypeAlias = $documentTypeAlias] [position() = $random]/@id"/>
    </xsl:if>
</xsl:template>

</xsl:stylesheet>