connect.py

import sys

from web3 import Web3

from console import print_error, print_info


class Connect:
    __instance = None

    @staticmethod
    def get_instance():
        if Connect.__instance == None:
            Connect()
        return Connect.__instance

    def __init__(self):
        if Connect.__instance == None:
            Connect.__instance = self
            self.variables = {}
            self.w3 = None

    def add_connection(self, values={}):
        for k, v in values.items():
            self.variables[k] = v
        self.create_connection()

    def create_connection(self):
        if self.w3 == None:
            # connection = self.variables["provider"] + \
            #     ":" + self.variables["port"]
            connection = self.variables["provider"]
            self.w3 = Web3(Web3.HTTPProvider(connection))
            if self.w3.isConnected():
                print("Connection created with Blockchain")
            else:
                print("Connection error")
                self.del_connection()
        else:
            print("Connection already exists")

    def has_connection(self):
        return self.w3 != None

    def del_connection(self):
        self.w3 = None
        self.variables = {}

    def deploy_contract(self, abi, bytecode, opcode, address, pkey):
        if self.has_connection():
            contract = self.w3.eth.contract(abi=abi, opcodes=opcode, bytecode=bytecode)
            nonce = self.w3.eth.getTransactionCount(address)
            gas_price = self.w3.eth.gas_price
            params_transaction = {
                "from": address,
                "nonce": nonce,
                "gasPrice": gas_price,
                "chainId": int(self.variables["chainid"]),
            }
            transaction = contract.constructor().build_transaction(params_transaction)
            # sign transaction
            signed = self.w3.eth.account.sign_transaction(transaction, private_key=pkey)
            hash = self.w3.eth.send_raw_transaction(signed.rawTransaction)
            receipt = self.w3.eth.wait_for_transaction_receipt(hash)
            print_info("Contract deployed!")
            print_info("Contract Address: {}".format(receipt.contractAddress))
            return receipt.contractAddress
        else:
            return {"No connection to blockchain"}

    def get_bytecode(self, address):
        if self.has_connection():
            address = Web3.toChecksumAddress(address)
            bytecode = self.w3.eth.get_code(address).hex()
            return bytecode
        else:
            print_error("No connection to blockchain")

    def get_variables(self):
        return self.variables

    def show_variables(self):
        print_info(" Connection data on Blockchain")
        print(" -----------------------------")
        flag = 0
        for key, value in self.variables.items():
            flag += 1
            if flag > 1:
                print(" |")
            sys.stdout.write(" |_")
            sys.stdout.write("%s" % key)
            sys.stdout.write(" = %s \n" % (value))
        print("")