Merge pull request #1536

693c1908 wallet: add a node RPC cache layer for simple RPC calls (moneromooo-monero)
d86ae2be wallet2: reuse fake outs when adjusting fee on transfer (moneromooo-monero)
64da0983 core: don't try to deserialize an empty extra to remove a field (moneromooo-monero)

8 files changed, 316 insertions, 102 deletions

diff --git a/src/cryptonote_core/cryptonote_format_utils.cpp b/src/cryptonote_core/cryptonote_format_utils.cpp
index b5f2b069d..e04409d87 100644
--- a/src/cryptonote_core/cryptonote_format_utils.cpp
+++ b/src/cryptonote_core/cryptonote_format_utils.cpp
@@ -371,6 +371,8 @@ namespace cryptonote
   //---------------------------------------------------------------
   bool remove_field_from_tx_extra(std::vector<uint8_t>& tx_extra, const std::type_info &type)
   {
+    if (tx_extra.empty())
+      return true;
     std::string extra_str(reinterpret_cast<const char*>(tx_extra.data()), tx_extra.size());
     std::istringstream iss(extra_str);
     binary_archive<false> ar(iss);
diff --git a/src/wallet/CMakeLists.txt b/src/wallet/CMakeLists.txt
index 53b0a794f..922464a3c 100644
--- a/src/wallet/CMakeLists.txt
+++ b/src/wallet/CMakeLists.txt
@@ -34,6 +34,7 @@ set(wallet_sources
   password_container.cpp
   wallet2.cpp
   wallet_args.cpp
+  node_rpc_proxy.cpp
   api/wallet.cpp
   api/wallet_manager.cpp
   api/transaction_info.cpp
@@ -55,6 +56,7 @@ set(wallet_private_headers
   wallet_rpc_server.h
   wallet_rpc_server_commands_defs.h
   wallet_rpc_server_error_codes.h
+  node_rpc_proxy.h
   api/wallet.h
   api/wallet_manager.h
   api/transaction_info.h
diff --git a/src/wallet/node_rpc_proxy.cpp b/src/wallet/node_rpc_proxy.cpp
new file mode 100644
index 000000000..d7f755e36
--- /dev/null
+++ b/src/wallet/node_rpc_proxy.cpp
@@ -0,0 +1,134 @@
+// Copyright (c) 2017, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "node_rpc_proxy.h"
+#include "rpc/core_rpc_server_commands_defs.h"
+#include "common/json_util.h"
+#include "storages/http_abstract_invoke.h"
+
+using namespace epee;
+
+namespace tools
+{
+
+void NodeRPCProxy::init(const std::string &daemon_address)
+{
+  m_daemon_address = daemon_address;
+
+  m_height = 0;
+  m_height_time = 0;
+  for (auto &slot: m_earliest_height)
+    slot = 0;
+  m_dynamic_per_kb_fee_estimate = 0;
+  m_dynamic_per_kb_fee_estimate_cached_height = 0;
+  m_dynamic_per_kb_fee_estimate_grace_blocks = 0;
+}
+
+boost::optional<std::string> NodeRPCProxy::get_height(uint64_t &height)
+{
+  const time_t now = time(NULL);
+  if (m_height == 0 || now >= m_height_time + 30) // re-cache every 30 seconds
+  {
+    cryptonote::COMMAND_RPC_GET_HEIGHT::request req = AUTO_VAL_INIT(req);
+    cryptonote::COMMAND_RPC_GET_HEIGHT::response res = AUTO_VAL_INIT(res);
+
+    m_daemon_rpc_mutex.lock();
+    bool r = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/getheight", req, res, m_http_client);
+    m_daemon_rpc_mutex.unlock();
+    CHECK_AND_ASSERT_MES(r, std::string(), "Failed to connect to daemon");
+    CHECK_AND_ASSERT_MES(res.status != CORE_RPC_STATUS_BUSY, res.status, "Failed to connect to daemon");
+    CHECK_AND_ASSERT_MES(res.status == CORE_RPC_STATUS_OK, res.status, "Failed to get current blockchain height");
+    m_height = res.height;
+    m_height_time = now;
+  }
+  height = m_height;
+  return boost::optional<std::string>();
+}
+
+void NodeRPCProxy::set_height(uint64_t h)
+{
+  m_height = h;
+}
+
+boost::optional<std::string> NodeRPCProxy::get_earliest_height(uint8_t version, uint64_t &earliest_height)
+{
+  if (m_earliest_height[version] == 0)
+  {
+    epee::json_rpc::request<cryptonote::COMMAND_RPC_HARD_FORK_INFO::request> req_t = AUTO_VAL_INIT(req_t);
+    epee::json_rpc::response<cryptonote::COMMAND_RPC_HARD_FORK_INFO::response, std::string> resp_t = AUTO_VAL_INIT(resp_t);
+
+    m_daemon_rpc_mutex.lock();
+    req_t.jsonrpc = "2.0";
+    req_t.id = epee::serialization::storage_entry(0);
