Decode message on receive

balancesharing/balancesharing.py

@@ -14,18 +14,17 @@
 import json
 import os
 import struct
+import time
 from binascii import hexlify, unhexlify
 
-hexlify(struct.pack(">H", 437))
-
 QUERY_FOAF_BALANCES = 437
 REPLY_FOAF_BALANCES = 439
-
+CHAIN_HASH = r'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
+BTC_CHAIN_HASH = CHAIN_HASH
 foaf_network = None
 
 plugin = pyln.client.Plugin()
 
-
 # __version__ was introduced in 0.0.7.1, with utf8 passthrough support.
 try:
     if version.parse(lightning.__version__) >= version.parse("0.0.7.1"):
@@ -51,6 +50,7 @@ def get_funds(plugin):
     return outputs, channels
 
 
+# TODO: remove when finished, or keep for test cases
 def list_funds_mock():
     """"read funds from file"""
     dir_path = os.path.dirname(os.path.realpath(__file__))
@@ -62,79 +62,146 @@ def list_funds_mock():
 
 
 # TODO: we need to extend this, if we want to handle multiple channels per peer
-
-
 def get_channel(channels, peer_id):
     """"searches for ONE channel with the given  peer_id"""
     for ch in channels:
         if ch["peer_id"] == peer_id:
             return ch
-
     return None
 
 
+def encode_reply_foaf_balances(short_channels, amt_to_rebalance, plugin):
+    """Encode flow_value and amt_to_rebalance"""
+    """
+    H ->        type: short
+    32s ->      chain_hash: 32byte char
+    Q ->        timestamp: unsigned long
+    Q ->        amt_to_rebalance: unsigned long long
+    H ->        number_of_short_channels: unsigned short
+    {len*8}s -> short_channel_id
+    """
+    global REPLY_FOAF_BALANCES
+    global CHAIN_HASH
+
+    # fund_list = list_funds_mock()
+    # channels = fund_list["channels"]
+    #
+    # # TODO: remove mock
+    # mock_short_channels = []
+    # for ch in channels:
+    #     mock_short_channels.append(ch["short_channel_id"])
+    # short_channels = mock_short_channels
+
+    # time.time() returns a float with 4 decimal places
+    timestamp = int(time.time() * 1000)
+    number_of_short_channels = len(short_channels)
+    channel_array_sign = str(number_of_short_channels * 8) + 's'
+    plugin.log("Channel sign: {channel_array_sign}"
+               .format(channel_array_sign=channel_array_sign))
+    return hexlify(struct.pack(
+        "!H32sQQH", REPLY_FOAF_BALANCES, CHAIN_HASH.encode('ASCII'),
+        timestamp, number_of_short_channels, amt_to_rebalance)
+    ).decode('ASCII')
+
+
 def encode_query_foaf_balances(flow_value, amt_to_rebalance):
-    """Encode flow_value (char) and amount (unsigend long long) """
-    return struct.pack("!cQ", flow_value, amt_to_rebalance)
+    """Encode flow_value and amt_to_rebalance"""
+    """
+    H ->    type: short
+    32s ->  chain_hash: 32byte char
+    c ->    flow_value: char
+    Q ->    amt_to_rebalance: unsigned long long
+    """
+    global QUERY_FOAF_BALANCES
+    global CHAIN_HASH
+    return hexlify(
+        struct.pack("!H32scQ", QUERY_FOAF_BALANCES, CHAIN_HASH.encode('ASCII'), flow_value, amt_to_rebalance)).decode(
+        'ASCII')
 
 
 def decode_query_foaf_balances(data):
-    """Decode query_foaf_balances. Returns a byte and int"""
-    return struct.unpack("!cQ", data)
+    """Decode query_foaf_balances. Return type, chain_hash, flow_value and amt_to_rebalance"""
+    msg_type, chain_hash, flow, amt = struct.unpack("!H32scQ", unhexlify(data.encode('ASCII')))
+    chain_hash = chain_hash.decode('ASCII')
+    return msg_type, chain_hash, flow, amt
+
+
+def get_flow_value(flow):
+    if type(flow) is not int:
+        return None
+
+    if flow == 1:
+        return b'\x01'
+    elif flow == 0:
+        return b'\x00'
+    return None
+
+
+def get_amount(amt):
+    if type(amt) is not int or amt <= 0:
+        return None
+    return amt
+
+
+def log_error(msg):
+    plugin.log("Error in balancesharing plugin: {msg}".format(msg=msg))
 
