以太坊研究系列【合约进阶】

chaimyu(58)

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此文档为个人整理学习使用，部分内容来源于网络，也期待能给你带来益处。

怎么进阶

以太坊的机制、基本合约都已经看过了，怎么再进一步做一个线上的合约呢？把以下内容都看一遍，不进阶都难吧！

solidity不懂就查
http://solidity.readthedocs.io/en/develop/index.html

solidity中文，聊胜于无
http://blog.csdn.net/xiatiancc/article/details/78910374

创建TOKEN示例
https://www.ethereum.org/token

https://www.ethereum.org/dao#the-shareholder-association

ROLL应用
https://etheroll.com/#tab7

这破链接也太长了，就看了内容还可以，有些代码不能用了
https://m.baidu.com/from=2001a/bd_page_type=1/ssid=8b88636861696d7975a926/uid=0/pu=usm%25401%252Csz%25401320_2003%252Cta%2540iphone_1_11.2_1_11.8/baiduid=721D44D93DB7C7ABC252E5F719E759BF/w=0_10_/t=iphone/l=3/tc?ref=www_iphone&lid=11854519200286667363&order=9&fm=alop&tj=www_normal_9_0_10_title&vit=osres&m=8&srd=1&cltj=cloud_title&asres=1&title=%25E5%25B8%25B8%25E8%25A7%2581%25E9%2597%25AE%25E9%25A2%2598-Solidity%25E5%25AE%2598%25E6%2596%25B9%25E6%2596%2587%25E6%25A1%25A3%25E4%25B8%25AD%25E6%2596%2587%25E7%2589%2588-%25E6%259E%2581%25E5%25AE%25A2%25E5%25AD%25A6%25E9%2599%25A2Wiki&dict=32&w_qd=IlPT2AEptyoA_yimI5uoHyogtcLKMrGyHxiWrO_4dxZ1&tcplug=1&sec=26871&di=010b5b85f9014684&bdenc=1&tch=124.915.59.1906.7.95402026&nsrc=IlPT2AEptyoA_yixCFOxXnANedT62v3IERuKLGBO_zGrlViyceXeHhhdXTqqAp7GEUbzwWGKxBt8gyf8RjJvnNlWdvR6sVttmSicsKmmxsnHE1NOt2Y5Nc4XTT1wy345nrVysQch&eqid=a483b6679c227000100000035a5a20c8&wd=&clk_

web3js调用执行不成功

帐号信息如下：

account1:0x54b865714068f5f03574ace39a1f3279c4e83e2c
account2:0x469f07278600b1cb031448fd25f187f24a89ecb6
account3:0x068a7a0022a0e20d78682f39aa75547a0a260a2a
contract addr:0xF4eAF74F94c84D8195Ee73BB0015e4855722731b

重新用https://www.ethereum.org/token此处完整例子部署合约，设置88个珍惜标志，小数位数为0

先在mist设置好买价格为5Ether，卖为0Ether，在web3js中调用buy，调用成果但一直没法真正买成功，输出如下：

confirmation: 0
receipt: { blockHash: '0x3d9657b5f9c6d687bf21d1958a0d1affb236e4b87ed0f0970514183557094b1e',
  blockNumber: 8470,
  contractAddress: null,
  cumulativeGasUsed: 90000,
  from: '0x54b865714068f5f03574ace39a1f3279c4e83e2c',
  gasUsed: 90000,
  logsBloom: '...',
  root: '0x9eaf64c3d9946e4a29a6d8df176447c994cd9f53ad77ec108313d78b909a457f',
  to: '0xf4eaf74f94c84d8195ee73bb0015e4855722731b',
  transactionHash: '0x1a244972a4cf03b747334ec77ba50a8b0bdf1457b4d2724d157cddd489b2e714',
  transactionIndex: 0,
  events: {} }

开始以为是参数设置问题，调整几次也没用，其实从输出可以看出是从account1到contract addr，再次查询buy代码：

/// @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
}

没有收到Transfer事件，也就是说这个过程可能出错了，_transfer中第一个参数是this，这个是合约地址，也就是说需要从合约地址转代币“GF88”到account1，而刚才建立代币“GF88”时是用account3建立的，合约地址上并没有这种代币！

从mist转了37个代币“GF88”到合约地址，再次调用web3js，这次成功了！成功输出如下：

receipt: { blockHash: '0x68019fe35bda68b5e1ab26d1de239d203b470828f05f5429ff9cde94ed4eae7c',
  blockNumber: 8513,
  contractAddress: null,
  cumulativeGasUsed: 36009,
  from: '0x54b865714068f5f03574ace39a1f3279c4e83e2c',
  gasUsed: 36009,
  logsBloom: '...',
  root: '0x81523d3f9cc640c80b3b97339c0caa06a075adbd91621cdc16983badca10f3bc',
  to: '0xf4eaf74f94c84d8195ee73bb0015e4855722731b',
  transactionHash: '0x076c89af087d4589bdc1c1a579c214252434b8b057ec617e93b7009ddfd46b32',
  transactionIndex: 0,
  events: 
   { Transfer: 
      { address: '0xF4eAF74F94c84D8195Ee73BB0015e4855722731b',
        blockNumber: 8513,
        transactionHash: '0x076c89af087d4589bdc1c1a579c214252434b8b057ec617e93b7009ddfd46b32',
        transactionIndex: 0,
        blockHash: '0x68019fe35bda68b5e1ab26d1de239d203b470828f05f5429ff9cde94ed4eae7c',
        logIndex: 0,
        removed: false,
        id: 'log_6b233e6a',
        returnValues: [Object],
        event: 'Transfer',
        signature: '0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef',
        raw: [Object] } } }

web3js调用代码如下：

contract.methods.buy().send({from: "0x54b865714068f5f03574ace39a1f3279c4e83e2c", value:web3.utils.toWei("10")})
.on('transactionHash', function(hash){
    console.log("transactionHash:", hash);
})
.on('confirmation', function(confirmationNumber, receipt){
    console.log("confirmation:", confirmationNumber);
})
.on('receipt', function(receipt){
    // receipt example
    console.log("receipt:", receipt); //查询这里可以得到结果
})
.on('error', console.error); // If a out of gas error, the second parameter is the receipt.

合约编译和执行错误

function要求使用view声明

solidity某版本要求用view或pure，view为只读不改，pure为不读不改，类似math函数
调用方法时报gas不够

试了多次，如果被执行函数中require条件不满足则直接提示此错误，当把条件改成满足后则可以调用执行！难道调用前先在本地做过一次计算，发现条件不满足？

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