+    req_t.method = "hard_fork_info";
+    req_t.params.version = version;
+    bool r = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/json_rpc", req_t, resp_t, m_http_client);
+    m_daemon_rpc_mutex.unlock();
+    CHECK_AND_ASSERT_MES(r, std::string(), "Failed to connect to daemon");
+    CHECK_AND_ASSERT_MES(resp_t.result.status != CORE_RPC_STATUS_BUSY, resp_t.result.status, "Failed to connect to daemon");
+    CHECK_AND_ASSERT_MES(resp_t.result.status == CORE_RPC_STATUS_OK, resp_t.result.status, "Failed to get hard fork status");
+    m_earliest_height[version] = resp_t.result.earliest_height;
+  }
+
+  earliest_height = m_earliest_height[version];
+  return boost::optional<std::string>();
+}
+
+boost::optional<std::string> NodeRPCProxy::get_dynamic_per_kb_fee_estimate(uint64_t grace_blocks, uint64_t &fee)
+{
+  uint64_t height;
+
+  boost::optional<std::string> result = get_height(height);
+  if (result)
+    return result;
+
+  if (m_dynamic_per_kb_fee_estimate_cached_height != height || m_dynamic_per_kb_fee_estimate_grace_blocks != grace_blocks)
+  {
+    epee::json_rpc::request<cryptonote::COMMAND_RPC_GET_PER_KB_FEE_ESTIMATE::request> req_t = AUTO_VAL_INIT(req_t);
+    epee::json_rpc::response<cryptonote::COMMAND_RPC_GET_PER_KB_FEE_ESTIMATE::response, std::string> resp_t = AUTO_VAL_INIT(resp_t);
+
+    m_daemon_rpc_mutex.lock();
+    req_t.jsonrpc = "2.0";
+    req_t.id = epee::serialization::storage_entry(0);
+    req_t.method = "get_fee_estimate";
+    req_t.params.grace_blocks = grace_blocks;
+    bool r = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/json_rpc", req_t, resp_t, m_http_client);
+    m_daemon_rpc_mutex.unlock();
+    CHECK_AND_ASSERT_MES(r, std::string(), "Failed to connect to daemon");
+    CHECK_AND_ASSERT_MES(resp_t.result.status != CORE_RPC_STATUS_BUSY, resp_t.result.status, "Failed to connect to daemon");
+    CHECK_AND_ASSERT_MES(resp_t.result.status == CORE_RPC_STATUS_OK, resp_t.result.status, "Failed to get fee estimate");
+    m_dynamic_per_kb_fee_estimate = resp_t.result.fee;
+    m_dynamic_per_kb_fee_estimate_cached_height = height;
+    m_dynamic_per_kb_fee_estimate_grace_blocks = grace_blocks;
+  }
+
+  fee = m_dynamic_per_kb_fee_estimate;
+  return boost::optional<std::string>();
+}
+
+}
diff --git a/src/wallet/node_rpc_proxy.h b/src/wallet/node_rpc_proxy.h
new file mode 100644
index 000000000..1ae716dab
--- /dev/null
+++ b/src/wallet/node_rpc_proxy.h
@@ -0,0 +1,65 @@
+// Copyright (c) 2017, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include <string>
+#include <boost/thread/mutex.hpp>
+#include "include_base_utils.h"
+#include "net/http_client.h"
+
+namespace tools
+{
+
+class NodeRPCProxy
+{
+public:
+  NodeRPCProxy(epee::net_utils::http::http_simple_client &http_client, boost::mutex &mutex):
+    m_http_client(http_client), m_daemon_rpc_mutex(mutex) { init(""); }
+
+  void init(const std::string &daemon_address);
+
+  boost::optional<std::string> get_height(uint64_t &height);
+  void set_height(uint64_t h);
+  boost::optional<std::string> get_earliest_height(uint8_t version, uint64_t &earliest_height);
+  boost::optional<std::string> get_dynamic_per_kb_fee_estimate(uint64_t grace_blocks, uint64_t &fee);
+
+private:
+  std::string m_daemon_address;
+  epee::net_utils::http::http_simple_client &m_http_client;
+  boost::mutex &m_daemon_rpc_mutex;
+
+  uint64_t m_height;
+  time_t m_height_time;
+  uint64_t m_earliest_height[256];
+  uint64_t m_dynamic_per_kb_fee_estimate;
+  uint64_t m_dynamic_per_kb_fee_estimate_cached_height;
+  uint64_t m_dynamic_per_kb_fee_estimate_grace_blocks;
+};
+
+}
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index 8badebbfa..c08b16a5f 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -396,6 +396,19 @@ std::unique_ptr<tools::wallet2> generate_from_json(const std::string& json_file,
   return nullptr;
 }
 
