Function checkAndCompleteFlow

clientapi/routing/register.go:828–851

checkAndCompleteFlow checks if a given registration flow is completed given a set of allowed flows. If so, registration is completed, otherwise a response with

(
	flow []authtypes.LoginType,
	req *http.Request,
	r registerRequest,
	sessionID string,
	cfg *config.ClientAPI,
	userAPI userapi.ClientUserAPI,
)

// a set of allowed flows. If so, registration is completed, otherwise a
// response with
func checkAndCompleteFlow(
	flow []authtypes.LoginType,
	req *http.Request,
	r registerRequest,
	sessionID string,
	cfg *config.ClientAPI,
	userAPI userapi.ClientUserAPI,
) util.JSONResponse {
	if checkFlowCompleted(flow, cfg.Derived.Registration.Flows) {
		// This flow was completed, registration can continue
		return completeRegistration(
			req.Context(), userAPI, r.Username, r.Password, "", req.RemoteAddr, req.UserAgent(), sessionID,
			r.InhibitLogin, r.InitialDisplayName, r.DeviceID, userapi.AccountTypeUser,
		)
	}
	sessions.addParams(sessionID, r)
	// There are still more stages to complete.
	// Return the flows and those that have been completed.
	return util.JSONResponse{
		Code: http.StatusUnauthorized,
		JSON: newUserInteractiveResponse(sessionID,
			cfg.Derived.Registration.Flows, cfg.Derived.Registration.Params),
	}
}

// completeRegistration runs some rudimentary checks against the submitted
// input, then if successful creates an account and a newly associated device