Add external estimate fee query

libraries/plugins/peerplays_sidechain/CMakeLists.txt

@@ -16,6 +16,7 @@ add_library( peerplays_sidechain
              bitcoin/utils.cpp
              bitcoin/sign_bitcoin_transaction.cpp
              bitcoin/libbitcoin_client.cpp
+             bitcoin/estimate_fee_external.cpp
              common/rpc_client.cpp
              common/utils.cpp
              hive/asset.cpp

libraries/plugins/peerplays_sidechain/bitcoin/estimate_fee_external.cpp

@@ -0,0 +1,90 @@
+
+#include <graphene/peerplays_sidechain/bitcoin/estimate_fee_external.hpp>
+
+#include <boost/property_tree/json_parser.hpp>
+#include <boost/property_tree/ptree.hpp>
+
+#include <fc/log/logger.hpp>
+
+#include <iostream>
+
+namespace graphene {
+namespace peerplays_sidechain {
+
+static size_t writeFunction(void *ptr, size_t size, size_t nmemb, std::string *data) {
+   data->append((char *)ptr, size * nmemb);
+   return size * nmemb;
+}
+
+estimate_fee_external::estimate_fee_external() {
+   curl = curl_easy_init();
+}
+
+estimate_fee_external::~estimate_fee_external() {
+   curl_easy_cleanup(curl);
+}
+
+uint64_t estimate_fee_external::get_fee_external(uint16_t target_block) {
+
+   this->target_block = target_block;
+
+   uint64_t average_fee = 0;
+
+   for (auto &url_fee_parser : url_get_fee_parsers) {
+      response = get_response(url_fee_parser.first);
+      uint64_t fee = url_fee_parser.second();
+      average_fee = fee;
+   }
+
+   return 0;
+}
+
+std::string estimate_fee_external::get_response(std::string url) {
+
+   std::string response;
+   if (curl) {
+      curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
+      curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
+      curl_easy_setopt(curl, CURLOPT_USERPWD, "user:pass");
+      curl_easy_setopt(curl, CURLOPT_USERAGENT, "curl/7.42.0");
+      curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 50L);
+      curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);
+      curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeFunction);
+      curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);
+      curl_easy_perform(curl);
+   }
+   return response;
+}
+
+uint64_t estimate_fee_external::parse_and_get_fee_1() {
+   //"https://www.bitgo.com/api/v2/btc/tx/fee"
+
+   std::stringstream response_ss(response);
+   boost::property_tree::ptree response_pt;
+   boost::property_tree::read_json(response_ss, response_pt);
+
+   uint64_t founded_fee = 0;
+
+   for (const auto &tx_child : response_pt.get_child("feeByBlockTarget")) {
+      const auto &block_num = tx_child.first.data();
+      const auto &fee = tx_child.second.data();
+
+      founded_fee = std::stoi(fee);
+
+      if (std::stoi(block_num) > target_block) {
+         return founded_fee;
+      }
+
+      std::cout << "Block num: " << block_num << " Fee: " << fee << std::endl;
+   }
+}
+
+uint64_t estimate_fee_external::parse_and_get_fee_2() {
+   // TODO
+}
+
+uint64_t estimate_fee_external::parse_and_get_fee_3() {
+   // TODO
+}
+
+}} // namespace graphene::peerplays_sidechain

libraries/plugins/peerplays_sidechain/include/graphene/peerplays_sidechain/bitcoin/estimate_fee_external.hpp

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <curl/curl.h>
+
+#include <functional>
+#include <map>
+
+typedef std::function<uint64_t()> get_fee_func_type;
+
+namespace graphene { namespace peerplays_sidechain {
+
+class estimate_fee_external {
+public:
+   estimate_fee_external();
+   ~estimate_fee_external();
+   uint64_t get_fee_external(uint16_t target_block);
+
+private:
+   std::string get_response(std::string url);
+   // Here add your custom parser for external url. Take care of incremental name
+   // and populate the list of url_parsers bellow paired with the function
+   uint64_t parse_and_get_fee_1();
+   uint64_t parse_and_get_fee_2();
+   uint64_t parse_and_get_fee_3();
+
+   const std::map<std::string, get_fee_func_type> url_get_fee_parsers{
+         {"https://www.bitgo.com/api/v2/btc/tx/fee", std::bind(&estimate_fee_external::parse_and_get_fee_1, this)},
+         {"https://bitcoiner.live/api/fees/estimates/latest", std::bind(&estimate_fee_external::parse_and_get_fee_2, this)},
+         {"https://api.blockchain.info/mempool/fees", std::bind(&estimate_fee_external::parse_and_get_fee_3, this)}};
+
+   std::string response;
+   uint16_t target_block;
+   CURL *curl{nullptr};
+};
+
+}} // namespace graphene::peerplays_sidechain