list blocks

core/Block.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"encoding/gob"
+	"encoding/hex"
 	"time"
 )
 
@@ -12,10 +13,19 @@ type Block struct {
 	Timestamp    time.Time
 	Hash         []byte
 	PreviousHash []byte
-	Data         []byte
+	Data         interface{}
 }
 
-func newBlock(previousHash []byte, data []byte) Block {
+// BlockJSON is a modified Block struct for json representation
+type BlockJSON struct {
+	Timestamp     time.Time
+	Hash          string
+	PreviouseHash string
+	Data          interface{}
+}
+
+// NewBlock creates a new Block
+func NewBlock(previousHash []byte, data interface{}) Block {
 	block := Block{Timestamp: time.Now(), PreviousHash: previousHash, Data: data}
 
 	block.calculateHash()
@@ -37,3 +47,8 @@ func (block *Block) calculateHash() {
 
 	block.Hash = sum
 }
+
+// EncodeJSON encodes a Block to a JSON representable struct
+func (block *Block) EncodeJSON() BlockJSON {
+	return BlockJSON{Timestamp: block.Timestamp, PreviouseHash: hex.EncodeToString(block.PreviousHash), Hash: hex.EncodeToString(block.Hash), Data: block.Data}
+}

core/Blockchain.go

@@ -9,7 +9,8 @@ func (bc *Blockchain) addBlock(block Block) {
 	bc.blocks = append(bc.blocks, block)
 }
 
-func newBlockchain() Blockchain {
+// NewBlockchain creates a new Blockchain
+func NewBlockchain() Blockchain {
 
 	blockchain := Blockchain{blocks: make([]Block, 0)}
 
@@ -20,6 +21,6 @@ func newBlockchain() Blockchain {
 }
 
 func generateGenesisBlock() Block {
-	block := newBlock([]byte{}, []byte("Genesis"))
+	block := NewBlock([]byte{}, []byte("Genesis"))
 	return block
 }

core/Server.go

@@ -1,9 +1,9 @@
 package main
 
 import (
+	"encoding/gob"
 	"encoding/json"
 	"net/http"
-	"strings"
 )
 
 var blockchain Blockchain
@@ -11,17 +11,15 @@ var blockchain Blockchain
 // StartServer starts the HTTP server on port 8080
 func StartServer() {
 
-	blockchain = newBlockchain()
+	gob.Register(Block{})
+	gob.Register(Transaction{})
+	gob.Register(Blockchain{})
 
-	data, _ := json.Marshal(Transaction{Sender: "foo", Receiver: "bar", Amount: 100})
-	block := newBlock(blockchain.blocks[0].Hash, data)
+	blockchain = NewBlockchain()
+	transaction := Transaction{Sender: "foo", Receiver: "bar", Amount: 100}
+	block := NewBlock(blockchain.blocks[0].Hash, transaction)
 	blockchain.addBlock(block)
 
-	data2, _ := json.Marshal(Transaction{Sender: "bar", Receiver: "baz", Amount: 5000})
-	block = newBlock(blockchain.blocks[1].Hash, data2)
-	blockchain.addBlock(block)
-
-	http.HandleFunc("/", sayHello)
 	http.HandleFunc("/blockchain", listBlocks)
 
 	if err := http.ListenAndServe(":8080", nil); err != nil {
@@ -29,13 +27,13 @@ func StartServer() {
 	}
 }
 
-func sayHello(w http.ResponseWriter, r *http.Request) {
-	message := r.URL.Path
-	message = strings.TrimPrefix(message, "/")
-	message = "Hello " + message
-	w.Write([]byte(message))
-}
-
 func listBlocks(w http.ResponseWriter, r *http.Request) {
-	json.NewEncoder(w).Encode(blockchain.blocks)
+
+	var jsonBlocks []BlockJSON
+
+	for _, block := range blockchain.blocks {
+		jsonBlocks = append(jsonBlocks, block.EncodeJSON())
+	}
+
+	json.NewEncoder(w).Encode(jsonBlocks)
 }

core/Transaction.go

@@ -0,0 +1,8 @@
+package main
+
+// Transaction struct
+type Transaction struct {
+	Sender   string
+	Receiver string
+	Amount   int
+}

core/main.go

@@ -1,40 +1,5 @@
 package main
 
-import (
-	"encoding/hex"
-	"encoding/json"
-	"fmt"
-)
-
-// Transaction struct
-type Transaction struct {
-	Sender   string
-	Receiver string
-	Amount   int
-}
-
 func main() {
-	blockchain := newBlockchain()
-
 	StartServer()
-
-	data, _ := json.Marshal(Transaction{Sender: "foo", Receiver: "bar", Amount: 100})
-	block := newBlock(blockchain.blocks[0].Hash, data)
-	blockchain.addBlock(block)
-
-	data2, _ := json.Marshal(Transaction{Sender: "bar", Receiver: "baz", Amount: 5000})
-	block = newBlock(blockchain.blocks[1].Hash, data2)
-	blockchain.addBlock(block)
-
-	for i := 0; i < len(blockchain.blocks); i++ {
-
-		block := blockchain.blocks[i]
-		fmt.Println("Block " + string(i))
-		fmt.Println(hex.EncodeToString(block.PreviousHash))
-		fmt.Println(hex.EncodeToString(block.Hash))
-
-		data := string(block.Data)
-		fmt.Println("Data: " + data)
-	}
-
 }