Merge pull request #14 from tdadadavid/feat/blockchain_db

Feat: add chain utils

Author: tdadadavid

cmd/block_functions.go

@@ -13,15 +13,19 @@ func init() {
 	blockChain = chain.New(context.Background(), "/data/blocks")
 }
 
-func printChain() {
-	blockChain.PrettyPrint()
-}
-
 func addBlock(data string) {
 	blockChain.AddBlock(data)
 }
 
-func printLastBlockOnChain() {
+func printBlock(hash string) {
+	blockChain.PrintBlock(hash)
+} 
+
+func printChain(_ string) {
+	blockChain.PrintChain()
+}
+
+func printLastBlockOnChain(_ string) {
 	b, _ := blockChain.FindLast()
 	fmt.Printf("Block {%v}\n", b)
 }

cmd/print_blockchain.go

@@ -14,27 +14,33 @@ var printCmd = &cobra.Command{
 	Short:   "View the chain",
 	Long:    "🥽 into the chain",
 	Example: "block print <chain|block>",
-	Args:    cobra.ExactArgs(1),
+	Args:    cobra.MaximumNArgs(3),
 	Run: func(cmd *cobra.Command, args []string) {
 		input := strings.ToLower(args[0])
+		value := ""
+		if len(args) > 1 {
+			value = strings.ToLower(args[1])
+		}
 
 		if input == "" {
 			logger.Error("empty or wrong input passed", slog.String("got", input))
 			os.Exit(100)
 		}
 
-		if CommandToHandlers[input] == nil {
-			fmt.Println("Not implemented")
+		command, ok := CommandToHandlers[input]
+		if !ok {
+			fmt.Println("not implemented")
+			return
 		}
-
-		command := CommandToHandlers[input]
-		command()
+		command(value)
 	},
 }
 
 func init() {
 	rootCmd.AddCommand(printCmd)
 
+	CommandToHandlers["b"] = printBlock
 	CommandToHandlers["bc"] = printChain
 	CommandToHandlers["last"] = printLastBlockOnChain
+
 }

cmd/root.go

@@ -8,7 +8,8 @@ import (
 	"github.com/spf13/cobra"
 )
 
-var CommandToHandlers = map[string]func(){}
+
+var CommandToHandlers = map[string]func(string){}
 
 var (
 	logger *slog.Logger

pkg/block/block.go

@@ -66,6 +66,7 @@ func New(data string, prevBlkHash string, height int32) (block Block) {
 	return block
 }
 
+
 // NewGenesisBlock creates the first block on the chain known as the 'GENESIS_BLOCK'
 //
 // Note:
@@ -101,6 +102,13 @@ func (b *Block) GetPrevBlockHash() string {
 	return b.PrevBlockHash
 }
 
+// String returns a string representation of a Block
+// This implements the Stringer interface to enable us printing like this fmt.Println(&block)
+func (b *Block) String() string {
+	return fmt.Sprintf("{Hash: %q, PrevBlockHash: %q, Height: %d, Timestamp: %d, Transactions: %q, Nonce: %d}",
+		b.Hash, b.PrevBlockHash, b.Height, b.Timestamp, b.Transactions, b.Nonce)
+}
+
 // Serialize converts the Block in binary data stored in the storage
 //
 // Process:

pkg/chain/chain.go

@@ -2,7 +2,6 @@ package chain
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 
 	"github.com/dgraph-io/badger/v4"
@@ -98,15 +97,37 @@ func (c *Chain) AddBlock(data string) {
 	c.currentHash = newBlock.GetHash()
 }
 
-// PrettyPrint this formats the chain into a readable json format for easy debugging
-func (c *Chain) PrettyPrint() {
-	json, err := json.MarshalIndent(c, "Blockchain ", "")
-	if err != nil {
-		fmt.Printf("error marshalling block: %s", err)
+// GetAllBlocks retrieves all blocks from the chain store
+//
+// Process:
+// 	- It first creates an iterator object for the loop process
+//  - while there is a block on the chain it gets it and appends it to a slice of blocks
+//  - Reverse the blocks to get them in chronological order (oldest first)
+//
+// Returns:
+// 	- `blocks []*block.Block`: a slice of blocks for this chain
+//  - `err error`: an error object
+func (c *Chain) GetAllBlocks() (blocks []*block.Block, err error) {
+	iter := c.iter()
+
+	for iter.HasNext(c.chainCtx) {
+		block := iter.Next(c.chainCtx)
+		if block == nil {
+			err = fmt.Errorf("failed to get block %s", c.currentHash)
+			return blocks, err
+		}
+		blocks = append(blocks, block)
 	}
-	fmt.Println(string(json))
+
+	// Reverse the blocks to get them in chronological order (oldest first)
+	for i, j := 0, len(blocks)-1; i < j; i, j = i+1, j-1 {
+		blocks[i], blocks[j] = blocks[j], blocks[i]
+	}
+	
+	return blocks, err
 }
 
+
 // iter add a block to the chain
 //
 // Process:
@@ -121,7 +142,4 @@ func (c *Chain) iter() ChainIterator {
 	}
 }
 
-// Utility functions
-func (c *Chain) FindLast() (block.Block, error) {
-	return c.store.FindLast(c.chainCtx)
-}
+

pkg/chain/chain_utils.go

@@ -0,0 +1,49 @@
+package chain
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/tdadadavid/block/pkg/block"
+)
+
+
+func (c *Chain) FindLast() (block.Block, error) {
+	return c.store.FindLast(c.chainCtx)
+}
+
+func (c *Chain) PrintBlock(hash string) {
+	block, err := c.store.FindByHash(context.Background(), hash)
+	if err != nil {
+		fmt.Printf("err printing block")
+	}
+	fmt.Println(block)
+}
+
+// PrintChain prints the blockchain in a formatted way
+func (c *Chain) PrintChain() {
+	var builder strings.Builder
+	builder.WriteString("Blockchain {\n")
+	builder.WriteString(fmt.Sprintf("  currentHash: %q\n", c.currentHash))
+	
+	// Get blocks from the store
+	blocks, err := c.GetAllBlocks()
+	if err != nil {
+		fmt.Printf("Blockchain {\n  currentHash: %q\n  blocks: [Error fetching blocks: %v]\n}", 
+			c.currentHash, err)
+	}
+	
+	builder.WriteString("  blocks: [\n")
+	for i, block := range blocks {
+		builder.WriteString(fmt.Sprintf("    %s", block.String()))
+		if i < len(blocks)-1 {
+			builder.WriteString(",")
+		}
+		builder.WriteString("\n")
+	}
+	builder.WriteString("  ]\n")
+	builder.WriteString("}")
+	
+	fmt.Println(builder.String())
+}