PluggableAuthService defines the following plugin types:
- Authentication plugins identify the user based on data in the request.
- Each PluggableAuthService must contain at least one authentication plugin.
- The PluggableAuthService defines an ordered set of authentication plugins, and queries them in order for each request. The first plugin to recognize a user returns the user, or raises an exception (e.g., for password mismatches). If no plugin returns a user, the PluggableAuthService returns an “anonymous” user (which may still have “extended” information added later).
- Challenge plugins alter the response to force the user to (re)authenticate, e.g. by redirecting it to a login form, or by setting the protocol-specific headers which initiate the desired challenge.
- Decorator plugins add propertysheets to a user, based on request data or on other data sources.
- These sources might include application data from the ZODB or from SQL, etc.
- They might also pull in user data from LDAP, ActiveDirectory, passwd files, etc.
- Group plugins add groups to the list of groups to which the user belongs, using request data or previously-added decorations.
- Update plugins write updates back to the data store from which they came (ZODB, SQL, LDAP, etc.)
- Validation plugins impose business-specified policies on user properties (particularly on login ID and password).
When using more than one plugin for authentication, only one challenge can be sent to the user - the one from the plugin at the top position of active Challenge Plugins configuration screen in the ZMI.
Nevertheless, you can instantiate the Challenge Protocol Chooser Plugin. Then you can assign, for instance, Cookie Auth for requests from the browser, and HTTP Basic Auth for requests via XML-RPC.
PluggableAuthService plugins are configured via the ZMI, or alternatively via an XML import / export mechanism. Each plugin is identified using a TALES path expression, which will be evaluated with an implied ‘nocall’ modifier; plugins are intended to be callables, with known argument signatures.