From c55e1b495cb1082b5bb11b3c2e6e3d0943dae3cd Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Thu, 8 Aug 2019 10:22:10 +0200
Subject: [PATCH] ethapi: implement filltransaction

---
 internal/ethapi/api.go      | 16 ++++++++++++++++
 internal/web3ext/web3ext.go |  6 ++++++
 2 files changed, 22 insertions(+)

diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index a00598f820..d27c9ec9bf 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -1441,6 +1441,22 @@ func (s *PublicTransactionPoolAPI) SendTransaction(ctx context.Context, args Sen
 	return SubmitTransaction(ctx, s.b, signed)
 }
 
+// FillTransaction fills the defaults (nonce, gas, gasPrice) on a given unsigned transaction,
+// and returns it to the caller for further processing (signing + broadcast)
+func (s *PublicTransactionPoolAPI) FillTransaction(ctx context.Context, args SendTxArgs) (*SignTransactionResult, error) {
+	// Set some sanity defaults and terminate on failure
+	if err := args.setDefaults(ctx, s.b); err != nil {
+		return nil, err
+	}
+	// Assemble the transaction and obtain rlp
+	tx := args.toTransaction()
+	data, err := rlp.EncodeToBytes(tx)
+	if err != nil {
+		return nil, err
+	}
+	return &SignTransactionResult{data, tx}, nil
+}
+
 // SendRawTransaction will add the signed transaction to the transaction pool.
 // The sender is responsible for signing the transaction and using the correct nonce.
 func (s *PublicTransactionPoolAPI) SendRawTransaction(ctx context.Context, encodedTx hexutil.Bytes) (common.Hash, error) {
diff --git a/internal/web3ext/web3ext.go b/internal/web3ext/web3ext.go
index 4a5d4b4ddb..86e5754392 100644
--- a/internal/web3ext/web3ext.go
+++ b/internal/web3ext/web3ext.go
@@ -483,6 +483,12 @@ web3._extend({
 			params: 1,
 			inputFormatter: [web3._extend.formatters.inputTransactionFormatter]
 		}),
+		new web3._extend.Method({
+			name: 'fillTransaction',
+			call: 'eth_fillTransaction',
+			params: 1,
+			inputFormatter: [web3._extend.formatters.inputTransactionFormatter]
+		}),
 		new web3._extend.Method({
 			name: 'getHeaderByNumber',
 			call: 'eth_getHeaderByNumber',