gadget-ui.input.FileUploader example

I'm going to demonstrate how to use the new gadget-ui.input.FileUploader component in the gadget-ui library. First, we need an HTML page to host the component. This code comes directly from the /test folder in the gadget-ui repo:


<!doctype html>

	<title>gadget-ui File Uploader Test</title>
	<script src='../bower_components/modlazy/dist/modlazy.min.js'></script>
				"fileuploader.js < ../dist/gadget-ui.js",
			function() {
				console.log("All files have been loaded");

		body {
			font-size: 1em;

		select option {
			font-size: 1em;

		#fileUploadDiv {
			height: 500px;
			width: 500px;
			text-align: center;
			margin-top: auto;
			margin-bottom: auto;


	<p>Test the FileUploader control.</p>

	<div id="fileUploadDiv"></div>


I am using a small dependency loader called modlazy to load my assets. This page shows a div called fileUploadDiv that will host the component. Let's look at the fileuploader.js file:


var options = {
  uploadURI: "/test/fileuploader.upload.cfm",
  tags: "file upload",
  willGenerateThumbnails: true,
  title: "Upload Files",
  showUploadButton: false

filedialog = gadgetui.objects.Constructor( gadgetui.input.FileUploader, [ document.querySelector("#fileUploadDiv"), options ]);

The uploadURI specifies a CFML page  that should be compatible with Lucee and Adobe ColdFusion, although I am testing it with Lucee, so there could be bugs in the ACF implementation right now. We'll dig into that page in a minute.

Right now, what I want to show is how the component is being instantiated. Rather than use the new keyword, I have ported all of he gadget-ui code to use the built-in gadgetui.objects.Constructor method, which internally uses Object.create(). I have also included a new option, showUploadButton, so you can either have a drop zone, or have a drop zone and a file upload button.

On drop  or file select, the component cuts the file up into 1MB chunks and uploads the chunks one at a time. Let's have a look at the CFML receiver file:


	filePath = "#expandpath("./")#upload\";
	separator = iif(expandpath("./") contains "/",de("/"),de("\"));
	filePath = expandpath("./") & "upload" & separator;
	chunkPath = filePath & "temp" & separator & createUUID();
	inputStream = getPageContext().getRequest().getOriginalRequest().getInputStream();
	ioutil = createObject( "java", "" );
	outputStream = createObject( "java", "" ).init( chunkPath );
	ioutil.copy( inputStream, outputStream );

	contentLength = gethttprequestdata().headers['Content-Length']; = gethttprequestdata().headers['x-id'];
	args.filename = gethttprequestdata().headers['x-filename'];
	args.filesize = gethttprequestdata().headers['x-filesize'];
	args.part = gethttprequestdata().headers['x-filepart']; = gethttprequestdata().headers['x-parts'];

	if( args.part eq 1 ){
		fileId = createUUID();
		fileId =;
	args.temp_file = chunkPath; = fileId;
	FilePartDAO = new model.FilePartDAO();
	FileService = new model.FileService( filePath = filePath, FilePartDAO = FilePartDAO );
	file = FileService.upload( argumentcollection = args );

	if( args.part eq ){
		writeoutput( SerializeJSON( file ) );
		pc = getpagecontext();
		pc.setHeader("X-Id", fileId );


There is a lot going on in this code. Look at the use of Java input and output streams to copy the chunked data. I use Java classes here to guarantee good data coming through from the binary data POST. Note that I am using UUIDs to identify the chunks and store them in a temporary folder on the server, where they stay until they are re-assembled into the original file.

Also see the use of gethttprequestdata() to pull the headers for the chunked data. The x- headers are all custom headers created by the FileUploader component to track the file upload. x-filepart tells the server which part of the file is being uploaded, and x-parts tells the server how many total parts there are.

Next, note that this code takes place in a loop controlled by the FileUploader component. When the end of the loop is reached, the file upload is completed and a response is sent back to the client. 

The real work of the upload is being done in the FileService CFML component. This example uses a baseline implementation that uploads the file(s) to a destination folder on the server. Other implementations may store the file in MongoDB or other NoSQL stores. I will dig into the FileService component next time.