rather get hashes in a better way

blockchain.py

@@ -1,10 +1,8 @@
-import json
 import logging
 from datetime import datetime
 from hashlib import sha256
 
-from database import Block, db, DateTimeEncoder
-from helpers import json_serializer
+from database import Block, db
 
 
 logger = logging.getLogger('root.blockchain')
@@ -72,9 +70,11 @@ class Blockchain:
         last_block = self.last_block
 
         return {
+            'height': last_block.height + 1 if last_block else 0,
+            'timestamp': datetime.utcnow(),
             'transactions': self.current_transactions,
             'previous_hash': last_block.hash if last_block else 0,
-            'timestamp': datetime.now()
+            'proof': -1,
         }
 
     def save_block(self, block_dict):
@@ -118,9 +118,14 @@ class Blockchain:
         return db.query(Block).order_by(Block.height.desc()).first()
 
     @staticmethod
-    def hash(block):
+    def hash(b):
         """
         Creates a SHA-256 hash of the fields for a Block
         """
-        json_string = json.dumps(block, sort_keys=True, cls=DateTimeEncoder)
-        return sha256(json_string.encode()).hexdigest()
+        byte_array = f"{b['height']}" \
+                     f"{b['timestamp']}" \
+                     f"{b['transactions']}" \
+                     f"{b['previous_hash']}" \
+                     f"{b['proof']}".encode()
+
+        return sha256(byte_array).hexdigest()

database.py

@@ -53,7 +53,7 @@ class Peer(BaseModel):
 
 
 class Block(BaseModel):
-    height = Column(Integer, primary_key=True, autoincrement=True)
+    height = Column(Integer, primary_key=True)
     timestamp = Column(DateTime, index=True)
     transactions = Column(PickleType)
     previous_hash = Column(String(64))

mining.py

@@ -20,7 +20,7 @@ def proof_of_work(current_block, difficulty, event):
     # String of 64 f's replaced with 3 leading zeros (if the difficulty is 3): 000fff...f
     target = str.ljust("0" * difficulty, 64, "f")
 
-    current_block['timestamp'] = datetime.now()
+    current_block['timestamp'] = datetime.utcnow()
     current_block['proof'] = 0
     guess_hash = Blockchain.hash(current_block)
 
@@ -28,7 +28,7 @@ def proof_of_work(current_block, difficulty, event):
         # Check if we should still be mining
         # if not event.is_set():
         #     raise Exception("STOP MINING")
-        current_block['timestamp'] = datetime.now()
+        current_block['timestamp'] = datetime.utcnow()
         current_block['proof'] += 1
         guess_hash = Blockchain.hash(current_block)