I was tasked a few months ago to rotate an image on a site randomly. Ordinarily this would not be an issue but the image was a css background image and I really didn’t have the ambition to rewrite the css and page html to do this. Thankfully my laziness paid off, because I found a solution while looking through some php code for wordpress.

I ran into this template that I liked, but wanted to change the header image. I changed it, uploaded it and refreshed the page, but NOTHING changed. I spent a good 5 minutes on this before checking the css to see what was going on. Instead of finding a path to an image in the css for the background, I found a path to a file named rotate.php. The script was written by Matt Mullenweg (http://photomatt.net/scripts/randomimage) and seemed simple enough to me. What I liked about this script is that it didn’t require managing a bunch of images. If you want an image you simply stick it in a predefined directory and point to that directory.

I decided to rewrite this in coldfusion and within a few minutes I had a working. It is rather simple. Define your folder, define your extensions and define the url path to the folder and you are done. You will find the code below.


<cftry>
<!—
created by Andrew Alba >> http://www.albawebstudio.com
This will grab images from specified folder and randomly display them
You will only need to modify the three variables below
—>

<!— Insert the absolute path (with trailing slash) to the images.
“/home/mysite/public_html/images/” or “/www/mysite/web/images/random/”
If the images are in the same directory as
this script you can leave it as shown file
—>


<cfset folder = “#GetDirectoryFromPath(GetBaseTemplatePath())#”>

<!— List of allowed extensions (separate with space) —>
<cfset ext = “jpg jpeg png gif”>

<!— Insert the URL to the folder that contains the images —>
<cfset url_image_path = “http://www.homeshq.com/gfx/promotion/”>


<!— do not edit below this point —>
<!— lets get the contents of the folder —>
<cfdirectory directory=“#folder#” action=“list” name=“filelisting”>

<!— pull just file names out of the list —>
<cfset fileList = “”>
<cfoutput query=“filelisting”>
<cfif filelisting.type is “file”>
<cfset fileList = listappend(fileList,filelisting.name)>
</cfif>
</cfoutput>


<!— now we can create a new list of files —>
<cfset new_fileList = “”>
<cfloop list=“#fileList#” index=“i” delimiters=“,”>
<!— lets use our list of extensions to
weed out the files types we don’t want —>
<!— now we grab just the extension —>

<cfset file_ext = listlast(i,“.”)>
<!— if it finds file_ext is acceptable as per
ext then it adds it to the array —>
<cfif listfindnocase(ext,file_ext,” “)>
<cfset new_fileList = listappend(new_fileList,i)>
</cfif>
</cfloop>

<!— now to choose random number from the list —>
<cfset image_file =
listgetat(new_fileList,randrange(1,listlen(new_fileList),“SHA1PRNG”),“,”)>

<cflocation
url=“#url_image_path##image_file#?rand=#randrange(1,999999999,”SHA1PRNG“)#”
addtoken=“no”>

<cfcatch type=“any”></cfcatch>
</cftry>