reticulum/Examples/Announce.py

##########################################################
# This RNS example demonstrates setting up announce      #
# callbacks, which will let an application receive a     #
# notification when an announce relevant for it arrives  #
##########################################################

import argparse
import random
import RNS

# Let's define an app name. We'll use this for all
# destinations we create. Since this basic example
# is part of a range of example utilities, we'll put
# them all within the app namespace "example_utilities"
APP_NAME = "example_utilities"

# We initialise two lists of strings to use as app_data
fruits = ["Peach", "Quince", "Date", "Tangerine", "Pomelo", "Carambola", "Grape"]
noble_gases = ["Helium", "Neon", "Argon", "Krypton", "Xenon", "Radon", "Oganesson"]

# This initialisation is executed when the program is started
def program_setup(configpath):
    # We must first initialise Reticulum
    reticulum = RNS.Reticulum(configpath)
    
    # Randomly create a new identity for our example
    identity = RNS.Identity()

    # Using the identity we just created, we create two destinations
    # in the "example_utilities.announcesample" application space.
    #
    # Destinations are endpoints in Reticulum, that can be addressed
    # and communicated with. Destinations can also announce their
    # existence, which will let the network know they are reachable
    # and autoomatically create paths to them, from anywhere else
    # in the network.
    destination_1 = RNS.Destination(
        identity,
        RNS.Destination.IN,
        RNS.Destination.SINGLE,
        APP_NAME,
        "announcesample",
        "fruits"
    )

    destination_2 = RNS.Destination(
        identity,
        RNS.Destination.IN,
        RNS.Destination.SINGLE,
        APP_NAME,
        "announcesample",
        "noble_gases"
    )

    # We configure the destinations to automatically prove all
    # packets adressed to it. By doing this, RNS will automatically
    # generate a proof for each incoming packet and transmit it
    # back to the sender of that packet. This will let anyone that
    # tries to communicate with the destination know whether their
    # communication was received correctly.
    destination_1.set_proof_strategy(RNS.Destination.PROVE_ALL)
    destination_2.set_proof_strategy(RNS.Destination.PROVE_ALL)

    # We create an announce handler and configure it to only ask for
    # announces from "example_utilities.announcesample.fruits".
    # Try changing the filter and see what happens.
    announce_handler = ExampleAnnounceHandler(
        aspect_filter="example_utilities.announcesample.fruits"
    )

    # We register the announce handler with Reticulum
    RNS.Transport.register_announce_handler(announce_handler)
    
    # Everything's ready!
    # Let's hand over control to the announce loop
    announceLoop(destination_1, destination_2)


def announceLoop(destination_1, destination_2):
    # Let the user know that everything is ready
    RNS.log("Announce example running, hit enter to manually send an announce (Ctrl-C to quit)")

    # We enter a loop that runs until the users exits.
    # If the user hits enter, we will announce our server
    # destination on the network, which will let clients
    # know how to create messages directed towards it.
    while True:
        entered = input()
        
        # Randomly select a fruit
        fruit = fruits[random.randint(0,len(fruits)-1)]

        # Send the announce including the app data
        destination_1.announce(app_data=fruit.encode("utf-8"))
        RNS.log(
            "Sent announce from "+
            RNS.prettyhexrep(destination_1.hash)+
            " ("+destination_1.name+")"
        )

        # Randomly select a noble gas
        noble_gas = noble_gases[random.randint(0,len(noble_gases)-1)]

        # Send the announce including the app data
        destination_2.announce(app_data=noble_gas.encode("utf-8"))
        RNS.log(
            "Sent announce from "+
            RNS.prettyhexrep(destination_2.hash)+
            " ("+destination_2.name+")"
        )

# We will need to define an announce handler class that
# Reticulum can message when an announce arrives.
class ExampleAnnounceHandler:
    # The initialisation method takes the optional
    # aspect_filter argument. If aspect_filter is set to
    # None, all announces will be passed to the instance.
    # If only some announces are wanted, it can be set to
    # an aspect string.
    def __init__(self, aspect_filter=None):
        self.aspect_filter = aspect_filter

    # This method will be called by Reticulums Transport
    # system when an announce arrives that matches the
    # configured aspect filter. Filters must be specific,
    # and cannot use wildcards.
    def received_announce(self, destination_hash, announced_identity, app_data):
        RNS.log(
            "Received an announce from "+
            RNS.prettyhexrep(destination_hash)
        )

        RNS.log(
            "The announce contained the following app data: "+
            app_data.decode("utf-8")
        )

##########################################################
#### Program Startup #####################################
##########################################################

# This part of the program gets run at startup,
# and parses input from the user, and then starts
# the desired program mode.
if __name__ == "__main__":
    try:
        parser = argparse.ArgumentParser(
            description="Reticulum example that demonstrates announces and announce handlers"
        )

        parser.add_argument(
            "--config",
            action="store",
            default=None,
            help="path to alternative Reticulum config directory",
            type=str
        )

        args = parser.parse_args()

        if args.config:
            configarg = args.config
        else:
            configarg = None

        program_setup(configarg)

    except KeyboardInterrupt:
        print("")
        exit()