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VOSAMP -- SAMP cmdline tool
Usage:
% vosamp [-hvd] [-t to] [-p pattern] [-f file] <cmd> [args ...]
where <cmd> command to process
-h print help summary
-v verbose output
-d debug output
-m handle multiple messages
-s <sender> handly only msgs from <sender>
-t <to> send to specified app (or all)
-p <pattern> message pattern: sync|async|notify
-f <file> send all commands in the file
Commands:
snoop print all received messages
send <mtype> [<args> ...] generalized <mtype> message send
status print Hub availability
list list all registered clients
access <appName> print <appName> availability
handle <mtype> wait for <mtype> message
exec <cmd> execute a client command
setenv <name> <value> set an environment value
getenv <name> get an environment value
setparam <name> <value> set a parameter value
getparam <name> get a parameter value
load <url> load the image/table
loadImage <url> load the named image
loadVOTable <url> load the named VOTable
loadFITS <url> load the named FITS bintable
loadSpec <url> load the named spectrum
loadResource <ivorn> load the named VO Resource
pointAt <ra> <dec> point at given coords
showRow [<url>] [<tblId>] <row> highlight specified row
selectRows [<url>] [<tblId>] <rows> select specified rows
bibcode <bibcode> load the bibcode
==============================================================================
VOSESSION -- Session manager for inter-desktop messaging
VOSAMP reads its command either from stdin, a named command file (e.g.
as from a VOSAMP-shell interpreter), or from a socket created when the proxy
process is created. This socket is created on an inet port that may be
visible to the whole internet, or on a private port restricted by local
system administrators to trusted clients (e.g. port 8080 if that is a
general service provided by a site, or the default port 4000 for sites
willing to open a firewall hole).
An example sequence of SAMP commands would be something like
% vosamp listClients
% vosamp loadVOTable foo.xml
where the first command establishes a SAMP connection, and the second would
forward the CLI command to the (already running) proxy client without
establishing a new-application context.
In this model, a proxy VOSAMP app reading from an inet socket opens
the possibility of using this proxy from a remote host that can send a
command from a trusted machine. For example,
On host A:
% vosamp start # start proxy client on host A (140.252.1.86)
On host B:
% vosamp --proxy=140.252.1.86:4000 loadVOTable foo.xml
where the '140.252.1.86' is the machine running the intial VOSAMP task,
'4000' is the inet port that proxy is reading commands, and the remainder
of the commandline are args to be passed thru as it they were issued from
the local host. Local data (e.g. the 'foo.xml' file) is sent to the remote
before executing the command, file:// URL's are rewritten so the file
reference remains valid on the remote machine (http:// URLs are unchanged).
SAMP Session Manager: (In development)
By using the proxy client, we can send commands to a VOSAMP application
from a remote machine, but this is not quite the same as federating two (or
more) desktops in a shared session. We are also limited by the ability to
bypass firewalls in order to connect to the proxy client. The solution then
is to have a public "session manager" service that serves as an alternate
input source to the proxy client and will acto to forward message from one
machine to the others. For example,
+-------------+
| Session Mgr |
+-------------+
^
/ \
/ \
+-------------------------+ +-------------------------+
| Topcat \ | | / Topcat |
| Hub - VOSAMP | | VOSAMP - Hub |
| Aladin / | | \ IRAF |
+-------------------------+ +-------------------------+
Host A Host B
Since the session manager is on a public host, the VOSAMP on each machine
makes an outgoing client connection and sets up that socket to receive
commands and subscribes to all message types so that SAMP messages received
on the local machine can be forwarded back to the session manager and then
on to other machines in the session. For example, the Aladin on Host A
broadcasts an image.load.FITS message, the VOSAMP on Host forwards the
message to the session manager than then passes it on to the VOSAMP on
Host B for rebroadcast. In this way the message is seen on both desktops
transparently. When local data is being used, this is uploaded to the
session manager for storage in a web-accessible area, the forwarded message
is then rewritten to use the URL and is accessed only when needed.
Sessions are created/joined with no special setup required, e.g.
% vosamp --session=foo e.g. commandline tool
or
voc.vosamp ("session=foo") e.g. from language API
The VOSAMP in this case would contact the session manager to join the list
of machines in session 'foo', this session would be created if it did not
already exist and sessions quietly end when the VOSAMP proxies timeout due
to inactivity or are shut down explicitly. There is no need for formal
security since it is up to the parties in the session to agree on and share
the session name of their choosing. Applications written using the language
bindings can participate in sessions by simply calling the VOSAMP task to
create the proxy regardless of whether it is used explicitly for messaging.
=============================================================================
#define DEF_PORT 4433 /* Session Mgr contact port */
#define MAX_SESSIONS 64 /* Max sessions to manage */
#define MAX_CLIENTS 64 /* Max clients in each session */
#define SZ_IPSTR 16 /* Size of an IP string */
typedef struct {
int port; /* connection port */
char hostIP[SZ_IPSTR]; /* host IP address */
} Client, *ClientP;
typedef struct {
int nclients; /* number of clients */
Client *clients[MAX_CLIENTS]; /* clients in session */
char dataCache[SZ_LINE]; /* path to local data cache */
} Session, *SessionP;
#define CALLBACK 0 /* mgr sends callback port */
#define QUIT 1 /* mgr sends disconnect/client retires */
#define SEND 2 /* mgr/client forwards cmd */
#define READY 3 /* mgr ready on port */
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