How to select a random image from files in a directory using typoscript? - typo3

Question

I'm using Typo3 4.5.3 and I have image files in a directory from which I want to randomly select one to display on the current page, but I can't seem to get the typoscript right to make listnum = rand work. Here's my extension template:
# Pick a random image to display
temp.banner = IMAGE
temp.banner {
file {
height = 165
width = 954
import {
filelist = {$templatePathPrefix}images/banners | jpg,jpeg,png,gif | name | | 1
listNum = rand
}
}
params = class="bannerPic"
}
If I change the listnum setting to 0, 1, etc. it inserts the corresponding img HTML into the page. Setting it to 'last' also works, but rand always inserts the first image no matter how many times I refresh. Since I can select specific images (0, 1, ...) I know the general setup works, just not the random selection.
I've seen TS for various other uses of rand which wrap the outer object in a COA_INT object, but that didn't work for me either. Did I miss something about where to place the listNum = rand? I'm pretty new at Typo3 so lots of it is still pretty opaque to me at this point (or does it show?). Thanks for any insight you can provide.

Answer 1

mak_stdwrapextended extension adds the possibility to use rand with listNum.
Works well on 4.5.

Answer 2

I would not recommend you to do a random selection via TypoScript. Since you want a random image everytime you load the page, your random element must be a USER_INT or COA_INT element and is therefore not cacheable.
A simple solution for this is to do it via JavaScript. You define a default image if JavaScript is not available on the client, and a JavaScript that randomly select an image. With this solution, you get a random image everytime, and your content is fully cacheable.
The following TypoScript code can give you some inspiration for this. It basically reads out Image-Elements from the border collumn and generates JavaScript to output them randomly. Also, the images are linkable.
lib.teaser = COA
lib.teaser.10 = CONTENT
lib.teaser.10 < styles.content.getBorder
lib.teaser.10 {
slide = -1
table=tt_content
select{
begin = 0
max = 1
#language
languageField=sys_language_uid
#from wich column
where=colPos=3
}
wrap=<div class="teaserimage">|</div>
renderObj=COA
#image with gallery function
renderObj.10 = COA
renderObj.10 {
stdWrap.required=1
# get image
10 = IMAGE
10 {
#if not empty
required=1
file.import=uploads/pics/
file.import.field=image
#file.width=266
#file.height=180
file.import.listNum = 0
stdWrap.insertData=1
params = id="imgbig_{TSFE:currentRecord}"
imageLinkWrap < tt_content.image.20.1.imageLinkWrap
imageLinkWrap.typolink.ATagParams = id="link_imgbig_{TSFE:currentRecord}"
imageLinkWrap.typolink.ATagParams.stdWrap.insertData=1
}
# standard image configuration from tt_content
10.altText < tt_content.image.20.1.altText
10.titleText < tt_content.image.20.1.titleText
10.longdescURL < tt_content.image.20.1.longdescURL
# random function for gallery images
30 = COA
30 {
stdWrap.required=1
stdWrap.dataWrap(
<script type="text/javascript">
/* <![CDATA[ */
var imgArray = new Array(|);
var randnum = Math.round(Math.random()*(imgArray.length-1));
document.getElementById('imgbig_{TSFE:currentRecord}').src ='uploads/pics/' + imgArray[randnum];
/* ]]> */
</script>
)
# first gallery image
10 = TEXT
10.field = image
10.listNum.splitChar=,
10.listNum=0
10.if.isTrue.field=image
10.if.isTrue.listNum=1
10.if.isTrue.listNum.splitChar=,
10.dataWrap = "|"
# other gallery images
20 = TEXT
20.field = image
20.split {
token = ,
cObjNum = 1
1 = COA
1.if.isPositive.data = TSFE:register|SPLIT_COUNT
1 {
10 = TEXT
10.data = current:1
10.dataWrap = ,"|"
}
}
}
# random function for gallery links
40 = COA
40 {
stdWrap.required=1
stdWrap.dataWrap(
<script type="text/javascript">
/* <![CDATA[ */
//var imgLinkArray = new Array(randnum);
var imgLinkArray = new Array(|);
if(document.getElementById('link_imgbig_{TSFE:currentRecord}')) document.getElementById('link_imgbig_{TSFE:currentRecord}').href = imgLinkArray[randnum];
/* ]]> */
</script>
)
# first gallery link
10 = TEXT
10.field = image_link
10.listNum.splitChar=,
10.listNum=0
10.dataWrap = "|"
10.typolink.parameter.field = image_link
10.typolink.returnLast = url
# other gallery links
20 = TEXT
20.field = image_link
20.split {
token = ,
cObjNum = 1
1 = COA
1.if.isPositive.data = TSFE:register|SPLIT_COUNT
1 {
10 = TEXT
10.data = current:1
10.dataWrap = ,"|"
10.typolink.parameter.data = current:1
10.typolink.returnLast = url
}
}
}
}
}

