If you're working with Domino and Flex, sooner or later you're going to want to upload a file to the server. But, how?

Well, it's not simple (that is, it's nothing much like the way you're used to doing things) but it's not particularly hard either. Although you do have to do it all using script, rather than just plonking a file upload control on a form and letting the browser handle the rest.

In Flex you upload (and download for that matter) files using the FileReference class, which you create like this:

private var fileRef:FileReference = new FileReference();

The FileReference object has, amongst others, the following two methods: browse and upload, which let you browse for files and upload a file, respectively.

Unlike browsing for files using the HTML control, with Flex we can specify what type of files to upload, using a FileFilter, like so:

var fileFilter:FileFilter = new FileFilter("CSV Files", "*.csv");

Once we have a filter (or more than one if you like) we can browse for those file types like so:

fileRef.browse( [ fileFilter ] );

At which point the user would see a standard file browsing dialog for their OS.

Client-Side Validation

When the "file selected" event fires we can then do client-side testing of the file size.

if (fileRef.size > 10240) {
 Alert.show("That file is too big! Must be less than 10kb");
}

Try doing that in a browser!

Doing the Upload

Here comes the clever part. To POST the file to the server we use the upload method of the FileReference object. Like so:

var request:URLRequest = new URLRequest(
  basePath+"Demos.Flex.Upload?CreateDocument"
 );

fileRef.upload(request, "%%File.1");

Notice the second parameter passed to the upload method! Look familiar?

What this does is tell the server what "field name" to expect the file to be POSTed to. In our case we're using "%%File.1" which is a special name you need to use if you want to add your own file upload controls to forms. Note that for this to work you need to make a change to the server's Notes.ini file, as described in the last link.

A Simple Demo

Here's a simple demo of a Flex app which actually uploads files to this Domino server.

Once uploaded you should see a "open document" link appear at the bottom which will let you open the actual document in the browser, to prove the file is there. Have a play.

Source Code?

If you want to see all the code involved (there's not that much) then just right-click the Flex app above and choose "view source".