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文/Mr. Neo Chan, 陈景峯
本文节选自电子书《Netkiller Blockchain 手札》
中国广东省深圳市龙华新区民治街道溪山美地
518131
+86 13113668890
<netkiller@msn.com>
文档始创于2018-02-10
版权 © 2018 Netkiller(Neo Chan). All rights reserved.
版权声明
内容摘要
这一部关于区块链开发及运维的电子书。
为什么会写区块链电子书?因为2018年是区块链年。
这本电子书是否会出版(纸质图书)? 不会,因为互联网技术更迭太快,纸质书籍的内容无法实时更新,一本书动辄百元,很快就成为垃圾,你会发现目前市面的上区块链书籍至少是一年前写的,内容已经过时,很多例子无法正确运行。所以我不会出版,电子书的内容会追逐技术发展,及时跟进软件版本的升级,做到内容最新,至少是主流。
这本电子书与其他区块链书籍有什么不同?市面上大部分区块链书籍都是用2/3去讲区块链原理,只要不到 1/3 的干货,干货不够理论来凑,通篇将理论或是大谈特谈区块链行业,这些内容更多是头脑风暴,展望区块链,均无法落地实施。本书与那些书籍完全不同,不讲理论和原理,面向应用落地,注重例子,均是干货。
电子书更新频率?每天都会有新内容加入,更新频率最迟不会超过一周,更新内容请关注 https://github.com/netkiller/netkiller.github.io/commits/master
本文采用碎片化写作,原文会不定期更新,请尽量阅读原文。
http://www.netkiller.cn/blockchain/index.html
您的打赏是我的写作动力:http://www.netkiller.cn/blockchain/donations.html
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33.4. 游戏领域区块链探索
如何将区块链嫁接到游戏领域,我做了很多思考,经过分析总结,发现下面几项内容非常适合上链。
上链内容
如果说区块链应用于游戏领域,可能99%的人首先会想到是代币,的确游戏领域实施区块链连,代币必不可少。但是区块链不等于代币。
下面我们要思考为什么需要将游戏数据放到区块链上,玩游戏的人都知道私服,私人架设游戏服务器,私服上玩游戏遇到最大的问题就是公平性。管理员可以随意调整服务器参数。
私服存在哪些问题呢?
- 修改游戏装备属性
- 修改生命与魔法值
- 关卡参数
- 人物属性
- 随意封账号
这是我们在私服上遇到的最大问题,那么官方服务器就公平吗?不一定,对于弱势的玩家只能相信游戏公司的承诺。
有了区块链技术,我们能做什么呢?例如我们将用户装备数据等数据上链,这样保证了装备永远属于玩家
区块链能做什么?
- “点” 奖励采用代币实现,可以实现流通,兑换,消费等等......
- 爆出装备立即上链
- 用户等级属性上链
- 用户状态上链
- 关卡数据上链
凸显公平性,我们采用公链,查询用户数据可以使用接口,也可以直接到公链上查询。
下面详细讲解具体怎么实现。
33.4.1. 游戏代币
传统币 Point (点) 仅仅是一个数字,数字存在数据库中,例如
- Username | Point (Integer)
- -----------------------
- Neo | 1000
- Jam | 500
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因为仅仅是一个数字,管理员可以随意修改,黑客也可随意修改,例如
- update member set point = 1000000000000 where username = 'Neo'
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瞬间就有 1000000000000 点。由于是在数据库中修改,没有日志,不知道谁操作的,可能是开发人员,可以是管理员,也可能是黑客。
如何消费“点呢”,例如消费 100 个点:
- update member set point = point - 100 where username = 'Neo'
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传统币“点”,只是一个数字做加法和减法运算,安全性主要依赖于开发团队的能(期望别出BUG),运维团队的能力(被别黑客攻击),以及DBA(数据库管理员)的节操。
审计全靠开发人员打印出的日志。
现在我们再看看数字货币,跟很多朋友聊天中发现,他们还没有理解什么是币,他们认为数字代币花掉就没了(消失了),然后通过挖矿不停的产生新币,这种理解完全错误。
数字币是这样运作的,首先发行时设置了币的总量例如 1000000,然后将所有代币存入发行者账号,例如 account 1
- account | coin
- ---------------------------------
- account1 | 1000000
- account2 | 0
- account3 | 0
- account4 | 0
- account5 | 0
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现在 account2 游戏在线1小时奖励 10 个币,系统从账号account1转账5个币给 account2
- account | coin
- ---------------------------------
- account1 | 999990
- account2 | 10
- account3 | 0
- account4 | 0
- account5 | 0
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以此类推,从 account1 转账给其他账号。
- account | coin
- ---------------------------------
- account1 | 999960
- account2 | 10
- account3 | 10
- account4 | 10
- account5 | 10
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现在 account3 消费 5个币买了装备。从 account3 转 5 个币到 account1
- account | coin
- ---------------------------------
- account1 | 999965
- account2 | 10
- account3 | 5
- account4 | 10
- account5 | 10
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现在你应该看懂了把,代币是流通的,总量是不变的。account1 账号负责币的发行,回收等等工作。
同时任何转账将产生区块,历史数据永久记录。
下面是一个高级代币合约,地址https://github.com/ibook/NetkillerAdvancedToken
- pragma solidity ^0.4.20;
- /******************************************/
- /* Netkiller ADVANCED TOKEN */
- /******************************************/
- /* Author netkiller <netkiller@msn.com> */
- /* Home http://www.netkiller.cn */
- /* Version 2018-03-05 */
- /* Version 2018-03-06 - Add Global lock */
- /******************************************/
- interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) public; }
- contract NetkillerAdvancedToken {
- address public owner;
- // Public variables of the token
- string public name;
- string public symbol;
- uint8 public decimals = 2;
- // 18 decimals is the strongly suggested default, avoid changing it
- uint256 public totalSupply;
-
- uint256 public sellPrice;
- uint256 public buyPrice;
- // This creates an array with all balances
- mapping (address => uint256) public balanceOf;
