Add fundrawtransaction RPC method

src/rpcclient.cpp

@@ -77,6 +77,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "signrawtransaction", 1 },
     { "signrawtransaction", 2 },
     { "sendrawtransaction", 1 },
+    { "fundrawtransaction", 1 },
     { "gettxout", 1 },
     { "gettxout", 2 },
     { "gettxoutproof", 0 },

src/rpcserver.cpp

@@ -332,6 +332,9 @@ static const CRPCCommand vRPCCommands[] =
     { "rawtransactions",    "getrawtransaction",      &getrawtransaction,      true  },
     { "rawtransactions",    "sendrawtransaction",     &sendrawtransaction,     false },
     { "rawtransactions",    "signrawtransaction",     &signrawtransaction,     false }, /* uses wallet if enabled */
+#ifdef ENABLE_WALLET
+    { "rawtransactions",    "fundrawtransaction",     &fundrawtransaction,     false },
+#endif
 
     /* Utility functions */
     { "util",               "createmultisig",         &createmultisig,         true  },

src/rpcserver.h

@@ -235,6 +235,7 @@ extern UniValue listlockunspent(const UniValue& params, bool fHelp);
 extern UniValue createrawtransaction(const UniValue& params, bool fHelp);
 extern UniValue decoderawtransaction(const UniValue& params, bool fHelp);
 extern UniValue decodescript(const UniValue& params, bool fHelp);
+extern UniValue fundrawtransaction(const UniValue& params, bool fHelp);
 extern UniValue signrawtransaction(const UniValue& params, bool fHelp);
 extern UniValue sendrawtransaction(const UniValue& params, bool fHelp);
 extern UniValue gettxoutproof(const UniValue& params, bool fHelp);

src/test/rpc_wallet_tests.cpp

@@ -248,6 +248,12 @@ BOOST_AUTO_TEST_CASE(rpc_wallet)
     }
     BOOST_CHECK(!notFound);
 
+    /*********************************
+     * 	     fundrawtransaction
+     *********************************/
+    BOOST_CHECK_THROW(CallRPC("fundrawtransaction 28z"), runtime_error);
+    BOOST_CHECK_THROW(CallRPC("fundrawtransaction 01000000000180969800000000001976a91450ce0a4b0ee0ddeb633da85199728b940ac3fe9488ac00000000"), runtime_error);
+
     /*
      * getblocksubsidy
      */

src/wallet/rpcwallet.cpp

@@ -2421,6 +2421,60 @@ UniValue listunspent(const UniValue& params, bool fHelp)
     return results;
 }
 
+UniValue fundrawtransaction(const UniValue& params, bool fHelp)
+{
+    if (!EnsureWalletIsAvailable(fHelp))
+        return NullUniValue;
+
+    if (fHelp || params.size() != 1)
+        throw runtime_error(
+                            "fundrawtransaction \"hexstring\"\n"
+                            "\nAdd inputs to a transaction until it has enough in value to meet its out value.\n"
+                            "This will not modify existing inputs, and will add one change output to the outputs.\n"
+                            "Note that inputs which were signed may need to be resigned after completion since in/outputs have been added.\n"
+                            "The inputs added will not be signed, use signrawtransaction for that.\n"
+                            "\nArguments:\n"
+                            "1. \"hexstring\"    (string, required) The hex string of the raw transaction\n"
+                            "\nResult:\n"
+                            "{\n"
+                            "  \"hex\":       \"value\", (string)  The resulting raw transaction (hex-encoded string)\n"
+                            "  \"fee\":       n,         (numeric) The fee added to the transaction\n"
+                            "  \"changepos\": n          (numeric) The position of the added change output, or -1\n"
+                            "}\n"
+                            "\"hex\"             \n"
+                            "\nExamples:\n"
+                            "\nCreate a transaction with no inputs\n"
+                            + HelpExampleCli("createrawtransaction", "\"[]\" \"{\\\"myaddress\\\":0.01}\"") +
+                            "\nAdd sufficient unsigned inputs to meet the output value\n"
+                            + HelpExampleCli("fundrawtransaction", "\"rawtransactionhex\"") +
+                            "\nSign the transaction\n"
+                            + HelpExampleCli("signrawtransaction", "\"fundedtransactionhex\"") +
+                            "\nSend the transaction\n"
+                            + HelpExampleCli("sendrawtransaction", "\"signedtransactionhex\"")
+                            );
+
+    RPCTypeCheck(params, boost::assign::list_of(UniValue::VSTR));
+
+    // parse hex string from parameter
+    CTransaction origTx;
+    if (!DecodeHexTx(origTx, params[0].get_str()))
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
+
+    CMutableTransaction tx(origTx);
+    CAmount nFee;
+    string strFailReason;
+    int nChangePos = -1;
+    if(!pwalletMain->FundTransaction(tx, nFee, nChangePos, strFailReason))
+        throw JSONRPCError(RPC_INTERNAL_ERROR, strFailReason);
+
+    UniValue result(UniValue::VOBJ);
+    result.push_back(Pair("hex", EncodeHexTx(tx)));
+    result.push_back(Pair("changepos", nChangePos));
+    result.push_back(Pair("fee", ValueFromAmount(nFee)));
+
+    return result;
+}
+
 UniValue zc_sample_joinsplit(const UniValue& params, bool fHelp)
 {
     if (fHelp) {