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Each profile flow is composed of a set of actions which perform some part of the overall processing necessary to generate the appropriate response. Requests pass from action to action until the response is complete and returned to the requester. While at the high level, there are "actions" to perform user authentication, attribute resolution, and response signing, the actual implementation of each action is much more fine grained. The details of the profile handlers and stages are discussed in message handling/processing chapter.
When an action is performing its work, it may in turn make calls to one or more of the IdP's services.
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