- mapping (address => mapping (address => uint256)) public allowance;
- // This generates a public event on the blockchain that will notify clients
- event Transfer(address indexed from, address indexed to, uint256 value);
- // This notifies clients about the amount burnt
- event Burn(address indexed from, uint256 value);
- event Approval(address indexed owner, address indexed spender, uint256 value);
-
- mapping (address => bool) public frozenAccount;
- /* This generates a public event on the blockchain that will notify clients */
- event FrozenFunds(address target, bool frozen);
- bool lock = true;
- /**
- * Constrctor function
- *
- * Initializes contract with initial supply tokens to the creator of the contract
- */
- function NetkillerAdvancedToken(
- uint256 initialSupply,
- string tokenName,
- string tokenSymbol
- ) public {
- owner = msg.sender;
- totalSupply = initialSupply * 10 ** uint256(decimals); // Update total supply with the decimal amount
- balanceOf[msg.sender] = totalSupply; // Give the creator all initial tokens
- name = tokenName; // Set the name for display purposes
- symbol = tokenSymbol; // Set the symbol for display purposes
- }
- modifier onlyOwner {
- require(msg.sender == owner);
- _;
- }
- modifier isLock {
- require(!lock);
- _;
- }
-
- function setLock(bool _lock) onlyOwner {
- lock = _lock;
- }
- function transferOwnership(address newOwner) onlyOwner public {
- owner = newOwner;
- }
-
- /* Internal transfer, only can be called by this contract */
- function _transfer(address _from, address _to, uint _value) isLock internal {
- require (_to != 0x0); // Prevent transfer to 0x0 address. Use burn() instead
- require (balanceOf[_from] >= _value); // Check if the sender has enough
- require (balanceOf[_to] + _value > balanceOf[_to]); // Check for overflows
- require(!frozenAccount[_from]); // Check if sender is frozen
- require(!frozenAccount[_to]); // Check if recipient is frozen
- balanceOf[_from] -= _value; // Subtract from the sender
- balanceOf[_to] += _value; // Add the same to the recipient
- Transfer(_from, _to, _value);
- }
- /**
- * Transfer tokens
- *
- * Send `_value` tokens to `_to` from your account
- *
- * @param _to The address of the recipient
- * @param _value the amount to send
- */
- function transfer(address _to, uint256 _value) public {
- _transfer(msg.sender, _to, _value);
- }
- /**
- * Transfer tokens from other address
- *
- * Send `_value` tokens to `_to` in behalf of `_from`
- *
- * @param _from The address of the sender
- * @param _to The address of the recipient
- * @param _value the amount to send
- */
- function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
- require(_value <= allowance[_from][msg.sender]); // Check allowance
- allowance[_from][msg.sender] -= _value;
- _transfer(_from, _to, _value);
- return true;
- }
- /**
- * Set allowance for other address
- *
- * Allows `_spender` to spend no more than `_value` tokens in your behalf
- *
- * @param _spender The address authorized to spend
- * @param _value the max amount they can spend
- */
- function approve(address _spender, uint256 _value) public
- returns (bool success) {
- allowance[msg.sender][_spender] = _value;
- Approval(msg.sender, _spender, _value);
- return true;
- }
- /**
- * Set allowance for other address and notify
- *
- * Allows `_spender` to spend no more than `_value` tokens in your behalf, and then ping the contract about it
- *
- * @param _spender The address authorized to spend
- * @param _value the max amount they can spend
- * @param _extraData some extra information to send to the approved contract
- */
- function approveAndCall(address _spender, uint256 _value, bytes _extraData)
- public
- returns (bool success) {
- tokenRecipient spender = tokenRecipient(_spender);
- if (approve(_spender, _value)) {
- spender.receiveApproval(msg.sender, _value, this, _extraData);
- return true;
- }
- }
- /**
- * Destroy tokens
- *
- * Remove `_value` tokens from the system irreversibly
- *