Answer 3

only typo3 V4.6 and above has listNum = rand in the core, see this http://forge.typo3.org/issues/16180
for typo3 V4.5 you have to extend tslib/the class.tslib_content.php
add this to localconf.php:
$TYPO3_CONF_VARS['FE']['XCLASS']['tslib/class.tslib_content.php'] = PATH_site.'fileadmin/template/class.ux_tslib_content.php';
and add this code to class.ux_tslib_content.php:
<?php
/***************************************************************
* Copyright notice
*
* (c) 1999-2008 Kasper Skaarhoj (kasperYYYY#typo3.com)
* All rights reserved
*
* This script is part of the TYPO3 project. The TYPO3 project is
* free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* The GNU General Public License can be found at
* http://www.gnu.org/copyleft/gpl.html.
* A copy is found in the textfile GPL.txt and important notices to the license
* from the author is found in LICENSE.txt distributed with these scripts.
*
*
* This script is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* This copyright notice MUST APPEAR in all copies of the script!
***************************************************************/
/**
* Contains classes for Content Rendering based on TypoScript Template configuration
*
* $Id: class.tslib_content.php 4254 2008-09-27 13:35:44Z dmitry $
* Revised for TYPO3 3.6 June/2003 by Kasper Skaarhoj
* XHTML compliant
*
* class tslib_cObj : All main TypoScript features, rendering of content objects (cObjects). This class is the backbone of TypoScript Template rendering.
*
* #author Kasper Skaarhoj <kasperYYYY#typo3.com>
*/
/**
* This class contains all main TypoScript features.
* This includes the rendering of TypoScript content objects (cObjects).
* Is the backbone of TypoScript Template rendering.
*
* There are lots of functions you can use from your include-scripts.
* The class "tslib_cObj" is normally instantiated and referred to as "cObj".
* When you call your own PHP-code typically through a USER or USER_INT cObject then it is this class that instantiates the object and calls the main method. Before it does so it will set (if you are using classes) a reference to itself in the internal variable "cObj" of the object. Thus you can access all functions and data from this class by $this->cObj->... from within you classes written to be USER or USER_INT content objects.
*
* #author Kasper Skaarhoj <kasperYYYY#typo3.com>
* #package TYPO3
* #subpackage tslib
* #link http://typo3.org/doc.0.html?&tx_extrepmgm_pi1[extUid]=270&cHash=4ad9d7acb4
*/
class ux_tslib_cObj extends tslib_cObj{
/**
* Exploding a string by the $char value (if integer its an ASCII value) and returning index $listNum
*
* #param string String to explode
* #param string Index-number. You can place the word "last" in it and it will be substituted with the pointer to the last value. You can use math operators like "+-/*" (passed to calc())
* #param string Either a string used to explode the content string or an integer value which will then be changed into a character, eg. "10" for a linebreak char.
* #return string
*/
function listNum($content,$listNum,$char) {
$char = $char ? $char : ',';
if (t3lib_div::testInt($char)) {
$char = chr($char);
}
$temp = explode($char,$content);
$last = ''.(count($temp)-1);
if($listNum === 'rand'){ $listNum = rand(0,count($temp)-1);} //taywa added: rand feature!
$index=$this->calc(str_ireplace('last',$last,$listNum));
return $temp[$index];
}
}
?>