实践部分

创建Block

package core

import (
    "crypto/sha256"
    "encoding/hex"
    "time"
)

type Block struct {
    // 区块头
    Index         int64  // 区块编号
    Timestamp     int64  // 区块时间戳
    PrevBlockHash string // 上一个区块hash值
    Hash          string // 当前区块hash值

    // 区块体
    Data string // 区块数据
}

// 创建hash值
func caculateHash(b Block) string {
    blockData := string(b.Index) + string(b.Timestamp) + b.PrevBlockHash
    hashInBytes := sha256.Sum256([]byte(blockData))
    return hex.EncodeToString(hashInBytes[:])
}

// 创建新的区块
func GenerateNewBlock(preBlock Block, data string) Block {
    newBlock := Block{}
    newBlock.Index = preBlock.Index + 1
    newBlock.PrevBlockHash = preBlock.Hash
    newBlock.Timestamp = time.Now().Unix()
    newBlock.Data = data
    newBlock.Hash = caculateHash(newBlock)
    return newBlock
}

// 创世区块
func GenerateGenesisBlock() Block {
    preBlock := Block{}
    preBlock.Index = -1
    preBlock.Hash = ""
    return GenerateNewBlock(preBlock, "Genesis Block")
}

创建Blockchain

package core

import (
    "fmt"
    "log"
)

type Blockchain struct {
    Blocks []*Block
}

func NewBlockChain() *Blockchain {
    genesisBlock := GenerateGenesisBlock()
    blockchain := Blockchain{}
    blockchain.ApendBlock(&genesisBlock)
    return &blockchain
}

func (bc *Blockchain) SendData(data string) {
    preBlock := bc.Blocks[len(bc.Blocks)-1]
    newBlock := GenerateNewBlock(*preBlock, data)
    bc.ApendBlock(&newBlock)
}

func (bc *Blockchain) ApendBlock(newBlock *Block) {
    if len(bc.Blocks) == 0 {
        bc.Blocks = append(bc.Blocks, newBlock)
        return
    }
    if isValid(*newBlock, *bc.Blocks[len(bc.Blocks)-1]) {
        bc.Blocks = append(bc.Blocks, newBlock)
    } else {
        log.Fatal("invalid block")
    }
}

func (bc *Blockchain) Print() {
    for _, Block := range bc.Blocks {
        fmt.Printf("Index: %d\n", Block.Index)
        fmt.Printf("PrevHash: %s\n", Block.PrevBlockHash)
        fmt.Printf("CurrHash: %s\n", Block.Hash)
        fmt.Printf("Data: %s\n", Block.Data)
        fmt.Printf("Timestamp: %d\n", Block.Timestamp)
        fmt.Println()
    }
}

func isValid(newBlock Block, oldBlock Block) bool {
    if newBlock.Index-1 != oldBlock.Index {
        return false
    }
    if newBlock.PrevBlockHash != oldBlock.Hash {
        return false
    }
    if caculateHash(newBlock) != newBlock.Hash {
        return false
    }
    return true
}

创建main文件

package main

import "demochain/core"

func main() {
    bc := core.NewBlockChain()
    bc.SendData("Send 1 BTC to Jartin")
    bc.SendData("Send 1 EOS to Jartin")
    bc.Print()
}


// 输出
MacintoshdeMacBook-Pro-139:cmd elasticnotes$ go run main.go 
Index: 0
PrevHash: 
CurrHash: 0d8845eb2da42f75aef4ee920f644975d73347e0331d17b37209c4f32ef4867f
Data: Genesis Block
Timestamp: 1677140165

Index: 1
PrevHash: 0d8845eb2da42f75aef4ee920f644975d73347e0331d17b37209c4f32ef4867f
CurrHash: b11305449703848e79f02f0ba7f7db6bdd085a4a5ea50382ea4cca77644c376b
Data: Send 1 BTC to Jartin
Timestamp: 1677140165

Index: 2
PrevHash: b11305449703848e79f02f0ba7f7db6bdd085a4a5ea50382ea4cca77644c376b
CurrHash: 751c3793ee3492f5e050c6b662f4d832bc125dde0aae813147e5459abc23f29a
Data: Send 1 EOS to Jartin
Timestamp: 1677140165

创建Http Server

package main

import (
    "demochain/core"
    "encoding/json"
    "io"
    "net/http"
)

var blockchain *core.Blockchain

func run() {
    http.HandleFunc("/blockchain/get", blockchainGetHandler)
    http.HandleFunc("/blockchain/write", blockchainWriteHandler)
    http.ListenAndServe("localhost:8888", nil)
}

func blockchainGetHandler(w http.ResponseWriter, r *http.Request) {
    bytes, err := json.Marshal(blockchain)
    if err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }
    io.WriteString(w, string(bytes))
}

func blockchainWriteHandler(w http.ResponseWriter, r *http.Request) {
    blockData := r.URL.Query().Get("data")
    blockchain.SendData(blockData)
    blockchainGetHandler(w, r)
}

func main() {
    blockchain = core.NewBlockChain()
    run()
}

完整代码示例

• 目录层级

  MacintoshdeMacBook-Pro-139:demochain elasticnotes$ tree -L 3
  .
  ├── cmd
  │   └── main.go
  ├── core
  │   ├── Block.go
  │   └── Blockchain.go
  ├── go.mod
  └── rpc
      └── Server.go
  
  3 directories, 5 files
  

• 代码

  cmd/main.gocore/Block.gocore/Blockchain.gorpc/Server.go

  package main
  
  import "demochain/core"
  
  func main() {
      bc := core.NewBlockChain()
      bc.SendData("Send 1 BTC to Jartin")
      bc.SendData("Send 1 EOS to Jartin")
      bc.Print()
  }
  

  package core
  
  import (
      "crypto/sha256"
      "encoding/hex"
      "time"
  )
  
  type Block struct {
      // 区块头
      Index         int64  // 区块编号
      Timestamp     int64  // 区块时间戳
      PrevBlockHash string // 上一个区块hash值
      Hash          string // 当前区块hash值
  