- * @param _value the amount of money to burn
- */
- function burn(uint256 _value) onlyOwner public returns (bool success) {
- require(balanceOf[msg.sender] >= _value); // Check if the sender has enough
- balanceOf[msg.sender] -= _value; // Subtract from the sender
- totalSupply -= _value; // Updates totalSupply
- Burn(msg.sender, _value);
- return true;
- }
- /**
- * Destroy tokens from other account
- *
- * Remove `_value` tokens from the system irreversibly on behalf of `_from`.
- *
- * @param _from the address of the sender
- * @param _value the amount of money to burn
- */
- function burnFrom(address _from, uint256 _value) onlyOwner public returns (bool success) {
- require(balanceOf[_from] >= _value); // Check if the targeted balance is enough
- require(_value <= allowance[_from][msg.sender]); // Check allowance
- balanceOf[_from] -= _value; // Subtract from the targeted balance
- allowance[_from][msg.sender] -= _value; // Subtract from the sender's allowance
- totalSupply -= _value; // Update totalSupply
- Burn(_from, _value);
- return true;
- }
- /// @notice Create `mintedAmount` tokens and send it to `target`
- /// @param target Address to receive the tokens
- /// @param mintedAmount the amount of tokens it will receive
- function mintToken(address target, uint256 mintedAmount) onlyOwner public {
- balanceOf[target] += mintedAmount;
- totalSupply += mintedAmount;
- Transfer(0, this, mintedAmount);
- Transfer(this, target, mintedAmount);
- }
- /// @notice `freeze? Prevent | Allow` `target` from sending & receiving tokens
- /// @param target Address to be frozen
- /// @param freeze either to freeze it or not
- function freezeAccount(address target, bool freeze) onlyOwner public {
- frozenAccount[target] = freeze;
- FrozenFunds(target, freeze);
- }
- /// @notice Allow users to buy tokens for `newBuyPrice` eth and sell tokens for `newSellPrice` eth
- /// @param newSellPrice Price the users can sell to the contract
- /// @param newBuyPrice Price users can buy from the contract
- function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner public {
- sellPrice = newSellPrice;
- buyPrice = newBuyPrice;
- }
- /// @notice Buy tokens from contract by sending ether
- function buy() payable public {
- uint amount = msg.value / buyPrice; // calculates the amount
- _transfer(this, msg.sender, amount); // makes the transfers
- }
- /// @notice Sell `amount` tokens to contract
- /// @param amount amount of tokens to be sold
- function sell(uint256 amount) public {
- require(this.balance >= amount * sellPrice); // checks if the contract has enough ether to buy
- _transfer(msg.sender, this, amount); // makes the transfers
- msg.sender.transfer(amount * sellPrice); // sends ether to the seller. It's important to do this last to avoid recursion attacks
- }
-
- function transfer(address _to, uint256 _value, bytes _data) public returns (bool) {
- require(_to != address(this));
- transfer(_to, _value);
- require(_to.call(_data));
- return true;
- }
- function transferFrom(address _from, address _to, uint256 _value, bytes _data) public returns (bool) {
- require(_to != address(this));
- transferFrom(_from, _to, _value);
- require(_to.call(_data));
- return true;
- }
- function approve(address _spender, uint256 _value, bytes _data) public returns (bool) {
- require(_spender != address(this));
- approve(_spender, _value);
- require(_spender.call(_data));
- return true;
- }
-
- }
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这个代币合约实现了,增发,减持,全局锁,账号冻结/解冻 等等功能。
33.4.2. 玩家属性与游戏装备
下面的合约实现了游戏玩家上链,上链信息有玩家属性,例如肤色,眼睛,头发,血统等等。身上的穿戴物品包括武器等等。
- pragma solidity ^0.4.20;
- contract Player {
- address public owner;
-
- string name;
- bool lock = false; //合约锁
- uint number = 1;
- uint attr_number = 1;
-
- mapping (address => string) guestbook; //客户留言本
- struct Attribute {
- string key; // 属性的名字
- string value; // 属性值
-
- }
- mapping (uint => Attribute) attribute;
- struct Wear {
- string name; // 装备名
- string desciption; // 信息
- string attribute; // 属性,存储json 数据。例如生命+10,魔法+5,冰冻系...
