Rad Upload 4.0

After a long delay Rad Upload version 4.0 is finally out. It's a big change from the previous version. Almost everything that you could do with the old version of Rad Upload Plus, you can now do with the Rad Upload Standard Edition.

Some of the features that were previously available only in Rad Upload Plus such as the client side image resize feature, the ability to filter out unwanted file types and javascript events to name a few have now been included in the standard edition as well.

So what then is the difference between the plus and the standard editions? Well with Rad Upload Plus an upload is now resumable. If you suffer a network outage while a large file transfer is in progress, you no longer need to resend the whole collection of files all over again.

HTTP file uploads are governed by RFC 1867. It says that all the files should be combined together to created a single MIME message of the 'multipart/form-data' type. This message is then POSTed to the server. Which means that regardless of the number of files that you need to upload there is only one HTTP post.

Most server side scripting languages are not equipped to parse the MIME message unless the full data is available. If there is only partial data, it will be discarded. As a result resumable uploads are normally not possible with RFC 1867.

When using Rad Upload Plus applet's resumable mode, it will not obey RFC 1867. If there's more than one file to upload there will be more than one HTTP posts. If any of the files are greater than 512kb then there will be multiple posts for each file. Since files are posted one at a time, they need to be reassembled at the server. And code to do just that is included in the download.

The server side handler code, can be edited to carry out any post upload processing such as creating database records or sending out email notifications.