      // 区块体
      Data string // 区块数据
  }
  
  // 创建hash值
  func caculateHash(b Block) string {
      blockData := string(b.Index) + string(b.Timestamp) + b.PrevBlockHash
      hashInBytes := sha256.Sum256([]byte(blockData))
      return hex.EncodeToString(hashInBytes[:])
  }
  
  // 创建新的区块
  func GenerateNewBlock(preBlock Block, data string) Block {
      newBlock := Block{}
      newBlock.Index = preBlock.Index + 1
      newBlock.PrevBlockHash = preBlock.Hash
      newBlock.Timestamp = time.Now().Unix()
      newBlock.Data = data
      newBlock.Hash = caculateHash(newBlock)
      return newBlock
  }
  
  // 创世区块
  func GenerateGenesisBlock() Block {
      preBlock := Block{}
      preBlock.Index = -1
      preBlock.Hash = ""
      return GenerateNewBlock(preBlock, "Genesis Block")
  }
  

  package core
  
  import (
      "fmt"
      "log"
  )
  
  type Blockchain struct {
      Blocks []*Block
  }
  
  func NewBlockChain() *Blockchain {
      genesisBlock := GenerateGenesisBlock()
      blockchain := Blockchain{}
      blockchain.ApendBlock(&genesisBlock)
      return &blockchain
  }
  
  func (bc *Blockchain) SendData(data string) {
      preBlock := bc.Blocks[len(bc.Blocks)-1]
      newBlock := GenerateNewBlock(*preBlock, data)
      bc.ApendBlock(&newBlock)
  }
  
  func (bc *Blockchain) ApendBlock(newBlock *Block) {
      if len(bc.Blocks) == 0 {
          bc.Blocks = append(bc.Blocks, newBlock)
          return
      }
      if isValid(*newBlock, *bc.Blocks[len(bc.Blocks)-1]) {
          bc.Blocks = append(bc.Blocks, newBlock)
      } else {
          log.Fatal("invalid block")
      }
  }
  
  func (bc *Blockchain) Print() {
      for _, Block := range bc.Blocks {
          fmt.Printf("Index: %d\n", Block.Index)
          fmt.Printf("PrevHash: %s\n", Block.PrevBlockHash)
          fmt.Printf("CurrHash: %s\n", Block.Hash)
          fmt.Printf("Data: %s\n", Block.Data)
          fmt.Printf("Timestamp: %d\n", Block.Timestamp)
          fmt.Println()
      }
  }
  
  func isValid(newBlock Block, oldBlock Block) bool {
      if newBlock.Index-1 != oldBlock.Index {
          return false
      }
      if newBlock.PrevBlockHash != oldBlock.Hash {
          return false
      }
      if caculateHash(newBlock) != newBlock.Hash {
          return false
      }
      return true
  }
  

  package main
  
  import (
      "demochain/core"
      "encoding/json"
      "io"
      "net/http"
  )
  
  var blockchain *core.Blockchain
  
  func run() {
      http.HandleFunc("/blockchain/get", blockchainGetHandler)
      http.HandleFunc("/blockchain/write", blockchainWriteHandler)
      http.ListenAndServe("localhost:8888", nil)
  }
  
  func blockchainGetHandler(w http.ResponseWriter, r *http.Request) {
      bytes, err := json.Marshal(blockchain)
      if err != nil {
          http.Error(w, err.Error(), http.StatusInternalServerError)
          return
      }
      io.WriteString(w, string(bytes))
  }
  
  func blockchainWriteHandler(w http.ResponseWriter, r *http.Request) {
      blockData := r.URL.Query().Get("data")
      blockchain.SendData(blockData)
      blockchainGetHandler(w, r)
  }
  
  func main() {
      blockchain = core.NewBlockChain()
      run()
  }
  

• 启动 访问结果

  MacintoshdeMacBook-Pro-139:rpc elasticnotes$ go run Server.go 
  

  http://localhost:8888/blockchain/get
  {
      "Blocks": [
          {
              "Index": 0,
              "Timestamp": 1677141979,
              "PrevBlockHash": "",
              "Hash": "0d8845eb2da42f75aef4ee920f644975d73347e0331d17b37209c4f32ef4867f",
              "Data": "Genesis Block"
          }
      ]
  }
  

  http://localhost:8888/blockchain/write?data=Send%202%20BTC%20to%20Jartin
  {
      "Blocks": [
          {
              "Index": 0,
              "Timestamp": 1677141979,
              "PrevBlockHash": "",
              "Hash": "0d8845eb2da42f75aef4ee920f644975d73347e0331d17b37209c4f32ef4867f",
              "Data": "Genesis Block"
          },
          {
              "Index": 1,
              "Timestamp": 1677142099,
              "PrevBlockHash": "0d8845eb2da42f75aef4ee920f644975d73347e0331d17b37209c4f32ef4867f",
              "Hash": "b11305449703848e79f02f0ba7f7db6bdd085a4a5ea50382ea4cca77644c376b",
              "Data": "Send 1 BTC to Jartin"
          },
          {
              "Index": 2,
              "Timestamp": 1677142109,
              "PrevBlockHash": "b11305449703848e79f02f0ba7f7db6bdd085a4a5ea50382ea4cca77644c376b",
              "Hash": "751c3793ee3492f5e050c6b662f4d832bc125dde0aae813147e5459abc23f29a",
              "Data": "Send 2 BTC to Jartin"
          }
      ]
  }