Multi-file Uploads with ColdFusion 9 in 5 Lines
ColdFusion 9 includes a new Flash-based page element for handling multiple file uploads. Many people have spent quite a bit of time solving this problem, but using ColdFusion 9, you could add this functionality to your site in just about 5 lines. It includes the functionality you'd expect from a multi-file upload element including things like the ability to specify a maximum number of files or a maximum file size. It's also fairly customizable using styles. So let's look at a basic example.
At its core, the new <cffileupload> tag only needs to be supplied a URL for the processing page. It also does not need to be placed inside a <cfform>. Here's my example page which will create a form element in the image on the right:
<html>
<head>
<title>CFFileUpload Example</title>
</head>
<body>
<cffileupload url="process.cfm" />
</body>
</html>
In order to handle the processing, a new action has been added to the <cffile> tag called "uploadall" which only requires the destination be supplied. Technically speaking, that's all you need on your processing page to make the form work. However, I ran into technical issues with this that the ColdFusion team helped me out with. The upload has an onComplete attribute that calls a JavaScript and passes it a json string. Even though I had not set that on my cffileupload, it seems that was causing my upload to bomb out after the first item. The lines following the cffile tag resolved that issue. This is why the title says 5 lines instead of 2 - but 5 lines for this level of functionality is still pretty amazing.
<cffile action="uploadall" destination="#expandPath('uploads')#" nameconflict="overwrite" />
<cfset str.STATUS = 200>
<cfset str.MESSAGE = "passed">
<cfoutput>#serializeJSON(str)#</cfoutput>
Obviously, in many cases you'll want to mess with more of the customization than in this very simple example. If you want to take a closer look at the customization options, the documentation for the tag can be found here.
Coldfusion tends to have that stuff already taken care of so it would be counterintuitive to require it now I think.
My security system involves checking session variables for each page to ensure the user has privileges to see the page. On loading the response page specified by the cffileupload url attribute, I can't send in the session variables, so the user cannot access the response page and the file is not uploaded.
Very much appreciate the answer but I use FileOpen etc. to upload files from the client - the huge advantage being that the entire file does not have to be loaded into memory. This allows for uploading of very large files and avoids the server issues that can arise if multiple large files are uploading simultaneously.
Mea culpa - I was suffering from a serious case of public stupidity. Please ignore my last two entries. I seemed to have forgotton some basic htmil theory. UG.