refactor: ♻️ mev: requestSignature

Signed-off-by: thanhpp <[email protected]>

pkg/mev/send_bundle.go

@@ -42,9 +42,14 @@ func SendBundle( // nolint: cyclop
 		return SendBundleResponse{}, fmt.Errorf("new http request error: %w", err)
 	}
 	if opts.flashbotSignKey != nil {
-		if err := signFlashbotRequest(opts.flashbotSignKey, httpReq, reqBody); err != nil {
+		signature, err := requestSignature(opts.flashbotSignKey, reqBody)
+		if err != nil {
 			return SendBundleResponse{}, fmt.Errorf("sign flashbot request error: %w", err)
 		}
+		httpReq.Header.Add(
+			"X-Flashbots-Signature",
+			fmt.Sprintf("%s:%s",
+				crypto.PubkeyToAddress(opts.flashbotSignKey.PublicKey), hexutil.Encode(signature)))
 	}
 	httpReq.Header.Add("Content-Type", "application/json")
 	httpReq.Header.Add("Accept", "application/json")
@@ -73,18 +78,14 @@ func SendBundle( // nolint: cyclop
 	return resp, nil
 }
 
-func signFlashbotRequest(key *ecdsa.PrivateKey, request *http.Request, body []byte) error {
+func requestSignature(key *ecdsa.PrivateKey, body []byte) ([]byte, error) {
 	hashed := crypto.Keccak256Hash(body).Hex()
 	signature, err := crypto.Sign(accounts.TextHash([]byte(hashed)), key)
 	if err != nil {
-		return fmt.Errorf("sign crypto error: %w", err)
+		return nil, fmt.Errorf("sign crypto error: %w", err)
 	}
 
-	request.Header.Add(
-		"X-Flashbots-Signature",
-		fmt.Sprintf("%s:%s", crypto.PubkeyToAddress(key.PublicKey), hexutil.Encode(signature)))
-
-	return nil
+	return signature, nil
 }
 
 type sendBundleOpts struct {