+static void throw_on_rpc_response_error(const boost::optional<std::string> &status, const char *method)
+{
+  // no error
+  if (!status)
+    return;
+
+  // empty string -> not connection
+  THROW_WALLET_EXCEPTION_IF(status->empty(), tools::error::no_connection_to_daemon, method);
+
+  THROW_WALLET_EXCEPTION_IF(*status == CORE_RPC_STATUS_BUSY, tools::error::daemon_busy, method);
+  THROW_WALLET_EXCEPTION_IF(*status != CORE_RPC_STATUS_OK, tools::error::wallet_generic_rpc_error, method, *status);
+}
+
 } //namespace
 
 namespace tools
@@ -473,6 +486,7 @@ void wallet2::init(const std::string& daemon_address, uint64_t upper_transaction
 {
   m_upper_transaction_size_limit = upper_transaction_size_limit;
   m_daemon_address = daemon_address;
+  m_node_rpc_proxy.init(m_daemon_address);
 }
 //----------------------------------------------------------------------------------------------------
 bool wallet2::is_deterministic() const
@@ -1643,7 +1657,10 @@ void wallet2::refresh(uint64_t start_height, uint64_t & blocks_fetched, bool& re
       blocks_fetched += added_blocks;
       pull_thread.join();
       if(blocks_start_height == next_blocks_start_height)
+      {
+        m_node_rpc_proxy.set_height(m_blockchain.size());
         break;
+      }
 
       // switch to the new blocks from the daemon
       blocks_start_height = next_blocks_start_height;
@@ -3259,20 +3276,12 @@ uint64_t wallet2::get_fee_multiplier(uint32_t priority, bool use_new_fee) const
 //----------------------------------------------------------------------------------------------------
 uint64_t wallet2::get_dynamic_per_kb_fee_estimate()
 {
-  epee::json_rpc::request<cryptonote::COMMAND_RPC_GET_PER_KB_FEE_ESTIMATE::request> req_t = AUTO_VAL_INIT(req_t);
-  epee::json_rpc::response<cryptonote::COMMAND_RPC_GET_PER_KB_FEE_ESTIMATE::response, std::string> resp_t = AUTO_VAL_INIT(resp_t);
-
-  m_daemon_rpc_mutex.lock();
-  req_t.jsonrpc = "2.0";
-  req_t.id = epee::serialization::storage_entry(0);
-  req_t.method = "get_fee_estimate";
-  req_t.params.grace_blocks = FEE_ESTIMATE_GRACE_BLOCKS;
-  bool r = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/json_rpc", req_t, resp_t, m_http_client);
-  m_daemon_rpc_mutex.unlock();
-  CHECK_AND_ASSERT_THROW_MES(r, "Failed to connect to daemon");
-  CHECK_AND_ASSERT_THROW_MES(resp_t.result.status != CORE_RPC_STATUS_BUSY, "Failed to connect to daemon");
-  CHECK_AND_ASSERT_THROW_MES(resp_t.result.status == CORE_RPC_STATUS_OK, "Failed to get fee estimate");
-  return resp_t.result.fee;
+  uint64_t fee;
+  boost::optional<std::string> result = m_node_rpc_proxy.get_dynamic_per_kb_fee_estimate(FEE_ESTIMATE_GRACE_BLOCKS, fee);
+  if (!result)
+    return fee;
+  LOG_PRINT_L1("Failed to query per kB fee, using " << print_money(FEE_PER_KB));
+  return FEE_PER_KB;
 }
 //----------------------------------------------------------------------------------------------------
 uint64_t wallet2::get_per_kb_fee()
@@ -3280,15 +3289,8 @@ uint64_t wallet2::get_per_kb_fee()
   bool use_dyn_fee = use_fork_rules(HF_VERSION_DYNAMIC_FEE, -720 * 1);
   if (!use_dyn_fee)
     return FEE_PER_KB;
-  try
-  {
-    return get_dynamic_per_kb_fee_estimate();
-  }
-  catch (...)
-  {
-    LOG_PRINT_L1("Failed to query per kB fee, using " << print_money(FEE_PER_KB));
-    return FEE_PER_KB;
-  }
+
+  return get_dynamic_per_kb_fee_estimate();
 }
 //----------------------------------------------------------------------------------------------------
 // separated the call(s) to wallet2::transfer into their own function
@@ -3400,8 +3402,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions(std::vector<crypto
   }
 }
 
-template<typename entry>
-void wallet2::get_outs(std::vector<std::vector<entry>> &outs, const std::list<size_t> &selected_transfers, size_t fake_outputs_count)
+void wallet2::get_outs(std::vector<std::vector<tools::wallet2::get_outs_entry>> &outs, const std::list<size_t> &selected_transfers, size_t fake_outputs_count)
 {
   LOG_PRINT_L2("fake_outputs_count: " << fake_outputs_count);
   outs.clear();
@@ -3492,6 +3493,7 @@ void wallet2::get_outs(std::vector<std::vector<entry>> &outs, const std::list<si
         uint64_t num_found = 1;
         seen_indices.emplace(td.m_global_output_index);
         req.outputs.push_back({amount, td.m_global_output_index});
+        LOG_PRINT_L1("Selecting real output: " << td.m_global_output_index << " for " << print_money(amount));
 
         // while we still need more mixins
         while (num_found < requested_outputs_count)
@@ -3563,7 +3565,7 @@ void wallet2::get_outs(std::vector<std::vector<entry>> &outs, const std::list<si
     {
       const transfer_details &td = m_transfers[idx];
       size_t requested_outputs_count = base_requested_outputs_count + (td.is_rct() ? CRYPTONOTE_MINED_MONEY_UNLOCK_WINDOW - CRYPTONOTE_DEFAULT_TX_SPENDABLE_AGE : 0);
-      outs.push_back(std::vector<entry>());
+      outs.push_back(std::vector<get_outs_entry>());
       outs.back().reserve(fake_outputs_count + 1);
       const rct::key mask = td.is_rct() ? rct::commit(td.amount(), td.m_mask) : rct::zeroCommit(td.amount());
 
