区块链实战(一)实现简单的区块与区块链交易

package main
import (
  "bytes"
  "crypto/sha256"
  "time"
)
/*
1.定义一个区块的结构Block
​a.区块头：6个字段
​b.区块体：字符串表示data
*/
//区块
type Block struct {
  Version int64   //版本
  PerBlockHash []byte //前一个区块的hash值
  Hash []byte //当前区块的hash值，是为了简化代码
  MerKelRoot []byte  //梅克尔根
  TimeStamp int64  //时间抽
  Bits int64  //难度值
  Nonce int64 //随机值
//区块体
  Data []byte  //交易信息
}
/*
提供一个创建区块的方法
NewBlock(参数)
*/
func NewBlock(data string ,prevBlockHash []byte) *Block {
  var block Block
  block = Block{
    Version:      1,
    PerBlockHash: prevBlockHash,
    //Hash:         []byte{},     //区块不存储hash值，节点接受区块后独立计算并存储在本地。
    MerKelRoot:   []byte{},
    TimeStamp:    time.Now().Unix(),
    Bits:         1,
    Nonce:        1,
    Data:         []byte(data),
  }
  block.SetHash()  //填充Hash
  return &block
}
func (block *Block) SetHash() {
  // 源码里面是要传二维切片 func Join(s [][]byte, sep []byte) []byte
  tmp :=[][]byte{
    IntToByte(block.Version),
    block.PerBlockHash,
    block.MerKelRoot,
    IntToByte(block.TimeStamp),
    IntToByte(block.Bits),
    IntToByte(block.Nonce),
  }
  data:=bytes.Join(tmp,[]byte{})    //之后再计算hash
  hash := sha256.Sum256(data)
  block.Hash = hash[:]  //变切片
}
//创始块
func NewGensisBlock() *Block{
  return NewBlock("Genesis Block!",[]byte{})
}

package main
/*
1. 定义一个区块链结构BlockChain
   Block数组
*/
type BlockChain struct {
   blocks []*Block
}
/*
2. 提供一个创建BlockChain()的方法
   NewBlockChain()
*/
func NewBlockChain() *BlockChain {
   block := NewGensisBlock()
   return &BlockChain{blocks:[]*Block{block}}  //创建只有一个元素的区块链，初始化
}
/*
3. 提供一个添加区块的方法
   AddBlock(参数)
*/
func (bc *BlockChain)AddBlock(data string)  {
   PerBlockHash := bc.blocks[len(bc.blocks)-1].Hash  //这一个区块的哈希是前一块的哈希值
   block := NewBlock(data,PerBlockHash)
   bc.blocks = append(bc.blocks,block)
}

package main
import (
   "bytes"
   "encoding/binary"
   "fmt"
   "os"
)
func IntToByte(num int64) []byte {
   //func Write(w io.Writer, order ByteOrder, data interface{}) error {
   var buffer bytes.Buffer
   err := binary.Write(&buffer, binary.BigEndian, num)
   CheckErr("IntToByte",err)
   return buffer.Bytes()
}
func CheckErr(position string,err error) {
   if err != nil {
      fmt.Println("error ,pos:",position,err)
      os.Exit(1)
   }
}

package main
import "fmt"
func main() {
   bc := NewBlockChain()
   bc.AddBlock("A send B 1BTC")
   bc.AddBlock("B send C 1BTC")
   for _,block := range bc.blocks {
      fmt.Printf("Version : %d\n",block.Version)
      fmt.Printf("PerBlockHash : %x\n",block.PerBlockHash)
      fmt.Printf("Hash : %x\n",block.Hash)
      fmt.Printf("MerKelRoot : %x\n",block.MerKelRoot)
      fmt.Printf("TimeStamp : %d\n",block.TimeStamp)
      fmt.Printf("Bits : %d\n",block.Bits)
      fmt.Printf("Nonce : %d\n",block.Nonce)
      fmt.Printf("Data : %s\n",block.Data)
   }
}