From 44368863719d36ba2ad6925c5ea3cdb9a8dcc2cb Mon Sep 17 00:00:00 2001
From: zixuanzh <zixuanzh@seas.upenn.edu>
Date: Thu, 25 Apr 2019 13:25:09 -0400
Subject: [PATCH] implement add get providers

---
 libp2p/kademlia/protocol.py | 50 ++++++++++++++++++++++++++++++++-----
 libp2p/kademlia/utils.py    |  4 +++
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/libp2p/kademlia/protocol.py b/libp2p/kademlia/protocol.py
index b0eea2b..0090c64 100644
--- a/libp2p/kademlia/protocol.py
+++ b/libp2p/kademlia/protocol.py
@@ -5,6 +5,7 @@ import logging
 from rpcudp.protocol import RPCProtocol
 from .kad_peerinfo import create_kad_peerinfo
 from .routing import RoutingTable
+from .utils import validate_provider_id
 
 
 log = logging.getLogger(__name__)  # pylint: disable=invalid-name
@@ -36,12 +37,6 @@ class KademliaProtocol(RPCProtocol):
             ids.append(rid)
         return ids
 
-    def rpc_add_provider(self, sender, nodeid, key):
-        pass
-
-    def rpc_get_providers(self, sender, nodeid, key):
-        pass
-
     def rpc_stun(self, sender):  # pylint: disable=no-self-use
         return sender
 
@@ -79,6 +74,38 @@ class KademliaProtocol(RPCProtocol):
             return self.rpc_find_node(sender, nodeid, key)
         return {'value': value}
 
+    def rpc_add_provider(self, sender, nodeid, key, provider_peerinfo):
+        """
+        rpc when receiving an add_provider call
+        should validate received PeerInfo matches sender nodeid
+        if it does, receipient must store a record in its datastore
+        """
+        log.info("adding provider for key %s in local table",
+                 str(key))
+        if validate_provider_id(nodeid, provider_peerinfo):
+            source = create_kad_peerinfo(nodeid, sender[0], sender[1])
+            # TODO differentiate this from key, value
+            self.storage[key] = provider_peerinfo
+            return True
+        return False
+
+    def rpc_get_providers(self, sender, key):
+        """
+        rpc when receiving a get_providers call
+        should look up key in data store and respond with records
+        plus a list of closer peers in itrs routing table
+        """
+        providers = []
+        record = self.storage.get(key, None)
+        if record:
+            providers.append(record)
+
+        keynode = create_kad_peerinfo(key)
+        neighbors = self.router.find_neighbors(keynode)
+        providers.extend(neighbors)
+
+        return providers
+
     async def call_find_node(self, node_to_ask, node_to_find):
         address = (node_to_ask.ip, node_to_ask.port)
         result = await self.find_node(address, self.source_node.peer_id,
@@ -101,6 +128,17 @@ class KademliaProtocol(RPCProtocol):
         result = await self.store(address, self.source_node.peer_id, key, value)
         return self.handle_call_response(result, node_to_ask)
 
+    def call_add_provider(self, node_to_ask, key):
+        address = (node_to_ask.ip, node_to_ask.port)
+        result = await self.add_provider(address,
+                                         self.source_node.peer_id, key)
+        return self.handle_call_response(result, node_to_ask)
+
+    def call_get_providers(self, node_to_ask, key):
+        address = (node_to_ask.ip, node_to_ask.port)
+        result = await self.get_providers(address, key)
+        return self.handle_call_response(result, node_to_ask)
+
     def welcome_if_new(self, node):
         """
         Given a new node, send it all the keys/values it should be storing,
diff --git a/libp2p/kademlia/utils.py b/libp2p/kademlia/utils.py
index da90085..d47e4e0 100644
--- a/libp2p/kademlia/utils.py
+++ b/libp2p/kademlia/utils.py
@@ -55,3 +55,7 @@ def shared_prefix(args):
 def bytes_to_bit_string(bites):
     bits = [bin(bite)[2:].rjust(8, '0') for bite in bites]
     return "".join(bits)
+
+
+def validate_provider_id(sender_id, sender_peerinfo):
+    return sender_id == sender_peerinfo.peer_id