 
 @plugin.method("foafbalance")
-def foafbalance(plugin):
+def foafbalance(plugin, flow, amount):
     """gets the balance of our friends channels"""
-    global foaf_network
-    foaf_network = nx.DiGraph()
-    flow_value = b'\x01'
-    amt_to_rebalance = int(123)
+    plugin.log("Building query_foaf_balances message...")
+    # Read input data
+    flow_value = get_flow_value(flow)
+    if flow_value is None:
+        log_error("argument 'flow_value' for function 'foafbalance' was not 0 or 1")
+        return
+
+    amt_to_rebalance = get_amount(amount)
+    if amt_to_rebalance is None:
+        log_error("argument 'amt_to_rebalance' for function 'foafbalance' was not valid")
+        return
+
     data = encode_query_foaf_balances(flow_value, amt_to_rebalance)
-    new_flow_value, new_amt_to_rebalance = decode_query_foaf_balances(data)
 
-    plugin.log(str(data))
-    plugin.log("New values: {flow_value}  {amt_to_rebalance}".format(
+    # todo: remove. only for debugging
+    msg_type, chain_hash, new_flow_value, new_amt_to_rebalance = decode_query_foaf_balances(data)
+    plugin.log("Test decoding: {msg_type} -- {chain_hash} -- {flow_value} -- {amt_to_rebalance}".format(
+        msg_type=msg_type,
+        chain_hash=chain_hash,
         flow_value=new_flow_value,
         amt_to_rebalance=new_amt_to_rebalance
     ))
 
-    reply = {}
-    info = plugin.rpc.getinfo()
-    #msg = r'01b5' + str(hexlify(struct.pack(">H", 437))) + '126182746121'
-    msg = r'01b5126182746121'
-
-    dir_path = os.path.dirname(os.path.realpath(__file__))
-    plugin.log(dir_path)
-
-    outputs, channels = get_funds(plugin)
+    global foaf_network
+    foaf_network = nx.DiGraph()
 
+    counter = 0
     for peer in plugin.rpc.listpeers()["peers"]:
         # check if peer is the desired state
         if not peer["connected"] or not has_feature(peer["features"]):
             continue
         peer_id = peer["id"]
 
-        res = plugin.rpc.dev_sendcustommsg(peer_id, msg)
-        plugin.log("RPC response" + str(res))
+        res = plugin.rpc.dev_sendcustommsg(peer_id, data)
+        plugin.log("Sent query_foaf_balances message to {peer_id}. Response: {res}".format(
+            peer_id=peer_id,
+            res=res
+        ))
+
+        counter = counter + 1
 
-    nid = info["id"]
-    reply["id"] = nid
-    reply["change"] = nid
+    nid = plugin.rpc.getinfo()["id"]
+    reply = {"id": nid, "num_sent_queries": counter}
     return reply
 
 
 def get_message_type(message):
-    """takes the 4 hex digits of a string and returns them as an integer 
+    """takes the 4 hex digits of a string and returns them as an integer
     if they are a well known message type"""
     assert len(message) > 4
     message_type = message[:4]
-    # >>> hexlify(pack(">H",437))
-    # b'01b5'
-    # >>> unpack(">H",unhexlify(b'01b5'))
-    # (437,)
-    # >>> unpack(">H",unhexlify(b'01b5'))[0]
-    return struct.unpack(">H", unhexlify(message_type))[0]
+    return struct.unpack(">H", unhexlify(message_type.encode('ASCII')))[0]
 
 
 def get_message_payload(message):
@@ -160,45 +227,47 @@ def helper_compute_channel_balance_coefficients(channels):
     return channels
 
