PHP script to fetch info from Jamulus servers and return as JSON
Used as a back-end by Jamulus Explorer (github page) and also Jamulus.Live (github page).
Normally invoked as servers.php?directory=directory.server.host:port, which will
return data for all servers registered with that directory server.
Can also be invoked as servers.php?server=individual.server.host:port, which will
return data just for the specified individual server. Note that in this case,
the server name, city and country cannot be returned, as they are only available
from a directory server. By default, the hostname is returned in the name field
for a single server, but this can be overridden by providing a name as a query
parameter: servers.php?server=individual.server.host:port&name=My+Server+Name
Finally, it is possible to query a server's welcome message using
servers.php?query=individual.server.host:port, which will briefly initiate
an audio connection to the server, collect any welcome message returned,
and disconnect again. This happens quickly, so no additional client is displayed
to the other clients, but if a server is already full, it does not work.
In order to support "port2" detection, this back-end needs to be able to accept server replies coming from any port, not just from the expected port to which a request was sent.
To allow this, the server.php back-end sets its source port in a specific range,
22134-22149 (See the defines for CLIENT_PORT and CLIENT_PORTS_TO_TRY).
The system hosting the back-end needs to have its firewall configured to accept incoming
traffic to that specific port range from any IP address and any port number.