From b540bf6a0e6c6079fbe7d2a6881519ab6a22b97a Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Thu, 25 Jan 2018 13:51:55 +0100
Subject: [PATCH] ethapi: add personal.signTransaction

---
 internal/ethapi/api.go      | 40 +++++++++++++++++++++++++++++++++++++
 internal/web3ext/web3ext.go |  6 ++++++
 2 files changed, 46 insertions(+)

diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 55bd5aa1ba..34de5d0770 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -370,6 +370,46 @@ func (s *PrivateAccountAPI) SendTransaction(ctx context.Context, args SendTxArgs
 	return submitTransaction(ctx, s.b, signed)
 }
 
+// SignTransaction will create a transaction from the given arguments and
+// tries to sign it with the key associated with args.To. If the given passwd isn't
+// able to decrypt the key it fails. The transaction is returned in RLP-form, not broadcast
+// to other nodes
+func (s *PrivateAccountAPI) SignTransaction(ctx context.Context, args SendTxArgs, passwd string) (*SignTransactionResult, error) {
+	// Look up the wallet containing the requested signer
+	account := accounts.Account{Address: args.From}
+
+	wallet, err := s.am.Find(account)
+	if err != nil {
+		return nil, err
+	}
+	if args.Nonce == nil {
+		// Hold the addresse's mutex around signing to prevent concurrent assignment of
+		// the same nonce to multiple accounts.
+		s.nonceLock.LockAddr(args.From)
+		defer s.nonceLock.UnlockAddr(args.From)
+	}
+	// Set some sanity defaults and terminate on failure
+	if err := args.setDefaults(ctx, s.b); err != nil {
+		return nil, err
+	}
+	// Assemble the transaction and sign with the wallet
+	tx := args.toTransaction()
+
+	var chainID *big.Int
+	if config := s.b.ChainConfig(); config.IsEIP155(s.b.CurrentBlock().Number()) {
+		chainID = config.ChainId
+	}
+	tx, err = wallet.SignTxWithPassphrase(account, passwd, tx, chainID)
+	if err != nil {
+		return nil, err
+	}
+	data, err := rlp.EncodeToBytes(tx)
+	if err != nil {
+		return nil, err
+	}
+	return &SignTransactionResult{data, tx}, nil
+}
+
 // signHash is a helper function that calculates a hash for the given message that can be
 // safely used to calculate a signature from.
 //
diff --git a/internal/web3ext/web3ext.go b/internal/web3ext/web3ext.go
index e11aa402f5..a6b81b4c2a 100644
--- a/internal/web3ext/web3ext.go
+++ b/internal/web3ext/web3ext.go
@@ -517,6 +517,12 @@ web3._extend({
 			call: 'personal_deriveAccount',
 			params: 3
 		}),
+		new web3._extend.Method({
+			name: 'signTransaction',
+			call: 'personal_signTransaction',
+			params: 2,
+			inputFormatter: [web3._extend.formatters.inputTransactionFormatter, null]
+		}),
 	],
 	properties: [
 		new web3._extend.Property({