Runs in OPML Editor, which runs on Macintosh and Windows.
The machine running River3 does not need to be accessible over the Internet, but it must have an Internet connection for reading feeds.
All input comes in through a Dropbox folder. And all output is published to the same folder.
The input is this: a set of OPML reading lists, and a template.
The output: A folder with HTML files, one with logs, and another with JSON files that can plug into other river displays if needed.
The output folder is optionally mirrored on S3, so you don't have to fuss with how to make things public.
Here's a screen shot of the Dropbox folder.
River3 is not open source, but it is free to use for whatever you like.
You can run River3 from any folder that's accessible through the file system. You can use Dropbox, or other sharing software such as Google Drive or Microsoft's SkyDrive, or not share it at all.
You're going to need at least one OPML subscription list after basic setup, to put in your lists folder. So you might want to have that ready before-hand, although River3 will happily run with no lists. Here's a list of NY Times feeds I like to test with.
You can configure River3 to upload to S3 automatically. If you want to do that you should have your S3 credentials ready.
It's important that the folder path end with either a colon (on Mac) or a backslash (Windows).
If you want to use S3, you must also provide your S3 credentials on this prefs page.
If it's enabled, it scans as often as you tell it to, reading all the feeds each time, and routing new items to the rivers they belong to.
The subscription lists it scans are stored in the lists folder. They must be OPML formatted, and must have the .opml extension.
The resulting rivers are saved both as JSON in the rivers folder, and as HTML in the html folder.
The template is automatically initialized in the first run. It's in the templates folder. You can edit it to change the look of your rivers.
Each time we scan an item is added to the log for the day, in the logs folder.
You should keep an eye on the river3data.root file in Guest Databases/ops/datafiles/ in the OPML Editor folder. If it gets close to 2GB you have a problem. If you don't have too many feeds and you don't keep around too many days of data (that's a configuration setting) it shouldn't be a problem.
If you love River3 and want to get it working great, and help us continue testing and development, please join the Frontier-user mail list.
Questions here are less likely to be answered.