How do I authenticate users with a 3rd party web site

Example scenarios

• You have another web application that your users log into with a username/password.
• You have a directory or web page protected by .htaccess / .htpasswd
• You know of an internet site (running whatever web software) which have users that you'd like to invite to your wiki
• You have any URI you can point your browser to and get a standard browser login dialog for which you and your colleagues have access

Requirements

The web application / remote site / whatever needs to expose a single URI which requires authentication. 

1. The URI needs to return an HTTP status 401 (unauthorized) for anonymous users or when credentials were not provided.
2. The URI needs to return an HTTP status 401 for invalid or unknown credentials.
3. The URI needs to return an HTTP status 200 if valid credentials are provided. 

A simple test of all of these requirements is to point your web browser to this URI. If you get a browser based login dialog then 1 is satisifed. If you enter invalid credentials and the same dialog comes up, 2 is satisfied. If you enter valid credentials and the dialog goes away and you see some sort of content then 3 is satisfied.

Downsides

Since only user credentials are getting transmitted, groups will not work for this authentication provider. 

Setup

Add the HttpPassThroughService authentication provider by logging into your wiki as an admin and going to control panel -> service management.

Add a local service with type authentication.

Enter the SID:

http://services.mindtouch.com/deki/draft/2007/07/http-authentication 

Enter your URI of choice a configuration setting "authentication-uri" (no quotes).

Type a description that users will see from the login page. Make sure it's enabled and optionally set it as the default. Save the service.

Troubleshooting and common issues

• Check the logs of your remote service as well as the MindTouch logs (in bin/logs)
• Use an http sniffer to see whats getting sent
• Get help at the technical forum @ http://forums.opengarden.org and stop by the irc channel: irc.freenode.net #opengarden