Coldfusion cfpdf thumbnail plus preview?

Question

we have a great deal of PDF content on our site. I have some perfectly usable CFPDF thumbnails generated from Page 1 of each PDF. I thought it would be nice to have the thumbnail jpg be a link such that when you click it, you either see the first page as is, or another preview at full scale is generated.

I am experimenting with using CFPDF's merge action, but without much luck so far. There does not seem to be a way to just extract a single page from the PDF -- only delete them.

Does anybody have any suggestions? I really do appreciate it! Thanks!

UPDATE: to try and clarify, here's the code I am using right now. Sorry for the confusion!

<cfset dir = expandPath("\images\thumbs")>
<cfif not directoryExists(dir)>
    <cfdirectory action="create" directory="#dir#">
</cfif>
<cfset firstPage = expandPath("\images\thumbs\firstPage.pdf")>

<cfpdf action="thumbnail"
source="source"
destination="#dir#" 
format="jpg" 
scale="40"
overwrite="yes"
pages="1" 
resolution="low">
<cfpdf action="merge"
source="sameSource"
pages="1"
destination="#firstPage#"
overwrite="yes">
<a href="firstPage.pdf" target="_blank"> 
<img src="thumbnail.jpg" style="border: 1px solid silver;">
</a>

Anyways I hope that explains better what I am trying to do. Like I said, this works, but firstPage.pdf is always just the one file -- what happens if several people are previewing different PDFs at the same time, for example?

Thanks!

Answer 1

(If I am understanding the question correctly ...)

Sure you can use merge to extract a single page:

<cfpdf action = "merge" 
    source="c:\dev\myFile.pdf"
    pages="10"
    name="singlePage" />

<cfcontent type="application/pdf" variable="#ToBinary(singlePage)#">    

what happens if several people are previewing different PDFs at the same time, for example?

Edit: Some of them will end up previewing the wrong page and/or thumbnail image ;) To avoid that, you must generate a unique file name each time, such as using getTempFile(), createUUID() &".pdf", etcetera.

Though technically you do not have to create a file. You can generate images/pdfs in memory only and serve them with cfcontent (like in the example above).

Answer 2

Its very easy

<cfpdf source="pdfdata" pages="1" action="thumbnail" destination="." format="jpg" overwrite="true" resolution="high" scale="25">

That will turn page one into a jpg