简单的区块链代码入门（python演示原理和solidity 的truffle发布）实验

好久没回CSDN了
本文是几个教程的更新和融合，一部分通过python实现展示简单的区块链结构和过程，一部分用truffle发布简单的solidity智能合约脚本，算是区块链入门（不算吧。。）

python区块链模拟脚本（本地）

环境：
3.7 python
win10

import hashlib

# class Block:
#     def __init__(self, data, prev_hash):
#         self.previous_hash = prev_hash
#         self.data = data
#
#     # calculate hash
#     @property
#     def hash(self):
#         message = hashlib.sha256()
#         message.update(str(self.data).encode('utf-8'))
#         return message.hexdigest()
class Block():
    """"
    """
    def __init__(self,data,prev_hash):
        self.previous_hash = prev_hash
        self.data = data
        self.nonce = ""

    @property
    def hash(self):
        message = hashlib.sha256()
        message.update(str(self.data).encode('utf-8'))
        message.update(str(self.nonce).encode('utf-8'))
        digest = message.hexdigest()
        return digest


# first Block making function
# def create_genesis_block():
#     return Block(data="Genesis Block", prev_hash="")

def create_genesis_block():
    block = Block(data="Genesis Block",prev_hash="")
    pow = ProofOfWork(block)
    nonce, digest = pow.mine()
    print("nonce: " + str(nonce))
    print("digest: " + str(digest))
    return block

class BlockChain():
    def __init__(self):
        self.blocks = [create_genesis_block()]

    def add_block(self,data):
        prev_block = self.blocks[len(self.blocks)-1]
        block = Block(data, prev_block.hash)
        pow = ProofOfWork(block)
        nonce, digest = pow.mine()
        block.nonce = nonce
        self.blocks.append(block)

# class BlockChain():
#     """docstring for BlockChain"""
#
#     def __init__(self):
#         self.blocks = [create_genesis_block()]
#
#     def add_block(self, data):
#         prev_block = self.blocks[len(self.blocks) - 1]
#         new_block = Block(data, prev_block.hash)
#         self.blocks.append(new_block)
#         return new_block


# if __name__ == '__main__':
# 	bc = BlockChain()
#
# 	b1 = bc.add_block["jack send 0.3 btc to Alice"]
# 	b2 = bc.add_block["Alice send 0.1 btc to Tom"]
#
# 	for b in bc.blocks:
# 		print("Prev Hash:{}".format(b.previous_hash))
# 		print("Data:{}".format(b.data))
# 		print("Hash:{}".format(b.hash))
# 		print("\n")

class ProofOfWork():
    def __init__(self,block):
        self.block = block
#mining
    def mine(self):
        # 这次挖矿要让挖出的散列值开头4个0
        prefix = '0000'
        i = 0
        while True:
            nonce = str(i)
            message = hashlib.sha256()
            # 被散列化处理的内容，包括数据和nonce（随机数）
            message.update(str(self.block.data).encode('utf-8'))
            message.update(nonce.encode('utf-8'))
            digest = message.hexdigest()
            if digest.startswith(prefix):
                return nonce,digest
            i += 1





bc = BlockChain()

b1 = bc.add_block("jack send 0.3 btc to Alice")
b2 = bc.add_block("Alice send 0.1 btc to Tom")

for b in bc.blocks:
    print("Prev Hash:{}".format(b.previous_hash))
    print("Data:{}".format(b.data))
    print("Hash:{}".format(b.hash))
    print("\n")

truffle的solidity发布到ganathe模拟的以太网

Ganathe和truffle 安装和连接
安装：
参考：
https://www.cnblogs.com/hupeng1234/p/9804209.html
https://www.bilibili.com/video/BV1ds41177Cy?p=5
内容更新：
1.新建项目命令改为 truffle init（原文看到叫创建truffle就不用看了）
2.metamask （视频教程出现，检测用，已经有点老了）连接RPC网络时现在要chainId了，对应的测试链ID为1337（国内居然每一个论坛说过艹），参考连接：https://github.com/MetaMask/metamask-extension/issues/9683
truffle的使用和第一个solidity文件
参考：
https://blog.csdn.net/a394268045/article/details/79518530
这个博客基本走得通，但是版本变了脚本需要变一下（现在windows默认下载solidity本地版0.5.16，教程只有4，跑不起）
改为以下solidity脚本

pragma solidity >=0.5.6<0.7.0;

contract HelloWorld {

    constructor() public{
        
    }

  function sayHello () pure public returns(string memory) {
    return ("Hello World");
  }

  function print(string memory name) pure public returns (string memory) {
    return name;
    }
}

并且注意！！！用truffle init 命令创建的 1_initial_migration.js 文件需要改成如下：

const Migrations = artifacts.require("Migrations");
const HelloWorld = artifacts.require("HelloWorld");

module.exports = function (deployer) {
  deployer.deploy(Migrations);
  deployer.deploy(HelloWorld);
};

不要改成var和.sol，太老了已经不能用了

并且并且注意！！！！
win的参数文件只有truffle-config，其中的networks和其下的development只需要取消注销就行，参数具体如下


  networks: {
    // Useful for testing. The `development` name is special - truffle uses it by default
    // if it's defined here and no other network is specified at the command line.
    // You should run a client (like ganache-cli, geth or parity) in a separate terminal
    // tab if you use this network and you must also set the `host`, `port` and `network_id`
    // options below to some value.
    //
    development: {
     host: "127.0.0.1",     // Localhost (default: none)
     port: 7545,            // Standard Ethereum port (default: none)
     network_id: "*",       // Any network (default: none)
    },

其余的基本按照上面链接的教程即可，测试过可以跑了

以上
may the flame guide thee

来源：oschina

链接：https://my.oschina.net/u/4267218/blog/4732140

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python