SAMP — Simple Application Messag- ing Protocol Version 1.11 - IVOA

protection from this eventuality; users of the Asynchronous Call/Responsepattern may or may not wish to take their own steps.3.11 Operations a Hub Must SupportThis section describes the operations that a hub MUST support and theassociated data that MUST be sent and received. The precise details ofhow these operations map onto method names and signatures is Profiledependent.The mapping for the Standard Profile is given in Section 4.2.• map reg-info = register()Method called by a client wishing to register with the hub. The formof reg-info is given in Section 3.5. Note that the form of this call mayvary according to the requirements of the particular Profile in use. Forinstance authentication tokens may be passed in one or both directionsto complete registration.• unregister()Method called by a client wishing to unregister from the hub• declareMetadata(map metadata)Method called by a client to declare its metadata. May be called zeroor more times to update hub state; the most recent call is the onewhich defines the client’s currently declared metadata. The form ofthe metadata map is given in Section 3.6.• map metadata = getMetadata(string client-id)Returns the metadata information for the client whose public ID isclient-id. The form of the metadata map is given in Section 3.6.• declareSubscriptions(map subscriptions)Method called by a callable client to declare the MTypes it wishes tosubscribe to. May be called zero or more times to update hub state;the most recent call is the one which defines the client’s currently subscribedMTypes. The form of the subscriptions map is given inSection 3.7.• map subscriptions = getSubscriptions(string client-id)Returns the subscribed MTypes for the client whose public ID is client-id.The form of the subscriptions map is given in Section 3.7.21