Getting Channels from the Clearinghouse
You might be wondering:
"So, I've heard I can get nifty channels for my uPortal from the Clearinghouse. What does this mean? Where is it? How might I get them? What might I do with them once I've got them?"
Wonder no more!
What is the Clearinghouse?
Unfortunately, we use the term "Clearinghouse" loosely and you'll need to look a few places for nifty channels.
Clearinghouse uPortal and the Contributions Channel
One distribution mechanism for uPortal channels is a special channel in the Clearinghouse uPortal instance. The Clearinghouse uPortal instance is a uPortal deployed onto JA-SIG's infrastructure server. It includes a channel that provides a listing of highly structured data about contributions and available plugins, primarily associated with uPortal but a few others as well. Some of these can be downloaded directly from this channel, but many of them are actually hosted elsewhere and the channel just provides information and a link.
There are some downsides to using this mechanism for distributing nifty channels. One is that people have to log in before they can get at this channel, so there's a barrier to entry and discovery for widgets hosted here. Another (related) downside is that this service is not available for generic search engine indexing, such that channels only available in this forum don't typically show up on Google searches.
Fortunately, there are other ways to distribute uPortal plugins that overcome these limitations. Unfortunately, the plurality of channel distribution mechanisms somewhat complicates the landscape.
Formally, "the Clearinghouse" is this uPortal instance running on "JA-SIG's server".
JA-SIG Confluence Wiki
Informally, people have referred to JA-SIG's whole server as "the Clearinghouse". That usage of the word is now discouraged as ambigious. Nonetheless, channels are available through the JA-SIG server via other mechanisms than the JA-SIG uPortal instance. One such place is this Confluence wiki. This uPortal Channels space is especially likely to contain channels, but you can search the whole wiki.
Confluence is the preferred way to post quick smallish channels for sharing.
Attachments to the wiki are stored in a special directory assocated with the Confluence web application on the JA-SIG server.
JA-SIG CVS
JA-SIG hosts source control space in which institutions can share and collaborate upon source code. Some channels, and often the latest neatest enhancements to channels, are available only from this source control.
There's a FishEye view on JA-SIG source control.
Source control is by far the preferred way for multiple schools to collaborate upon a uPortal plugin.
CVS files are stored in a repository on JA-SIG's server.
What do I do with the channel once I've got it?
Once you've downloaded a channel from the wiki or from the Clearinghouse uPortal contributions channel, or checked it out from CVS, exactly what you'll need to do to get it into your portal varies from plugin to plugin. Typically, channels from CVS will always need to be built, whereas the typically zip files from the wiki or from the Clearinghouse sometimes include pre-built .jars and other artifacts that you can attempt to use. Building from source is always a good idea, because then you have more assurance about what you're getting and, unfortunately, in many cases you'll need to do this to afford minor tweaks.
Dropping binaries into your portal typically involves adding .class files to /WEB-INF/classes/, adding .jar files to /WEB-INF/lib/, or both. There are also typically resources associated with the channel which at deploy time need to go into /WEB-INF/classes/.
Rebuilding your portal to include channels from source typically involves dropping source files into your uPortal source directory (with folders reflecting packaging), resources into the directories in the webpages directory, and running the "build" or "deploy" Ant target.