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

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• ::= [ ] [ "e" | "E" [ ] ]A floating point value is encoded as a mantissa with an OPTIONALpreceding sign followed by an OPTIONAL exponent part introducedwith the character “e” or “E”. There is no guarantee about the largestor smallest values which can be represented or about the number ofdigits of precision which are significant, since these will depend on theprocessing environment at decode time.• ::= "0" | "1"A boolean value is represented as an integer: zero represents false, andany other value represents true. 1 is the RECOMMENDED value torepresent true.The numeric types are based on the syntax of the C programming language,since this syntax forms the basis for typed data syntax in many otherlanguages. There may be extensions to this list in future versions of thisstandard.Particular MType definitions may use these conventions or devise theirown as required. Where the conventions in this list are used, message documentationSHOULD make it clear using a form of words along the lines “thisparameter contains a SAMP int”.3.5 Registering with the HubA client registers with the hub to:1. establish communication with the hub2. advertise its presence to the hub and to other clients3. obtain registration informationThe registration information is in the form of a map containing data itemswhich the client may wish to use during the SAMP session. The hub MUSTfill in values for the following keys in the returned map:samp.hub-id — The client ID which is used by the hub when it sends messagesitself (rather than forwarding them from other senders). For instance,this ID will be used when the hub sends the samp.hub.event.shutdownmessage.samp.self-id — The client ID which identifies the registering client.These keys form part of an extensible vocabulary as explained in Section 2.6.In most cases a client will not require either of the above IDs for normal14
SAMP operation, but they are there for clients which do wish to know them.Particular Profiles may require additional entries in this map.Immediately following registration, the client will typically perform someor all of the following OPTIONAL operations:• supply the hub with metadata about itself, using the declareMetadata()call• tell the hub how it wishes the hub to communicate with it, if at all(the mechanism for this is profile-dependent, and it may be implicit inregistration)• inform the hub which MTypes it wishes to subscribe to, using thedeclareSubscriptions() call3.6 Application MetadataA client may store metadata in the form of a map of key-value pairs in thehub for retrieval by other clients. Typical metadata might be the humanreadablename of the application, a description and a URL for its icon, butother values are permitted. The following keys are defined for well-knownmetadata items:samp.name — A one word title for the application.samp.description.text — A short description of the application, in plaintext.samp.description.html — A description of the application, in HTML.samp.icon.url — The URL of an icon in png, gif or jpeg format.samp.documentation.url — The URL of a documentation web page.All of the above are OPTIONAL, but samp.name is strongly RECOMMENDED.These keys form the basis of an extensible vocabulary as explained in Section2.6.3.7 MType SubscriptionsAs outlined above, an MType is a string which defines the semantics of amessage. MTypes have a hierarchical form. Their syntax is given by thefollowing BNF:::= [0-9a-z] | "-" | "_"::= | ::= | "." 15
Page 5 and 6: not discussed further in this docum
Page 7 and 8: Recipient: A Client that receives a
Page 9 and 10: 3. Await client registrations. When
Page 11 and 12: consumers if appropriate. As far as
Page 13: Although SAMP imposes no maximum on
Page 17 and 18: These keys form the basis of an ext
Page 19 and 20: Figure 2: Notification pattern2. Th
Page 21 and 22: protection from this eventuality; u
Page 23 and 24: Sends a message using the Synchrono
Page 25 and 26: 4.1 Data Type MappingsThe SAMP argu
Page 27 and 28: ::= [a-zA-Z0-9] | "-" | "_" | "." :
Page 29 and 30: string hub-url = readFromLockfile("
Page 31 and 32: dummy.version0.1-3The message itsel
Page 33 and 34: For each of the named parameters, a
Page 35 and 36: samp.hub.event.metadata:Arguments:i
Page 37 and 38: Return Values:noneDescription:Repor
Page 39 and 40: offers benefits such as meaning tha
Page 41: [6] http://plastic.sourceforge.net/

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