SAMP (Simple Application Messaging Protocol) (
astropy.samp is a Python implementation of the SAMP messaging system.
Simple Application Messaging Protocol (SAMP) is an inter-process communication system that allows different client programs, usually running on the same computer, to communicate with each other by exchanging short messages that may reference external data files. The protocol has been developed within the International Virtual Observatory Alliance (IVOA) and is understood by many desktop astronomy tools, including TOPCAT, SAO DS9, and Aladin.
So by using the classes in
astropy.samp, Python code can interact with
other running desktop clients, for instance displaying a named FITS file in DS9,
prompting Aladin to recenter on a given sky position, or receiving a message
identifying the row when a user highlights a plotted point in TOPCAT.
The way the protocol works is that a SAMP “Hub” process must be running on the local host, and then various client programs can connect to it. Once connected, these clients can send messages to each other via the hub. The details are described in the SAMP standard.
astropy.samp provides classes both to set up such a hub process, and to
help implement a client that can send and receive messages. It also provides a
samp_hub which can run a persistent hub in its own
process. Note that setting up the hub from Python is not always necessary, since
various other SAMP-aware applications may start up a hub independently; in most
cases, only one running hub is used during a SAMP session.
The following classes are available in
SAMPHubServer, which is used to instantiate a hub server that clients can then connect to.
SAMPClient, which is used to create a SAMP client.
astropy.samp is a full implementation of SAMP V1.3. As well as the Standard
Profile, it supports the Web Profile, which means that it can be used to also
communicate with web SAMP clients; see the sampjs library examples for more details.
- Starting and Stopping a SAMP Hub Server
- Sending and Receiving Tables and Images over SAMP
- Communication between Integrated Clients Objects
- Embedding a SAMP Hub in a GUI
This code is adapted from the SAMPy package written by Luigi Paioro, who has granted the Astropy Project permission to use the code under a BSD license.