 
-def handle_query_foaf_balances(payload, plugin):
-    # TODO: parse from payload
-    amt_to_rebalance = 150000
-    # TODO: parse from payload but 1 means Outgoing forwarding
-    flow_value = 0
-
-    if flow_value == 0:
+def handle_query_foaf_balances(flow_value, amt_to_rebalance, plugin):
+    if flow_value == b'\x00':
         plugin.log("compute channels on which I want {} satoshis incoming while rebalancing".format(
             amt_to_rebalance))
-    elif flow_value == 1:
+    elif flow_value == b'\x01':
         plugin.log("compute channels on which I want to forward {} satoshis  while rebalancing".format(
             amt_to_rebalance))
 
     _, channels = get_funds(plugin)
 
     kappa, tau = helper_compute_node_parameters(channels)
-    nu = float(tau)/kappa
+    nu = float(tau) / kappa
     channels = helper_compute_channel_balance_coefficients(channels)
 
-    result = []
+    channel_ids = []
     for channel in channels:
         reserve = int(int(channel["channel_total_sat"]) * 0.01) + 1
         if flow_value == 1:
             if channel["zeta"] > nu:
                 if int(channel["channel_sat"]) > amt_to_rebalance + reserve:
-                    result.append(channel["short_channel_id"])
+                    channel_ids.append(channel["short_channel_id"])
         elif flow_value == 0:
             if channel["zeta"] < nu:
-                if int(channel["channel_total_sat"])-int(channel["channel_sat"]) > amt_to_rebalance + reserve:
-                    result.append(channel["short_channel_id"])
+                if int(channel["channel_total_sat"]) - int(channel["channel_sat"]) > amt_to_rebalance + reserve:
+                    channel_ids.append(channel["short_channel_id"])
     plugin.log("{} of {} channels are good for rebalancing {} satoshis they are: {}".format(
-        len(result), len(channels), amt_to_rebalance, ", ".join(result)))
-    return result
+        len(channel_ids), len(channels), amt_to_rebalance, ", ".join(channel_ids)))
+    return channel_ids
 
 
-def send_reply_foaf_balances(peer, channels, plugin):
+def send_reply_foaf_balances(peer, amt, channels, plugin):
+    encode_reply_foaf_balances(channels, amt, plugin)
+
     # TODO: CHECK if 107b is the correct little endian of 439
-    plugin.rpc.dev_sendcustommsg(peer, "107b123412341234")
-    return
+    res = plugin.rpc.dev_sendcustommsg(peer, "107b123412341234")
+    plugin.log("Sent query_foaf_balances message to {peer_id}. Response: {res}".format(
+        peer_id=peer,
+        res=res
+    ))
+    reply = {"peer_id": peer, "response": res}
+    return reply
 
 
 @plugin.hook('peer_connected')
@@ -209,6 +278,7 @@ def on_connected(plugin, **kwargs):
 
 @plugin.hook('custommsg')
 def on_custommsg(peer_id, message, plugin, **kwargs):
+    global BTC_CHAIN_HASH
     plugin.log("Got a custom message {msg} from peer {peer_id}".format(
         msg=message,
         peer_id=peer_id
@@ -218,19 +288,25 @@ def on_custommsg(peer_id, message, plugin, **kwargs):
     # remove prefix:
     message = message[8:]
     message_type = get_message_type(message)
-    message_payload = get_message_payload(message)
+    # message_payload = get_message_payload(message)
 
     # query_foaf_balances message has type 437 which is 01b5 in hex
+    return_value = {}
     if message_type == QUERY_FOAF_BALANCES:
         plugin.log("received query_foaf_balances message")
-        result = handle_query_foaf_balances(message_payload, plugin)
-        send_reply_foaf_balances(peer_id, result, plugin)
+        _, chain_hash, flow, amt = decode_query_foaf_balances(message)
+
+        if chain_hash == BTC_CHAIN_HASH:
+            result = handle_query_foaf_balances(flow, amt, plugin)
+            r = send_reply_foaf_balances(peer_id, amt, result, plugin)
+            return_value = {"result": r}
+        else:
+            plugin.log("not handling non bitcoin chains for now")
 
-    if message_type == REPLY_FOAF_BALANCES:
+    elif message_type == REPLY_FOAF_BALANCES:
         plugin.log("received a reply_foaf_balances message")
-    plugin.log(message)
-    plugin.log(str(type(message)))
-    return {'result': 'continue'}
+
+    return return_value
 
 
 @plugin.init()