Refactor Blockchain Interface

core/Block.go

@@ -17,14 +17,20 @@ type Block struct {
 }
 
 // NewBlock creates a new Block
-func NewBlock(previousHash string, data []Transaction) Block {
-	block := Block{Timestamp: time.Now(), PreviousHash: previousHash, Data: data}
+func NewBlock(previousHash string) Block {
+	block := Block{Timestamp: time.Now(), PreviousHash: previousHash}
 
 	block.calculateHash()
 
 	return block
 }
 
+// AddTransaction takes in a transaction and adds it to the block
+func (block *Block) AddTransaction(transaction Transaction) error {
+	block.Data = append(block.Data, transaction)
+	return nil
+}
+
 func (block *Block) calculateHash() {
 	var buffer bytes.Buffer
 	encoder := gob.NewEncoder(&buffer)

core/Blockchain.go

@@ -5,7 +5,8 @@ type Blockchain struct {
 	blocks []Block
 }
 
-func (bc *Blockchain) addBlock(block Block) {
+// AddBlock adds a block to the chain
+func (bc *Blockchain) AddBlock(block Block) {
 	bc.blocks = append(bc.blocks, block)
 }
 
@@ -15,14 +16,20 @@ func NewBlockchain() Blockchain {
 	blockchain := Blockchain{blocks: make([]Block, 0)}
 
 	genesisBlock := generateGenesisBlock()
-	blockchain.addBlock(genesisBlock)
+	blockchain.AddBlock(genesisBlock)
 
 	return blockchain
 }
 
 func generateGenesisBlock() Block {
 
+	block := NewBlock("0")
 	transaction := Transaction{Amount: 0, Sender: "0", Receiver: "0", Message: "Genesis"}
-	block := NewBlock("0", []Transaction{transaction})
+	block.AddTransaction(transaction)
 	return block
 }
+
+// GetLastBlock returns the latest block on the chain
+func (bc *Blockchain) GetLastBlock() Block {
+	return bc.blocks[len(bc.blocks)-1]
+}

core/Server.go

@@ -16,9 +16,12 @@ func StartServer() {
 	gob.Register(Blockchain{})
 
 	blockchain = NewBlockchain()
+	block := NewBlock(blockchain.GetLastBlock().Hash)
+
 	transaction := Transaction{Sender: "foo", Receiver: "bar", Amount: 100}
-	block := NewBlock(blockchain.blocks[0].Hash, []Transaction{transaction})
-	blockchain.addBlock(block)
+	block.AddTransaction(transaction)
+
+	blockchain.AddBlock(block)
 
 	http.HandleFunc("/blockchain", listBlocks)