- }
- mapping (uint => Wear) wear;
-
- function Player(string _name) public {
- name = _name;
- }
-
- modifier onlyOwner {
- require(msg.sender == owner);
- _;
- }
-
- // 名称
- function getName() public view returns(string){
- return name;
- }
- function setLock(bool _lock) onlyOwner public {
- lock = _lock;
- }
- // 增加人物属性,例如肤色,眼睛,头发等等
- function putAttribute(string _key, string _value) onlyOwner public{
- if(lock == false){
- Attribute memory item = Attribute(_key, _value);
- attribute[attr_number] = item;
- attr_number = attr_number + 1;
- }
- }
- // 获得属性
- function getAttribute(uint _attr_number) public view returns(string, string) {
- require(_attr_number < attr_number);
- Attribute memory item = attribute[_attr_number];
-
- return (item.key, item.value);
- }
-
- // 增加装备信息,穿戴物品,武器,
- function putWear(string _name, string _description, string _attribute ) onlyOwner public{
- if(lock == false){
- Wear memory node = Wear(_name,_description,_attribute);
- wear[number] = node;
- number = number + 1;
- lock = true;
- }
- }
- // 获得信息
- function getWear(uint _number) public view returns(string, string, string) {
- require(_number < number);
- Wear memory item = wear[_number];
-
- return (item.name, item.desciption, item.attribute);
- }
-
- // 数量
- function getWearCount() public view returns(uint){
- return number;
- }
-
- // 客户留言
- function addGuestbook(address _owner, string message) onlyOwner public{
- guestbook[_owner] = message;
- }
- }
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33.4.3. 物品合成计算
区块链还可用于物品合成计算或者叫炼金术等等
很早的时候玩《暗黑破坏神III》 里面已一个盒子,放入符文,可以根据公式合成其他属性的符文,我任务这个需求可以使用区块链来完成。
另外在我玩XBOX游戏《巫师3》 中的炼金术,铸造,药水合成等等,我逗人都可以使用区块链完成。
33.4.4. 实施步骤
如果着手一个游戏项目上链,我们需要怎么做呢?
上链步骤
- 收集需求,收集公司的内部上链需求,听取所有部门的建议和诉求。
收集内容例如,代币发行量多少?代币小数位数,代币名称,是否会增发,是否需要冻结,代币怎样流通,怎样回收
Dapp 的 UI 设计,各种功能流程
- 分析需求,因为需求来自各种部门,各种岗位等等,他们不一定从事需求分析工作,所以我们需求对他们的需求过滤,分析,然后给出初步的PRD文档(产品需求文档)
- 根据收集的需求设计合约
根据需求设计Dapp
系统架构设计,软件架构设计,技术选型;需要考虑扩展性,灵活性,并发设计,数据安全,部署,后期监控,各种埋点(统计、监控)
- 准备环境,我们需要三个环境,开发,测试,生产(运营)。
- 项目启动
运维部门准备环境
开发部门开发合约和Dapp
测试部门准备测试用例,测试环境
Alpha 阶段,将合约部署到测试环境,测试合约的每个函数的工作逻辑,确保无误。因为合约一旦部署将不能更改,只能废弃使用新的合约,所以这个测试步骤必须重视。
Beta 阶段,将测试合约部署到测试网,例如 Ropsten ,可以邀请公司内部测试
部署合约,将合约部署到主网
Dapp 部署到生产环境。
原文地址:https://cloud.tencent.com/developer/article/1053033
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