@@ -3616,7 +3618,7 @@ void wallet2::get_outs(std::vector<std::vector<entry>> &outs, const std::list<si
       else
       {
         // sort the subsection, so any spares are reset in order
-        std::sort(outs.back().begin(), outs.back().end(), [](const entry &a, const entry &b) { return std::get<0>(a) < std::get<0>(b); });
+        std::sort(outs.back().begin(), outs.back().end(), [](const get_outs_entry &a, const get_outs_entry &b) { return std::get<0>(a) < std::get<0>(b); });
       }
       base += requested_outputs_count;
     }
@@ -3627,7 +3629,7 @@ void wallet2::get_outs(std::vector<std::vector<entry>> &outs, const std::list<si
     for (size_t idx: selected_transfers)
     {
       const transfer_details &td = m_transfers[idx];
-      std::vector<entry> v;
+      std::vector<get_outs_entry> v;
       const rct::key mask = td.is_rct() ? rct::commit(td.amount(), td.m_mask) : rct::zeroCommit(td.amount());
       v.push_back(std::make_tuple(td.m_global_output_index, boost::get<txout_to_key>(td.m_tx.vout[td.m_internal_output_index].target).key, mask));
       outs.push_back(v);
@@ -3636,7 +3638,8 @@ void wallet2::get_outs(std::vector<std::vector<entry>> &outs, const std::list<si
 }
 
 template<typename T>
-void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_entry>& dsts, const std::list<size_t> selected_transfers, size_t fake_outputs_count,
+void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_entry>& dsts, const std::list<size_t> selected_transfers, size_t fake_outputs_count, 
+  std::vector<std::vector<tools::wallet2::get_outs_entry>> &outs,
   uint64_t unlock_time, uint64_t fee, const std::vector<uint8_t>& extra, T destination_split_strategy, const tx_dust_policy& dust_policy, cryptonote::transaction& tx, pending_tx &ptx)
 {
   using namespace cryptonote;
@@ -3666,11 +3669,11 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
   LOG_PRINT_L2("wanted " << print_money(needed_money) << ", found " << print_money(found_money) << ", fee " << print_money(fee));
   THROW_WALLET_EXCEPTION_IF(found_money < needed_money, error::not_enough_money, found_money, needed_money - fee, fee);
 
-  typedef std::tuple<uint64_t, crypto::public_key, rct::key> entry;
-  std::vector<std::vector<entry>> outs;
-  get_outs(outs, selected_transfers, fake_outputs_count); // may throw
+  if (outs.empty())
+    get_outs(outs, selected_transfers, fake_outputs_count); // may throw
 
   //prepare inputs
+  LOG_PRINT_L2("preparing outputs");
   typedef cryptonote::tx_source_entry::output_entry tx_output_entry;
   size_t i = 0, out_index = 0;
   std::vector<cryptonote::tx_source_entry> sources;
@@ -3713,6 +3716,7 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
     detail::print_source_entry(src);
     ++out_index;
   }
+  LOG_PRINT_L2("outputs prepared");
 
   cryptonote::tx_destination_entry change_dts = AUTO_VAL_INIT(change_dts);
   if (needed_money < found_money)
@@ -3735,7 +3739,9 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
   }
 
   crypto::secret_key tx_key;
+  LOG_PRINT_L2("constructing tx");
   bool r = cryptonote::construct_tx_and_get_tx_key(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key);
+  LOG_PRINT_L2("constructed tx, r="<<r);
   THROW_WALLET_EXCEPTION_IF(!r, error::tx_not_constructed, sources, splitted_dsts, unlock_time, m_testnet);
   THROW_WALLET_EXCEPTION_IF(upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, upper_transaction_size_limit);
 
@@ -3771,9 +3777,11 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
   ptx.construction_data.unlock_time = unlock_time;
   ptx.construction_data.use_rct = false;
   ptx.construction_data.dests = dsts;
+  LOG_PRINT_L2("transfer_selected done");
 }
 
 void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry> dsts, const std::list<size_t> selected_transfers, size_t fake_outputs_count,
+  std::vector<std::vector<tools::wallet2::get_outs_entry>> &outs,
   uint64_t unlock_time, uint64_t fee, const std::vector<uint8_t>& extra, cryptonote::transaction& tx, pending_tx &ptx)
 {
   using namespace cryptonote;
@@ -3782,7 +3790,7 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
 
   uint64_t upper_transaction_size_limit = get_upper_tranaction_size_limit();
   uint64_t needed_money = fee;
-  LOG_PRINT_L2("transfer: starting with fee " << print_money (needed_money));
+  LOG_PRINT_L2("transfer_selected_rct: starting with fee " << print_money (needed_money));
   LOG_PRINT_L0("selected transfers: ");
   for (auto t: selected_transfers)
     LOG_PRINT_L2("  " << t);
@@ -3806,11 +3814,11 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
   LOG_PRINT_L2("wanted " << print_money(needed_money) << ", found " << print_money(found_money) << ", fee " << print_money(fee));
   THROW_WALLET_EXCEPTION_IF(found_money < needed_money, error::not_enough_money, found_money, needed_money - fee, fee);
 
