added GetBlockchain in REST API of the serverCA, also added the visualization to the serverCA webapp

serverCA/blockchain.go

@@ -0,0 +1,115 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"github.com/fatih/color"
+)
+
+type Block struct {
+	Hash         string    `json:"hash"`
+	Height       int64     `json:"height"`
+	Date         time.Time `json:"date"`
+	PreviousHash string    `json:"previoushash"`
+	NextHash     string    `json:"nexthash"`
+	Data         []Address `json:"data"`
+	Emitter      string    `json:"emitter"` //the ID of the peer that has emmited the block
+}
+
+type Blockchain struct {
+	GenesisBlock string    `json:"genesisblock"`
+	LastUpdate   time.Time `json:"lastupdate"`
+	Blocks       []Block   `json:"blocks"`
+}
+
+var blockchain Blockchain
+
+func (bc *Blockchain) getBlockByHash(hash string) (Block, error) {
+	for _, block := range bc.Blocks {
+		if block.Hash == hash {
+			return block, nil
+		}
+	}
+	var b Block
+	return b, errors.New("Block Hash not found")
+}
+
+func (bc *Blockchain) blockExists(block Block) bool {
+	for _, b := range bc.Blocks {
+		if b.Hash == block.Hash {
+			return true
+		}
+	}
+	return false
+}
+
+func (bc *Blockchain) addBlock(block Block) error {
+	if blockchain.blockExists(block) {
+		return errors.New("[Error adding Block]: Block already exists in the Blockchain")
+	}
+	if len(bc.Blocks) > 0 {
+		bc.Blocks[len(bc.Blocks)-1].NextHash = block.Hash
+	} else {
+		bc.GenesisBlock = block.Hash
+	}
+	bc.Blocks = append(bc.Blocks, block)
+
+	return nil
+}
+
+func reconstructBlockchainFromBlock(urlAPI string, h string) {
+	color.Yellow("reconstructing the blockchain from last block in memory")
+	var block Block
+	var err error
+
+	block, err = blockchain.getBlockByHash(h)
+	check(err)
+
+	if h == "" {
+		//no genesis block yet
+		color.Green(urlAPI + "/blocks/genesis")
+		res, err := http.Get(urlAPI + "/blocks/genesis")
+		check(err)
+		body, err := ioutil.ReadAll(res.Body)
+		check(err)
+		err = json.Unmarshal(body, &block)
+		check(err)
+		color.Yellow("[New Block]: " + block.Hash)
+		err = blockchain.addBlock(block)
+		check(err)
+	} else {
+		block.NextHash = h
+	}
+
+	for block.NextHash != "" && block.Hash != "" {
+		res, err := http.Get(urlAPI + "/blocks/next/" + block.Hash)
+		check(err)
+		body, err := ioutil.ReadAll(res.Body)
+		check(err)
+		err = json.Unmarshal(body, &block)
+		check(err)
+		if block.Hash != "" {
+			color.Yellow("[New Block]: " + block.Hash)
+			err = blockchain.addBlock(block)
+			check(err)
+		}
+	}
+	blockchain.print()
+}
+
+func (bc *Blockchain) print() {
+	color.Green("Printing Blockchain stored in memory")
+	color.Green("Genesis Block: " + bc.GenesisBlock)
+	for _, b := range bc.Blocks {
+		color.Green("Block height:")
+		fmt.Println(b.Height)
+		color.Green("Hash: " + b.Hash)
+		color.Green("Date: " + b.Date.String())
+		color.Green("---")
+	}
+}