# couchdb.yaml
version: '2'
services:
  couchdb:
    image: hyperledger/fabric-couchdb
    ports:
    - 5984:5984

    # class Block
    def serialize(self):
        return {
            "magic_no": self._magic_no,
            "block_header": self._block_header.serialize(),
            "transactions": self._transactions
        }

    # class BlockHeader
    def serialize(self):
        return self.__dict__

# class Block
    @classmethod
    def deserialize(cls, data):
        block_header_dict = data['block_header']
        block_header = BlockHeader.deserialize(block_header_dict)
        transactions = data["transactions"]
        return cls(block_header, transactions)

# class BlockHeader
    @classmethod
    def deserialize(cls, data):
        timestamp = data.get('timestamp', '')
        prev_block_hash = data.get('pre_block_hash', '')
        # hash = data.get('hash', '')
        hash_merkle_root = data.get('hash_merkle_root', '')
        height = data.get('height', '')
        nonce = data.get('nonce', '')
        block_header = cls(hash_merkle_root, height, prev_block_hash)
        block_header.timestamp = timestamp
        block_header.nonce = nonce
        return block_header

# class BlockChain:
    def new_genesis_block(self):
        if 'l' not in self.db:
            genesis_block = Block.new_genesis_block('genesis_block')
            genesis_block.set_header_hash()
            self.db.create(genesis_block.block_header.hash, genesis_block.serialize())
            self.set_last_hash(genesis_block.block_header.hash)

    def add_block(self, transactions):
        """
        add a block to block_chain
        """
        last_block = self.get_last_block()
        prev_hash = last_block.get_header_hash()
        height = last_block.block_header.height + 1
        block_header = BlockHeader('', height, prev_hash)
        block = Block(block_header, transactions)
        block.mine()
        block.set_header_hash()
        self.db.create(block.block_header.hash, block.serialize())
        last_hash = block.block_header.hash
        self.set_last_hash(last_hash)

class DB(Singleton):
    def __init__(self, db_server_url, db_name='block_chain'):
        self._db_server_url = db_server_url
        self._server = couchdb.Server(self._db_server_url)
        self._db_name = db_name
        self._db = None
    @property
    def db(self):
        if not self._db:
            try:
                self._db = self._server[self._db_name]
            except couchdb.ResourceNotFound:
                self._db = self._server.create(self._db_name)
        return self._db
    def create(self, id, data):
        self.db[id] = data
        return id
    def __getattr__(self, name):
        return getattr(self.db, name)
    def __contains__(self, name):
        return self.db.__contains__(name)
    def __getitem__(self, key):
        return self.db[key]
    def __setitem__(self, key, value):
        self.db[key] = value

# class BlockChain(object):
    def __getitem__(self, index):
        last_block = self.get_last_block()
        height = last_block.block_header.height
        if index <= height:
            return self.get_block_by_height(index)
        else:
            raise IndexError('Index is out of range')

# class BlockChain(object):
    def get_block_by_height(self, height):
        """
        Get a block by height
        """
        query = {"selector": {"block_header": {"height": height}}}
        docs = self.db.find(query)
        block = Block(None, None)
        for doc in docs:
            block.deserialize(doc)
            break
        return block

def new_parser():
    parser = argparse.ArgumentParser()
    sub_parser = parser.add_subparsers(help='commands')
    # A print command
    print_parser = sub_parser.add_parser(
        'print', help='Print all the blocks of the blockchain')
    print_parser.add_argument('--print', dest='print', action='store_true')
    # A add command
    add_parser = sub_parser.add_parser(
        'addblock', help='Print all the blocks of the blockchain')
    add_parser.add_argument(
        '--data', type=str, dest='add_data', help='block data')
    return parser
def print_chain(bc):
    for block in bc:
        print(block)
def add_block(bc, data):
    bc.add_block(data)
    print("Success!")
def main():
    parser = new_parser()
    args = parser.parse_args()
    bc = BlockChain()
    if hasattr(args, 'print'):
        print_chain(bc)
    if hasattr(args, 'add_data'):
        add_block(bc, args.add_data)
if __name__ == "__main__":
    main()

# 創(chuàng)世塊創(chuàng)建
$python3 main.py
Mining a new block
Found nonce == 19ash_hex == 047f213bcb01f1ffbcdfafad57ffeead0e86924cf439594020da47ff2508291c
<Document 'l'@'191-2f44a1493638684d9e000d8dd105192a' {'hash': 'e4f7adac65bcbb304af21be52a1b52bb28c0205a3746d63453d9e8c182de927a'}>
Mining a new block
Found nonce == 1ash_hex == 0df1ac18c84a8e524d6fe49cb04aae9af02dd85addc4ab21ac13f9d0d7ffe769
<Document 'l'@'192-168ff7ea493ca53c66690985deb5b7ac' {'hash': '01015004e21d394b1a6574eb81896e1c800f18aa22997e96b79bca22f7821a67'}>
Block(_block_header=BlockHeader(timestamp='1551317137.2814202', hash_merkle_root='', prev_block_hash='', hash='f20f3c74c831d03aaa2291af23e607896a61809b5ced222483b46795a456a1c5', nonce=None, height=0))
Block(_block_header=BlockHeader(timestamp='1551317137.358466', hash_merkle_root='', prev_block_hash='f20f3c74c831d03aaa2291af23e607896a61809b5ced222483b46795a456a1c5', hash='e4f7adac65bcbb304af21be52a1b52bb28c0205a3746d63453d9e8c182de927a', nonce=19, height=1))
Block(_block_header=BlockHeader(timestamp='1551317137.4621542', hash_merkle_root='', prev_block_hash='e4f7adac65bcbb304af21be52a1b52bb28c0205a3746d63453d9e8c182de927a', hash='01015004e21d394b1a6574eb81896e1c800f18aa22997e96b79bca22f7821a67', nonce=1, height=2))

$python3 cli.py addblock --data datas
Mining a new block
Found nonce == 6ash_hex == 0864df4bfbb2fd115eeacfe9ff4d5813754198ba261c469000c29b74a1b391c5
<Document 'l'@'193-92e02b894d09dcd64f8284f141775920' {'hash': '462ac519b6050acaa78e1be8c2c8de298b713a2e138d7139fc882f7ae58dcc88'}>
Success!