-  typedef std::tuple<uint64_t, crypto::public_key, rct::key> entry;
-  std::vector<std::vector<entry>> outs;
-  get_outs(outs, selected_transfers, fake_outputs_count); // may throw
+  if (outs.empty())
+    get_outs(outs, selected_transfers, fake_outputs_count); // may throw
 
   //prepare inputs
+  LOG_PRINT_L2("preparing outputs");
   size_t i = 0, out_index = 0;
   std::vector<cryptonote::tx_source_entry> sources;
   BOOST_FOREACH(size_t idx, selected_transfers)
@@ -3853,6 +3861,7 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
     detail::print_source_entry(src);
     ++out_index;
   }
+  LOG_PRINT_L2("outputs prepared");
 
   // we still keep a copy, since we want to keep dsts free of change for user feedback purposes
   std::vector<cryptonote::tx_destination_entry> splitted_dsts = dsts;
@@ -3864,9 +3873,11 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
     // the sender with a 0 amount output. We send a 0 amount in order to avoid
     // letting the destination be able to work out which of the inputs is the
     // real one in our rings
+    LOG_PRINT_L2("generating dummy address for 0 change");
     cryptonote::account_base dummy;
     dummy.generate();
     change_dts.addr = dummy.get_keys().m_account_address;
+    LOG_PRINT_L2("generated dummy address for 0 change");
   }
   else
   {
@@ -3875,10 +3886,13 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
   splitted_dsts.push_back(change_dts);
 
   crypto::secret_key tx_key;
+  LOG_PRINT_L2("constructing tx");
   bool r = cryptonote::construct_tx_and_get_tx_key(m_account.get_keys(), sources, splitted_dsts, extra, tx, unlock_time, tx_key, true);
+  LOG_PRINT_L2("constructed tx, r="<<r);
   THROW_WALLET_EXCEPTION_IF(!r, error::tx_not_constructed, sources, dsts, unlock_time, m_testnet);
   THROW_WALLET_EXCEPTION_IF(upper_transaction_size_limit <= get_object_blobsize(tx), error::tx_too_big, tx, upper_transaction_size_limit);
 
+  LOG_PRINT_L2("gathering key images");
   std::string key_images;
   bool all_are_txin_to_key = std::all_of(tx.vin.begin(), tx.vin.end(), [&](const txin_v& s_e) -> bool
   {
@@ -3887,6 +3901,7 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
     return true;
   });
   THROW_WALLET_EXCEPTION_IF(!all_are_txin_to_key, error::unexpected_txin_type, tx);
+  LOG_PRINT_L2("gathered key images");
 
   ptx.key_images = key_images;
   ptx.fee = fee;
@@ -3905,6 +3920,7 @@ void wallet2::transfer_selected_rct(std::vector<cryptonote::tx_destination_entry
   ptx.construction_data.unlock_time = unlock_time;
   ptx.construction_data.use_rct = true;
   ptx.construction_data.dests = dsts;
+  LOG_PRINT_L2("transfer_selected_rct done");
 }
 
 static size_t estimate_rct_tx_size(int n_inputs, int mixin, int n_outputs)
@@ -4106,12 +4122,14 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
   accumulated_change = 0;
   adding_fee = false;
   needed_fee = 0;
+  std::vector<std::vector<tools::wallet2::get_outs_entry>> outs;
 
   // for rct, since we don't see the amounts, we will try to make all transactions
   // look the same, with 1 or 2 inputs, and 2 outputs. One input is preferable, as
   // this prevents linking to another by provenance analysis, but two is ok if we
   // try to pick outputs not from the same block. We will get two outputs, one for
   // the destination, and one for change.
+  LOG_PRINT_L2("checking preferred");
   std::vector<size_t> prefered_inputs;
   uint64_t rct_outs_needed = 2 * (fake_outs_count + 1);
   rct_outs_needed += 100; // some fudge factor since we don't know how many are locked
@@ -4128,6 +4146,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
       LOG_PRINT_L1("Found prefered rct inputs for rct tx: " << s);
     }
   }
+  LOG_PRINT_L2("done checking preferred");
 
   // while:
   // - we have something to send
@@ -4161,6 +4180,9 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
     uint64_t available_amount = td.amount();
     accumulated_outputs += available_amount;
 
+    // clear any fake outs we'd already gathered, since we'll need a new set
+    outs.clear();
+
     if (adding_fee)
     {
       LOG_PRINT_L2("We need more fee, adding it to fee");
@@ -4217,10 +4239,10 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
       LOG_PRINT_L2("Trying to create a tx now, with " << tx.dsts.size() << " destinations and " <<
         tx.selected_transfers.size() << " outputs");
       if (use_rct)
-        transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+        transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
           test_tx, test_ptx);
       else
-        transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+        transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
           detail::digit_split_strategy, tx_dust_policy(::config::DEFAULT_DUST_THRESHOLD), test_tx, test_ptx);
       auto txBlob = t_serializable_object_to_blob(test_ptx.tx);
       needed_fee = calculate_fee(fee_per_kb, txBlob, fee_multiplier);
@@ -4260,10 +4282,10 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
         LOG_PRINT_L2("We made a tx, adjusting fee and saving it");
         do {
           if (use_rct)
-            transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+            transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
               test_tx, test_ptx);
           else
-            transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+            transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
               detail::digit_split_strategy, tx_dust_policy(::config::DEFAULT_DUST_THRESHOLD), test_tx, test_ptx);
           txBlob = t_serializable_object_to_blob(test_ptx.tx);
           needed_fee = calculate_fee(fee_per_kb, txBlob, fee_multiplier);
@@ -4351,6 +4373,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_from(const crypton
   std::vector<TX> txes;
   uint64_t needed_fee, available_for_fee = 0;
   uint64_t upper_transaction_size_limit = get_upper_tranaction_size_limit();
+  std::vector<std::vector<get_outs_entry>> outs;
 
   const bool use_rct = fake_outs_count > 0 && use_fork_rules(4, 0);
   const bool use_new_fee  = use_fork_rules(3, -720 * 14);
@@ -4386,6 +4409,9 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_from(const crypton
     uint64_t available_amount = td.amount();
     accumulated_outputs += available_amount;
 
+    // clear any fake outs we'd already gathered, since we'll need a new set
+    outs.clear();
+
     // here, check if we need to sent tx and start a new one
     LOG_PRINT_L2("Considering whether to create a tx now, " << tx.selected_transfers.size() << " inputs, tx limit "
       << upper_transaction_size_limit);
@@ -4407,10 +4433,10 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_from(const crypton
       LOG_PRINT_L2("Trying to create a tx now, with " << tx.dsts.size() << " destinations and " <<
         tx.selected_transfers.size() << " outputs");
       if (use_rct)
-        transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+        transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
           test_tx, test_ptx);
       else
-        transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+        transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
           detail::digit_split_strategy, tx_dust_policy(::config::DEFAULT_DUST_THRESHOLD), test_tx, test_ptx);
       auto txBlob = t_serializable_object_to_blob(test_ptx.tx);
       needed_fee = calculate_fee(fee_per_kb, txBlob, fee_multiplier);
@@ -4424,10 +4450,10 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_from(const crypton
         LOG_PRINT_L2("We made a tx, adjusting fee and saving it");
         tx.dsts[0].amount = available_for_fee - needed_fee;
         if (use_rct)
-          transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+          transfer_selected_rct(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
             test_tx, test_ptx);
         else
-          transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
+          transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, outs, unlock_time, needed_fee, extra,
             detail::digit_split_strategy, tx_dust_policy(::config::DEFAULT_DUST_THRESHOLD), test_tx, test_ptx);
         txBlob = t_serializable_object_to_blob(test_ptx.tx);
         needed_fee = calculate_fee(fee_per_kb, txBlob, fee_multiplier);
@@ -4489,39 +4515,19 @@ uint64_t wallet2::unlocked_dust_balance(const tx_dust_policy &dust_policy) const
 //----------------------------------------------------------------------------------------------------
 void wallet2::get_hard_fork_info(uint8_t version, uint64_t &earliest_height)
 {
-  epee::json_rpc::request<cryptonote::COMMAND_RPC_HARD_FORK_INFO::request> req_t = AUTO_VAL_INIT(req_t);
-  epee::json_rpc::response<cryptonote::COMMAND_RPC_HARD_FORK_INFO::response, std::string> resp_t = AUTO_VAL_INIT(resp_t);
-
-  m_daemon_rpc_mutex.lock();
-  req_t.jsonrpc = "2.0";
-  req_t.id = epee::serialization::storage_entry(0);
-  req_t.method = "hard_fork_info";
-  req_t.params.version = version;
-  bool r = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/json_rpc", req_t, resp_t, m_http_client);
-  m_daemon_rpc_mutex.unlock();
-  CHECK_AND_ASSERT_THROW_MES(r, "Failed to connect to daemon");
-  CHECK_AND_ASSERT_THROW_MES(resp_t.result.status != CORE_RPC_STATUS_BUSY, "Failed to connect to daemon");
-  CHECK_AND_ASSERT_THROW_MES(resp_t.result.status == CORE_RPC_STATUS_OK, "Failed to get hard fork status");
-
-  earliest_height = resp_t.result.earliest_height;
+  boost::optional<std::string> result = m_node_rpc_proxy.get_earliest_height(version, earliest_height);
+  throw_on_rpc_response_error(result, "get_hard_fork_info");
 }
 //----------------------------------------------------------------------------------------------------
 bool wallet2::use_fork_rules(uint8_t version, int64_t early_blocks)
 {
-  cryptonote::COMMAND_RPC_GET_HEIGHT::request req = AUTO_VAL_INIT(req);
-  cryptonote::COMMAND_RPC_GET_HEIGHT::response res = AUTO_VAL_INIT(res);
-
-  m_daemon_rpc_mutex.lock();
-  bool r = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/getheight", req, res, m_http_client);
-  m_daemon_rpc_mutex.unlock();
-  CHECK_AND_ASSERT_MES(r, false, "Failed to connect to daemon");
-  CHECK_AND_ASSERT_MES(res.status != CORE_RPC_STATUS_BUSY, false, "Failed to connect to daemon");
-  CHECK_AND_ASSERT_MES(res.status == CORE_RPC_STATUS_OK, false, "Failed to get current blockchain height");
+  uint64_t height, earliest_height;
+  boost::optional<std::string> result = m_node_rpc_proxy.get_height(height);
+  throw_on_rpc_response_error(result, "get_info");
+  result = m_node_rpc_proxy.get_earliest_height(version, earliest_height);
+  throw_on_rpc_response_error(result, "get_hard_fork_info");
 
-  uint64_t earliest_height;
-  get_hard_fork_info(version, earliest_height); // can throw
-
-  bool close_enough = res.height >=  earliest_height - early_blocks; // start using the rules that many blocks beforehand
+  bool close_enough = height >=  earliest_height - early_blocks; // start using the rules that many blocks beforehand
   if (close_enough)
     LOG_PRINT_L2("Using v" << (unsigned)version << " rules");
   else
@@ -4710,34 +4716,17 @@ std::string wallet2::get_daemon_address() const
 
 uint64_t wallet2::get_daemon_blockchain_height(string &err)
 {
-  // XXX: DRY violation. copy-pasted from simplewallet.cpp:get_daemon_blockchain_height()
-  //      consider to move it from simplewallet to wallet2 ?
-  COMMAND_RPC_GET_HEIGHT::request req;
-  COMMAND_RPC_GET_HEIGHT::response res = boost::value_initialized<COMMAND_RPC_GET_HEIGHT::response>();
-  m_daemon_rpc_mutex.lock();
-  bool ok = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/getheight", req, res, m_http_client);
-  m_daemon_rpc_mutex.unlock();
-  // XXX: DRY violation. copy-pasted from simplewallet.cpp:interpret_rpc_response()
-  if (ok)
-  {
-    if (res.status == CORE_RPC_STATUS_BUSY)
-    {
-      err = "daemon is busy. Please try again later.";
-    }
-    else if (res.status != CORE_RPC_STATUS_OK)
-    {
-      err = res.status;
-    }
-    else // success, cleaning up error message
-    {
-      err = "";
-    }
-  }
-  else
+  uint64_t height;
+
+  boost::optional<std::string> result = m_node_rpc_proxy.get_height(height);
+  if (result)
   {
-    err = "possibly lost connection to daemon";
+    err = *result;
+    return 0;
   }
-  return res.height;
+
+  err = "";
+  return height;
 }
 
 uint64_t wallet2::get_daemon_blockchain_target_height(string &err)
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index b5cc56e56..629011800 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -54,6 +54,7 @@
 
 #include "wallet_errors.h"
 #include "password_container.h"
+#include "node_rpc_proxy.h"
 
 #include <iostream>
 
@@ -103,7 +104,7 @@ namespace tools
     };
 
   private:
-    wallet2(const wallet2&) : m_run(true), m_callback(0), m_testnet(false), m_always_confirm_transfers(true), m_print_ring_members(false), m_store_tx_info(true), m_default_mixin(0), m_default_priority(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0), m_confirm_missing_payment_id(true) {}
+    wallet2(const wallet2&) : m_run(true), m_callback(0), m_testnet(false), m_always_confirm_transfers(true), m_print_ring_members(false), m_store_tx_info(true), m_default_mixin(0), m_default_priority(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0), m_confirm_missing_payment_id(true), m_node_rpc_proxy(m_http_client, m_daemon_rpc_mutex) {}
 
   public:
     static const char* tr(const char* str);// { return i18n_translate(str, "cryptonote::simple_wallet"); }
@@ -124,7 +125,7 @@ namespace tools
     //! Uses stdin and stdout. Returns a wallet2 and password for wallet with no file if no errors.
     static std::pair<std::unique_ptr<wallet2>, password_container> make_new(const boost::program_options::variables_map& vm);
 
-    wallet2(bool testnet = false, bool restricted = false) : m_run(true), m_callback(0), m_testnet(testnet), m_always_confirm_transfers(true), m_print_ring_members(false), m_store_tx_info(true), m_default_mixin(0), m_default_priority(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0), m_confirm_missing_payment_id(true), m_restricted(restricted), is_old_file_format(false) {}
+    wallet2(bool testnet = false, bool restricted = false) : m_run(true), m_callback(0), m_testnet(testnet), m_always_confirm_transfers(true), m_print_ring_members(false), m_store_tx_info(true), m_default_mixin(0), m_default_priority(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0), m_confirm_missing_payment_id(true), m_restricted(restricted), is_old_file_format(false), m_node_rpc_proxy(m_http_client, m_daemon_rpc_mutex) {}
     struct transfer_details
     {
       uint64_t m_block_height;
@@ -275,6 +276,8 @@ namespace tools
       std::string m_description;   
     };
 
