Daemons

In the Pipes section I showed some examples of how servers can be built using the pipe_open function. Such an approach is fine if you only want to use one protocol or address type. But real-world servers may need to run on multiple routes, address, and interfaces. The Daemon class offers some convenience methods for servers.

Hint

It’s easy to use the Daemon class. Simply inherit from Daemon in a child class. Your class should have a msg_cb function for incoming messages. The class can store any state you need.

async def add_listener(self, proto, route)

Add a new service to the daemon. Proto is TCP or UDP. Route is a Route object returned from a route pool or the route function from Interface.

async def listen_all(self, proto, port, nic):

Listen on all addresses on a machine. The need for the NIC parameter is as a standard function prototype for consistency. When you listen to all addresses the service may be accessible from the Internet and will be accessible on the LAN and loopback interface.

async def listen_loopback(self, proto, port, nic):

Start listening on the loopback address. Whether it binds to IP4 / IP6 is based on the supported address families for the NIC you provide. This function is useful for creating servers you want to make accessible on just that computer. P2PD’s own rest_api and toxid use this method.

async def listen_local(self, proto, port, nic):

For IPv6 this function listens on a NICs link-local addresses. For IPv4 it will listen on the NICs private addresses. For the latter – if there are forwarding rules setup or the node is not behind a NAT – this could mean making the service public.