Add basic support for multiaddr addresses and improvement around peer id (#75)

* Improved peer ID construction and usage

* peer id object is directly passed to the network

no need to cast from a string to an ID

* don't base64 encode the peer id when loading from public key

* use proper multiaddr address

- keep multiaddr object into peerstore instead of string
- update network code to use new multiaddr lib
- update tests and example

* don't instanciate peerstore object in constructor

This has side effect where the same peerstore
is used for different instance of Libp2p

* add connect method to basic_host

* use zaibon's fork of sbuss/py-multiaddr

* lint

peer/id.py

@@ -1,4 +1,14 @@
 import base58
+import multihash
+
+# MaxInlineKeyLength is the maximum length a key can be for it to be inlined in
+# the peer ID.
+# * When `len(pubKey.Bytes()) <= MaxInlineKeyLength`, the peer ID is the
+#   identity multihash hash of the public key.
+# * When `len(pubKey.Bytes()) > MaxInlineKeyLength`, the peer ID is the
+#   sha2-256 multihash of the public key.
+MAX_INLINE_KEY_LENGTH = 42
+
 
 class ID:
 
@@ -15,3 +25,42 @@ class ID:
         return "<peer.ID %s*%s>" % (pid[:2], pid[len(pid)-6:])
 
     __repr__ = __str__
+
+    def __eq__(self, other):
+        #pylint: disable=protected-access
+        return self._id_str == other._id_str
+
+    def __hash__(self):
+        return hash(self._id_str)
+
+
+def id_b58_encode(peer_id):
+    """
+    return a b58-encoded string
+    """
+    #pylint: disable=protected-access
+    return base58.b58encode(peer_id._id_str).decode()
+
+
+def id_b58_decode(peer_id_str):
+    """
+    return a base58-decoded peer ID
+    """
+    return ID(base58.b58decode(peer_id_str))
+
+
+def id_from_public_key(key):
+    # export into binary format
+    key_bin = key.exportKey("DER")
+
+    algo = multihash.Func.sha2_256
+    # TODO: seems identity is not yet supported in pymultihash
+    # if len(b) <= MAX_INLINE_KEY_LENGTH:
+    #     algo multihash.func.identity
+
+    mh_digest = multihash.digest(key_bin, algo)
+    return ID(mh_digest.encode())
+
+
+def id_from_private_key(key):
+    return id_from_public_key(key.publickey())

peer/peerinfo.py

@@ -1,5 +1,42 @@
+import multiaddr
+import multiaddr.util
+from peer.id import id_b58_decode
+from peer.peerdata import PeerData
+
+
 class PeerInfo:
 	# pylint: disable=too-few-public-methods
     def __init__(self, peer_id, peer_data):
         self.peer_id = peer_id
         self.addrs = peer_data.get_addrs()
+
+
+def info_from_p2p_addr(addr):
+    if not addr:
+        raise InvalidAddrError()
+
+    parts = multiaddr.util.split(addr)
+    if not parts:
+        raise InvalidAddrError()
+
+    ipfspart = parts[-1]
+    if ipfspart.protocols()[0].code != multiaddr.protocols.P_IPFS:
+        raise InvalidAddrError()
+
+    # make sure the /ipfs value parses as a peer.ID
+    peer_id_str = ipfspart.value_for_protocol(multiaddr.protocols.P_IPFS)
+    peer_id = id_b58_decode(peer_id_str)
+
+    # we might have received just an / ipfs part, which means there's no addr.
+    if len(parts) > 1:
+        addr = multiaddr.util.join(parts[:-1])
+
+    peer_data = PeerData()
+    peer_data.addrs = [addr]
+    peer_data.protocols = [p.code for p in addr.protocols()]
+
+    return PeerInfo(peer_id, peer_data)
+
+
+class InvalidAddrError(ValueError):
+    pass

peer/peerstore.py

@@ -42,7 +42,7 @@ class PeerStore(IPeerStore):
         peer.set_protocols(protocols)
 
     def peers(self):
-        return self.peer_map.keys()
+        return list(self.peer_map.keys())
 
     def get(self, peer_id, key):
         if peer_id in self.peer_map: