Cleaned up the generation of RLP encoded blocks

Author: maxrobot

src/block.json

@@ -1,21 +1,21 @@
 {
   "parentHash": "0xad34f0f919e4b06b18b0c674b8b9f6738a4878c76e837c8f31a2079f21dced1c",
-  "difficulty": 2,
+  "difficulty": "2",
   "extraData": "0xd78301080a846765746887676f312e392e33856c696e75780000000000000000e0ac79c5577889dfb5745ace9c5dfebe1a11bb19ced9b98b427e7bd4c85765ce17154e658440915743ec442fb64756483bc592616754d13a3c62fce5a56ac9f501",
-  "gasLimit": 16614106,
-  "gasUsed": 0,
+  "gasLimit": "16614106",
+  "gasUsed": "0",
   "hash": "0xd1d7abeb1345861e0103a24a239c178ccf930b069e50f2697d82fdd3496746ab",
   "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
   "miner": "0x0000000000000000000000000000000000000000",
   "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
   "nonce": "0x0000000000000000",
-  "number": 10,
+  "number": "10",
   "receiptsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
   "sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
-  "size": 606,
+  "size": "606",
   "stateRoot": "0xdb37435caa1fca7e1aa5b4da1c69fdf1d127232519eb3b1b5069825e6c62f5dc",
-  "timestamp": 1529396972,
-  "totalDifficulty": 21,
+  "timestamp": "1529396972",
+  "totalDifficulty": "21",
   "transactions": [],
   "transactionsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
   "uncles": []

src/cli/cli.go

@@ -80,10 +80,10 @@ func Launch(setup config.Setup) {
 		},
 	})
 
-	// Get block N
+	// Get block N and spew out the RLP encoded block
 	shell.AddCmd(&ishell.Cmd{
 		Name: "rlpEncodeBlock",
-		Help: "Gets specific block of Ethereum instance specified as from",
+		Help: "Request RLP encoded block [N] of chain [from]",
 		Func: func(c *ishell.Context) {
 			c.Println("===============================================================")
 			if len(c.Args) == 0 {
@@ -99,6 +99,25 @@ func Launch(setup config.Setup) {
 		},
 	})
 
+	// Get block N and spew out the RLP encoded block
+	shell.AddCmd(&ishell.Cmd{
+		Name: "getValidBlock",
+		Help: "Request block [N] from chain [from], calculates the prefixes required for submission to chain [to]",
+		Func: func(c *ishell.Context) {
+			c.Println("===============================================================")
+			if len(c.Args) == 0 {
+				c.Println("Choose a block.")
+			} else if len(c.Args) > 1 {
+				c.Println("Too many arguments entered.")
+			} else {
+				block := strToHex(c.Args[0])
+				c.Println("RLP encode block: " + c.Args[0])
+				calculateRlpEncoding(client, block)
+			}
+			c.Println("===============================================================")
+		},
+	})
+
 	// run shell
 	shell.Run()
 }

src/cli/rpc.go

@@ -3,14 +3,13 @@
 package cli
 
 import (
-	"fmt"
-	// "math/big"
 	"encoding/hex"
+	"fmt"
+	"reflect"
 	"strconv"
 
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/rpc"
-	// "github.com/ethereum/go-ethereum/common"
 )
 
 type Header struct {
@@ -21,7 +20,7 @@ type Header struct {
 	TxHash      string `json:"transactionsRoot" gencodec:"required"`
 	ReceiptHash string `json:"receiptsRoot"     gencodec:"required"`
 	Bloom       string `json:"logsBloom"        gencodec:"required"`
-	Difficulty  string `json:"difficulty"		   gencodec:"required"`
+	Difficulty  string `json:"difficulty"		  	gencodec:"required"`
 	Number      string `json:"number"           gencodec:"required"`
 	GasLimit    string `json:"gasLimit"         gencodec:"required"`
 	GasUsed     string `json:"gasUsed"          gencodec:"required"`
@@ -62,49 +61,42 @@ func rlpEncodeBlock(client *rpc.Client, block string) {
 		fmt.Println("can't get requested block:", err)
 		return
 	} else {
+		blockInterface := generateInterface(blockHeader)
+		encodedBlock := EncodeBlock(blockInterface)
+		fmt.Printf("%+x\n", encodedBlock)
+	}
+}
 
-		encodedBlock := EncodeBlock(blockHeader)
-		fmt.Printf("%+v\n", encodedBlock)
+func calculateRlpEncoding(client *rpc.Client, block string) {
+	var blockHeader Header
+	err := client.Call(&blockHeader, "eth_getBlockByNumber", block, true)
+	if err != nil {
+		fmt.Println("can't get requested block:", err)
+		return
+	} else {
+		blockInterface := generateInterface(blockHeader)
+		encodedBlock := EncodeBlock(blockInterface)
+		fmt.Printf("%+x\n", encodedBlock)
 	}
 }
 
-func EncodeBlock(header Header) (h []byte) {
-	// Annoyingly we need to funk around with the fields ugly for the time being
-	encParentHash, _ := hex.DecodeString(header.ParentHash[2:])
-	encUncleHash, _ := hex.DecodeString(header.UncleHash[2:])
-	encCoinbase, _ := hex.DecodeString(header.Coinbase[2:])
-	encRoot, _ := hex.DecodeString(header.Root[2:])
-	encTxHash, _ := hex.DecodeString(header.TxHash[2:])
-	encReceiptHash, _ := hex.DecodeString(header.ReceiptHash[2:])
-	encBloom, _ := hex.DecodeString(header.Bloom[2:])
-	encDifficulty, _ := hex.DecodeString(header.Difficulty[2:])
-	encNumber, _ := hex.DecodeString(header.Number[2:])
-	encGasLimit, _ := hex.DecodeString(header.GasLimit[2:])
-	encGasUsed, _ := hex.DecodeString(header.GasUsed[2:])
-	encTime, _ := hex.DecodeString(header.Time[2:])
-	encExtra, _ := hex.DecodeString(header.Extra[2:])
-	encMixDigest, _ := hex.DecodeString(header.MixDigest[2:])
-	encNonce, _ := hex.DecodeString(header.Nonce[2:])
+func generateInterface(blockHeader Header) (rest interface{}) {
+	blockInterface := []interface{}{}
+	s := reflect.ValueOf(&blockHeader).Elem()
 
-	x := []interface{}{
-		encParentHash,
-		encUncleHash,
-		encCoinbase,
-		encRoot,
-		encTxHash,
-		encReceiptHash,
-		encBloom,
-		encDifficulty,
-		encNumber,
-		encGasLimit,
-		encGasUsed,
-		encTime,
-		encExtra,
-		encMixDigest,
-		encNonce,
+	// Append items into the interface
+	for i := 0; i < s.NumField(); i++ {
+		f := s.Field(i).String()
+		element, _ := hex.DecodeString(f[2:])
+		blockInterface = append(blockInterface, element)
 	}
 
-	h, _ = rlp.EncodeToBytes(x)
+	return blockInterface
+}
+
+func EncodeBlock(blockInterface interface{}) (h []byte) {
+	// Encode the block
+	h, _ = rlp.EncodeToBytes(blockInterface)
 
 	return h
 }

src/main.go

@@ -3,9 +3,9 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"os"
-	"flag"
 
 	"github.com/validation/src/cli"
 	"github.com/validation/src/config"