New features: RSS, Podcasts, Activity Feed

You can now subscribe to channels by RSS. A seperate RSS feed is offered for each format the channel is available in, so that you could, for example have a 320×240 WMV feed and a 640×480 Quicktime feed. The video is linked to as an enclosure so these feeds are, in effect, podcasts.

For formats which are iTunes-compatible, a one-click subscription link to iTunes is also provided (using the itpc handler).

At present, the podcast feeds don’t require a password so aren’t secure. I intend to enhance this in future, by using either personalized encrypted URLs or http authentication.

This is quite a simple feature but it makes it incredibly easy to publish a non-public podcast.

The activity feed is an at-a-glance view of new users, channels and episodes. It’s inspired by Basecamp’s Project Overview page.

New Release

• You can now invite other people to your site (e.g. teamname.deskcaster.com) to share videos with. 
• ‘Remember Me’ option when logging in
• A sample channel will be created automatically when a team site is created
• Other minor updates

Updates

• SWFUpload is implemented, so uploads now have a progress bar and larger files can be uploaded. Performance seems a little slow at the moment though.
• When you create an account you can now choose your own domain (e.g. mycompany.deskcaster.com). This is where your team members will log in and access videos. (The ability to invite team members will be in a future update).
• Minor change to page colour / layout (the green was making me sick!).

If you registered previously, you will need to re-register due to this update. Sorry for the inconvenience, I’ll ensure that isn’t required for future updates.

Flash-based Ajax-style Uploads to Amazon S3

POST upload support is a fairly new feature of S3. It was proposed in November 2007 and released for beta in December 2007. The documention is here.

This article documents some of the lessons I learned when integrating SWFUpload with S3. I’ve not got it working perfectly yet, but I’m very nearly there.

First, some background. Many sites already use S3 to store uploaded files, but until now this had required a two stage process:

• The user has to wait for the file to upload to the site, and then for it to be copied over to S3. So when using an upload component with a progress indicator there will be an additional delay even after it reaches 100%.
• Handling uploads in your app puts extra demand on your webserver

Direct uploads to S3 require a number of extra fields to be sent with the request. This is only supported in Flash 9. You cannot upload to S3 with Flash 8 or below.

Now, on to the implementation. Rather than trying to integrate everything at once, I recommend you take small steps:

First, get S3 uploads work using a standard file input button. Use this form generator to crytographically sign your upload policy, which gets sent with the request, and create your HTML. Note that whenever you make a chnage to the fields that get sent with your form, you’ll need to re-sign it.

Next, get SWFUpload working with a non-S3 site by studying the simple upload example. This will involve download all the necessary supporting files and making sure they’re in the right place.

Then there’s the fun try to combine the two. Here’s some important lessons I learned:

• SWFUpload has a debug option but it does not display error pages returned by S3, only the status code. To see the error page, use a HTTP analyser such as Charles.
• Host your swfupload.swf on your S3 account, then you don’t need to worry about crossdomain.xml
• S3 expects the file post name to be “File” rather than SWFUpload’s default of “Filedata”. You can change this using the file_post_name parameter.

Now, here’s the reason why I’m almost there but not quite. S3 allows to your set the response code for a successful upload to be 200, 201 or 204. But SWFUpload considers 201 and 204 to be error responses. So that leaves 200. But it doesn’t like responses with an empty body, which 200 returns, so it will hang at 100% even though the upload is successful. So what do you do?

• Be patient and wait for the new release of SWFUpload which should fix this
• Compile your own version of SWFUpload to circumvent this as described here.

I plan to do the latter, and will share my modified SWFUpload here when done.

Introducing Deskcaster

Deskcaster was launched today to a very small group of testers. There’s still a lot of work to be done on it but I wanted to get it in front of people as early as possible so that I can begin to prioritise the required functionality.