Store transactions in Firebase DB, removed usage of nacl.encoding

 - Using bytes.from_hex and bytes.hex instead of nacl.encoding since it is
   planned to be made deprecated
   (pyca/pynacl#532)
 - Unconfirmed transactions are now stored in the firebase realtime database
   since using in-memory variables in cloud run does not guarantee safety.

blockchain.py

@@ -15,6 +15,7 @@
 from google.cloud import firestore
 import firebase_admin as firebase
 import firebase_admin.db as firebase_db
+from flask_cors import CORS
 
 import encryption
 
@@ -57,6 +58,7 @@ def verify_transaction(self):
         <sender_public_key receiver_public_key message>
         """
         if self.signature is None:
+            print("No signature")
             return False
         try:
             sender_key = encryption.decode_verify_key(self.sender)
@@ -395,6 +397,7 @@ def parse_node_addr(addr):
 
 # Instantiate the Node
 app = Flask(__name__)
+CORS(app)
 
 # custom JSONEncoder for our custom classes
 class BlockchatJSONEncoder(JSONEncoder):
@@ -424,7 +427,7 @@ def custom_obj_hook(self, dct):
 node_url = os.getenv("NODE_ADDR", None)
 assert node_url is not None
 node_url = parse_node_addr(node_url)
-node_identifier = encryption.encode_verify_key(node_secret.verify_key).decode()
+node_identifier = encryption.encode_verify_key(node_secret.verify_key)
 
 db = firestore.Client.from_service_account_json("./firebase-adminsdk.json")
 blockchain_c = db.collection("blockchain")

encryption.py

@@ -1,4 +1,3 @@
-import nacl.encoding
 import nacl.signing
 import nacl.exceptions
 import nacl.utils
@@ -19,13 +18,13 @@ def generate_signing_key() -> (nacl.signing.VerifyKey, nacl.signing.SigningKey):
 
     return verify_key, signing_key
 
-def encode_verify_key(verify_key: nacl.signing.VerifyKey) -> bytes:
+def encode_verify_key(verify_key: nacl.signing.VerifyKey) -> str:
     """Encodes given verify_key into a bytes object"""
-    return verify_key.encode(encoder=nacl.encoding.HexEncoder)
+    return verify_key.encode().hex()
 
-def decode_verify_key(verify_key_hex: bytes) -> nacl.signing.VerifyKey:
+def decode_verify_key(verify_key_hex: str) -> nacl.signing.VerifyKey:
     """Decodes given verify_key_hex into a verify_key"""
-    return nacl.signing.VerifyKey(verify_key_hex, encoder=nacl.encoding.HexEncoder)
+    return nacl.signing.VerifyKey(bytes.fromhex(verify_key_hex))
 
 def sign_message(signing_key: nacl.signing.SigningKey, message):
     """Signs message using signing_key"""

requirements.txt

@@ -4,3 +4,4 @@ PyNaCl==1.3.0
 gunicorn==20.0.4
 google-cloud-firestore==1.7.0
 firebase-admin==4.3.0
+flask-cors==3.0.8