+    typedef std::tuple<uint64_t, crypto::public_key, rct::key> get_outs_entry;
+
     /*!
      * \brief Generates a wallet or restores one.
      * \param  wallet_        Name of wallet file
@@ -387,8 +390,10 @@ namespace tools
     void transfer(const std::vector<cryptonote::tx_destination_entry>& dsts, const size_t fake_outputs_count, const std::vector<size_t> &unused_transfers_indices, uint64_t unlock_time, uint64_t fee, const std::vector<uint8_t>& extra, cryptonote::transaction& tx, pending_tx& ptx, bool trusted_daemon);
     template<typename T>
     void transfer_selected(const std::vector<cryptonote::tx_destination_entry>& dsts, const std::list<size_t> selected_transfers, size_t fake_outputs_count,
+      std::vector<std::vector<tools::wallet2::get_outs_entry>> &outs,
       uint64_t unlock_time, uint64_t fee, const std::vector<uint8_t>& extra, T destination_split_strategy, const tx_dust_policy& dust_policy, cryptonote::transaction& tx, pending_tx &ptx);
     void transfer_selected_rct(std::vector<cryptonote::tx_destination_entry> dsts, const std::list<size_t> selected_transfers, size_t fake_outputs_count,
+      std::vector<std::vector<tools::wallet2::get_outs_entry>> &outs,
       uint64_t unlock_time, uint64_t fee, const std::vector<uint8_t>& extra, cryptonote::transaction& tx, pending_tx &ptx);
 
     void commit_tx(pending_tx& ptx_vector);
@@ -607,8 +612,7 @@ namespace tools
     std::vector<size_t> pick_preferred_rct_inputs(uint64_t needed_money) const;
     void set_spent(size_t idx, uint64_t height);
     void set_unspent(size_t idx);
-    template<typename entry>
-    void get_outs(std::vector<std::vector<entry>> &outs, const std::list<size_t> &selected_transfers, size_t fake_outputs_count);
+    void get_outs(std::vector<std::vector<get_outs_entry>> &outs, const std::list<size_t> &selected_transfers, size_t fake_outputs_count);
     bool wallet_generate_key_image_helper(const cryptonote::account_keys& ack, const crypto::public_key& tx_public_key, size_t real_output_index, cryptonote::keypair& in_ephemeral, crypto::key_image& ki);
     crypto::public_key get_tx_pub_key_from_received_outs(const tools::wallet2::transfer_details &td) const;
 
@@ -652,6 +656,7 @@ namespace tools
     bool m_auto_refresh;
     uint64_t m_refresh_from_block_height;
     bool m_confirm_missing_payment_id;
+    NodeRPCProxy m_node_rpc_proxy;
   };
 }
 BOOST_CLASS_VERSION(tools::wallet2, 16)
diff --git a/src/wallet/wallet_errors.h b/src/wallet/wallet_errors.h
index 93e7c2ec3..785a72e4b 100644
--- a/src/wallet/wallet_errors.h
+++ b/src/wallet/wallet_errors.h
@@ -626,6 +626,18 @@ namespace tools
       std::string m_request;
     };
     //----------------------------------------------------------------------------------------------------
+    struct wallet_generic_rpc_error : public wallet_rpc_error
+    {
+      explicit wallet_generic_rpc_error(std::string&& loc, const std::string& request, const std::string& status)
+        : wallet_rpc_error(std::move(loc), std::string("error in ") + request + " RPC: " + status, request),
+        m_status(status)
+      {
+      }
+      const std::string& status() const { return m_status; }
+    private:
+      const std::string m_status;
+    };
+    //----------------------------------------------------------------------------------------------------
     struct daemon_busy : public wallet_rpc_error
     {
       explicit daemon_busy(std::string&& loc, const std::string& request)
diff --git a/src/wallet/wallet_rpc_server.cpp b/src/wallet/wallet_rpc_server.cpp
index bf2cba346..33e099ceb 100644
--- a/src/wallet/wallet_rpc_server.cpp
+++ b/src/wallet/wallet_rpc_server.cpp
@@ -396,6 +396,7 @@ namespace tools
     std::vector<cryptonote::tx_destination_entry> dsts;
     std::vector<uint8_t> extra;
 
+    LOG_PRINT_L3("on_transfer_split starts");
     if (m_wallet.restricted())
     {
       er.code = WALLET_RPC_ERROR_CODE_DENIED;
@@ -485,9 +486,13 @@ namespace tools
         mixin = 2;
       }
       std::vector<wallet2::pending_tx> ptx_vector;
+      LOG_PRINT_L2("on_transfer_split calling create_transactions_2");
       ptx_vector = m_wallet.create_transactions_2(dsts, mixin, req.unlock_time, req.priority, extra, req.trusted_daemon);
+      LOG_PRINT_L2("on_transfer_split called create_transactions_2");
 
+      LOG_PRINT_L2("on_transfer_split calling commit_txyy");
       m_wallet.commit_tx(ptx_vector);
+      LOG_PRINT_L2("on_transfer_split called commit_txyy");
 
       // populate response with tx hashes
       for (auto & ptx : ptx_vector)