ColdFusion 8: URL Thumbnails
A reader asked me this morning if ColdFusion 8 can create images from URLs. This is often used to provide a snap shot of a remote site. Turns out this is relatively easy. Damon Cooper of Adobe showed an example of this a few weeks ago. It takes all of two tags:
<cfdocument src="http://www.raymondcamden.com" name="pdfdata" format="pdf" />
<cfpdf source="pdfdata" pages="1" action="thumbnail" destination="." format="jpg" overwrite="true" resolution="high" scale="25">
The first line simply uses cfdocument with the src attribute. I point to a URL (in this case, my blog) and store the result in a PDF variable.
Next I use the cfpdf tag to create a thumbnail. I specify the JPG format, use a high resolution, and set a scale to 25% just for the heck of it. Also note I only do page 1. By default the cfpdf/action="thumbnail" tag will create a thumbnail for each page of the PDF, but all we really want is the first page.
That's it. Done. Complete. Simple as pie. But of course I had to go a bit crazy and make a UDF out of it. The code below allows you to pass a URL (and an optional scale). It will then handle making the image, reading it into a CF8 Image object, deleting the file, and returning the object. You can then save it, or do whatever. For my tests, I did:
<cfset myimage = getThumbnail("http://www.coldfusionjedi.com",30)>
<cfimage action="writeToBrowser" source="#myimage#">
The "writeToBrowser" action lets me test without actually saving a file, but I believe it doesn't work in IE. (Not that I care.) Enjoy, and let me know how it works for you. I'll probably add options to let you specify an image type as well.
The image quality is pretty good I think. It is not the same as what you see from Firefox, but for a thumbnail, I think it works ok:
<cffunction name="getThumbnail" returnType="any" output="false">
<cfargument name="url" type="string" required="true">
<cfargument name="scale" type="numeric" required="false" default="25">
<cfset var pdfdata = "">
<cfset var prefix = replace(createUUID(),"-","_","all")>
<cfset var myimage = "">
<!--- make the pdf --->
<cfdocument src="#arguments.url#" name="pdfdata" format="pdf" />
<!--- write out the image --->
<cfpdf source="pdfdata" pages="1" action="thumbnail" destination="." format="jpg" overwrite="true"
resolution="high" scale="#arguments.scale#" imagePrefix="#prefix#">
<!--- read it in --->
<cfset myimage = imageNew(expandPath('./#prefix#_page_1.jpg'))>
<!--- clean it up --->
<cffile action="delete" file="#expandPath('./#prefix#_page_1.jpg')#">
<cfreturn myimage>
</cffunction>