GO语言构建区块链

学习爱慕课：https://www.imooc.com/learn/1011
创建第一个区块链项目

读取区块

插入一个区块数据

1.rpc/Server.go

package main

import (
	"encoding/json"
	"hello/core"
	"io"
	"net/http"
)
var blockchain *core.Blockchain
func run()  {
	http.HandleFunc("/blockchain/get",blockchainGetHandLer)
	http.HandleFunc("/blockchain/write",blockchainWiiteHandLer)
	http.ListenAndServe("localhost:9998",nil)
}

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

func blockchainWiiteHandLer(w http.ResponseWriter,r *http.Request)  {
	blockData := r.URL.Query().Get("data")
	blockchain.SendData(blockData)
	blockchainGetHandLer(w,r)
}
func main()  {
	blockchain = core.NewBlockchain()
	run()
}

2.core/Blockchain.go

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 blick")
	}

}
func (bc *Blockchain) Print()  {
	for _, block :=  range bc.Blocks{
		fmt.Printf("index: %d\n",block.Index)
		fmt.Printf("prev.hash: %s\n",block.PrevBlockHash)
		fmt.Printf("curr.hash: %s\n",block.Hash)
		fmt.Printf("data: %s\n",block.Date)
		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 calculateHash(newBlock) != newBlock.Hash {
		return false
	}
	return true
}

3.core/Block.go

package core

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

//区块结构图
type Block struct {
    Index int64             //区块编号
    Timestamp int64         //区块时间错
    PrevBlockHash string    //当前区块哈希值
    Hash string             //当前区块hash
    Date string             //区块数据
}
func calculateHash(b Block) string {
    blockData := string(b.Index)+string(b.Timestamp)+b.PrevBlockHash+b.Date
    hashInBytes := sha256.Sum256([]byte(blockData))
    return hex.EncodeToString(hashInBytes[:])
}
func GenerateNewBlock(preBlock Block,data string) Block  {
    newBlock := Block{}
    newBlock.Index = preBlock.Index + 1
    newBlock.PrevBlockHash = preBlock.Hash
    newBlock.Timestamp = time.Now().Unix()
    newBlock.Date = data
    newBlock.Hash = calculateHash(newBlock)
    return newBlock
}
func GenerateGenesisBlock() Block  {
    preBlock := Block{}
    preBlock.Index = -1
    preBlock.Hash = ""
    return  GenerateNewBlock(preBlock,"Genesis Block")
}

4.cmd/main.go

package main

import (
	"hello/core"
)

func main() {

	bc := core.NewBlockchain()
	bc.SendData("send 1 BTC to Jacky")
	bc.SendData("send 1 EOS to Jack")
	bc.Print()

}