Publishing your Podcast - XML

There are various forms of web syndication available to web site owners. The syndicated distribution of media is known as Podcasting. In this article we will focus on delivering different audio and video (sometimes called Vodcasting) media to your subscribers.

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By: Nilpo/Developer Shed Staff Writer

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March 12, 2007

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In order to publish your Podcast you will need to create an RSS feed enclosure. I’m not going to go into great detail about creating the feed. You can find more information about creating RSS feeds in my article “Simple Web Syndication with RSS 2.0.”

The important point here is the use of a media enclosure. Enclosures are only available in RSS 2.0. The RSS 2.0 namespace includes an Enclosure tag for adding enclosures to your feed. Simply put, an enclosure is a way of supplying a media file with a particular feed item.

However, the use of an enclosure tag isn’t enough for a Podcast. We also want to include another feature specifically for mobile devices, or more appropriately, for the software used to manage your mobile device.

I’m talking about the iTunes namespace. There are a series of iTunes tags used specifically to mark an item for use on a mobile device. To implement this namespace we need to declare it in our RSS tag by linking to its DTD.

<?xml version="1.0"?>

<rss xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"

version="2.0">

Here we’ve opened our file by defining it as an XML document. Next, we’ve linked to the iTunes DTD to allow use of the iTunes namespace. Now we have to construct our channel and add items.

<?xml version="1.0"?>

<rss xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"

version="2.0">

<title>"News You Can't Use" by Developer Shed –

Audio</title>

Shed, Inc.</copyright>

<description>Fresh every Wednesday, "News You Can't

Use" by Developer Shed brings you the latest

offbeat tech news stories from around the world--stories

so crazy it's News You Can't Use!</description>

<item>

<title>Developer Shed's News You Can't Use for

2-28-2007</title>

<guid>http://images.devshed.com/technews/casts/video/
technews_02282007.mp3</guid>

</item>

</channel>

</rss>

This is what our weekly “News You Can’t Use” feed looks like after adding the iTunes DTD. While this feed is fully functional at this point, changing document type hasn’t done any good because we haven’t made use of the iTunes namespace.

Let’s begin with the channel section. There are several tags available that help us better define our channel’s content. After my channels description tag I add the following piece of code.

<itunes:subtitle>Weekly Audio Tech News Segment

</itunes:subtitle>

<itunes:author>Developer Shed, Inc.</itunes:author>

<itunes:summary>Fresh every Wednesday, "News You Can't

Use" by Developer Shed brings you the latest

offbeat tech news stories from around the world--stories

so crazy it's News You Can't Use!</itunes:summary>

<itunes:owner>

<itunes:name>Developer Shed, Inc.</itunes:name>

<itunes:email>technews@developershed.com</itunes:email>

</itunes:owner>

<itunes:category text="Technology">

<itunes:category text="Tech News" />

</itunes:category>

<itunes:explicit>no</itunes:explicit>

Okay, the subtitle, author, and summary tag pairs are pretty self-explanatory. Next we add the owner tag pair. This contains tag pairs that hold information about the channel owner. The email address provided should be an email where concerns about the channel can be received.

The category tags get a little tricky. There are predefined categories to choose from listed on Apple’s website. You can find these along with the complete tag listing by skimming through the iTunes namespace technical specification.

The first category tag is a surrounding pair with a text attribute that defines the main category listing. Multiple sub-categories can be listed inside of this pair within self-closing tags. You can list as many combinations as you like or need.

The explicit tag is used to rate the content of the media being offered. iTunes will not list a feed in its directory without an explicit tag. Possible values are “yes” if it contains explicit material, “no” if it doesn’t, or “clean” if it’s the edited version of an explicit recording.

<item>

<itunes:author>Developer Shed, Inc.</itunes:author>

<itunes:subtitle>Video news segment for the week of

February 28, 2007</itunes:subtitle>

<itunes:summary>Fresh every Wednesday, "News You

Can't Use" by Developer Shed brings you the

latest offbeat tech news stories from around the

world--stories so crazy it's News You Can't Use!

</itunes:summary>

<guid>http://images.devshed.com/technews/casts/video/
technews_02282007.mp3</guid>

<itunes:duration>5:31</itunes:duration>

<itunes:keywords>devshed, tech, news, developer, shed

</itunes:keywords>

</item>

Once you have created a channel you need to add your items. This is a basic example. Again we have our iTunes tags that are specific to the item itself. I’ve also added my enclosure.

The enclosure tag is a self closing tag. The first attribute is the URL to the media file. The second attribute defines the MIME type. The third attribute, which I’ve left out of this example, is the length in bytes of the file.

Once you’ve created your feed you can save it with either an XML or RSS extension and upload it to your website. Just provide a URL directly to the file. You can provide a URL specifically for iTunes users that will open the file directly in the iTunes software. Just replace the http:// in the URL with the itpc:// protocol instead.

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