basic network info added to front page

https://github.com/moneroexamples/onion-monero-blockchain-explorer/issues/59

README.md

@@ -564,21 +564,22 @@ curl  -w "\n" -X GET "http://139.162.32.245:8081/api/networkinfo"
   "data": {
     "alt_blocks_count": 0,
     "block_size_limit": 600000,
-    "cumulative_difficulty": 2067724366624367,
+    "cumulative_difficulty": 2091549555696348,
-    "difficulty": 7530486740,
+    "difficulty": 7941560081,
-    "grey_peerlist_size": 4987,
+    "fee_per_kb": 303970000,
-    "hash_rate": 62754056,
+    "grey_peerlist_size": 4991,
-    "height": 1307537,
+    "hash_rate": 66179667,
+    "height": 1310423,
     "incoming_connections_count": 0,
-    "outgoing_connections_count": 8,
+    "outgoing_connections_count": 5,
-    "start_time": 1494473774,
+    "start_time": 1494822692,
     "status": "OK",
     "target": 120,
-    "target_height": 1307518,
+    "target_height": 0,
     "testnet": false,
-    "top_block_hash": "0726de5b86f431547fc64fc2c8e1c11d76843ada0561993ee540e4eee29d83c3",
+    "top_block_hash": "76f9e85d62415312758bc09e0b9b48fd2b005231ad1eee435a8081e551203f82",
-    "tx_count": 1210222,
+    "tx_count": 1219048,
-    "tx_pool_size": 5,
+    "tx_pool_size": 2,
     "white_peerlist_size": 1000
   },
   "status": "success"

src/monero_headers.h

@@ -14,6 +14,8 @@
 #define KEY_IMAGE_EXPORT_FILE_MAGIC "Monero key image export\002"
 #define OUTPUT_EXPORT_FILE_MAGIC "Monero output export\003"
 
+#define FEE_ESTIMATE_GRACE_BLOCKS 10 // estimate fee valid for that many blocks
+
 #include "release/version/version.h"
 
 #include "net/http_client.h"

src/page.h

@@ -394,6 +394,33 @@ namespace xmreg
         string
         index2(uint64_t page_no = 0, bool refresh_page = false)
         {
+
+            // we get network info, such as current hash rate
+            // but since this makes a rpc call to deamon, we make it as an async
+            // call. this way we dont have to wait with execution of the rest of the
+            // index2 method, until deamon gives as the required result.
+            std::future<json> network_info_ftr = std::async(std::launch::async, [&]
+            {
+                json j_info;
+
+                if (!get_monero_network_info(j_info))
+                {
+                    return json{};
+                }
+
+                uint64_t fee_estimated {0};
+
+                // get dynamic fee estimate from last 10 blocks
+                if (!get_dynamic_per_kb_fee_estimate(fee_estimated))
+                {
+                    return json{};
+                }
+
+                j_info["fee_per_kb"] = fee_estimated;
+
+                return j_info;
+            });
+
             //get current server timestamp
             server_timestamp = std::time(nullptr);
 
@@ -694,6 +721,42 @@ namespace xmreg
             context["cache_hits"]   = cache_hits;
             context["cache_misses"] = cache_misses;
 
+            // now time to check if we have our networkinfo from network_info future
+            // wait a bit (200 millisecond max) if not, just in case, but we dont wait more.
+            // if its not ready by now, forget about it.
+
+            std::future_status ftr_status = network_info_ftr.wait_for(
+                    std::chrono::milliseconds(200));
+
+            if (ftr_status == std::future_status::ready)
+            {
+                json j_network_info = network_info_ftr.get();
+
+                if (!j_network_info.empty())
+                {
+                    string difficulty;
+
+                    if (testnet)
+                    {
+                        difficulty = std::to_string(j_network_info["hash_rate"].get<uint64_t>()) + " H/s";
+                    }
+                    else
+                    {
+                        difficulty = fmt::format("{:0.3f} MH/s", j_network_info["hash_rate"].get<uint64_t>()/1.0e6);
+                    }
+
+                    context["network_info"] = mstch::map {
+                            {"difficulty", j_network_info["difficulty"].get<uint64_t>()},
+                            {"hash_rate" , difficulty},
+                            {"fee_per_kb", xmreg::xmr_amount_to_str(j_network_info["fee_per_kb"], "{:0.12f}")}
+                    };
+                }
+            }
+            else
+            {
+                cerr  << "network_info future not ready yet, skipping." << endl;
+            }
+
             // get memory pool rendered template
             string mempool_html = mempool(false, no_of_mempool_tx_of_frontpage);
 
@@ -4677,6 +4740,7 @@ namespace xmreg
 
             json j_info;
 
+            // get basic network info
             if (!get_monero_network_info(j_info))
             {
                 j_response["status"]  = "error";
@@ -4684,6 +4748,18 @@ namespace xmreg
                 return j_response;
             }
 
+            uint64_t fee_estimated {0};
+
+            // get dynamic fee estimate from last 10 blocks
+            if (!get_dynamic_per_kb_fee_estimate(fee_estimated))
+            {
+                j_response["status"]  = "error";
+                j_response["message"] = "Cant get dynamic fee esimate";
+                return j_response;
+            }
+
+            j_info["fee_per_kb"] = fee_estimated;
+
             j_data = j_info;
 
             j_response["status"]  = "success";
@@ -4717,6 +4793,7 @@ namespace xmreg
             return j_tx;
         }
 
+
         bool
         find_tx(const crypto::hash& tx_hash,
                 transaction& tx,
@@ -5498,6 +5575,25 @@ namespace xmreg
             return true;
         }
 
+        bool
+        get_dynamic_per_kb_fee_estimate(uint64_t& fee_estimated)
+        {
+
+            string error_msg;
+
+            if (!rpc.get_dynamic_per_kb_fee_estimate(
+                    FEE_ESTIMATE_GRACE_BLOCKS,
+                    fee_estimated, error_msg))
+            {
+                cerr << "rpc.get_dynamic_per_kb_fee_estimate failed" << endl;
+                return false;
+            }
+
+            (void) error_msg;
+
+            return true;
+        }
+
         string
         get_footer()
         {

src/rpccalls.cpp

@@ -207,4 +207,70 @@ rpccalls::get_network_info(COMMAND_RPC_GET_INFO::response& response)
 }
 
 
+bool
+rpccalls::get_dynamic_per_kb_fee_estimate(
+        uint64_t grace_blocks,
+        uint64_t& fee,
+        string& error_msg)
+{
+    epee::json_rpc::request<COMMAND_RPC_GET_PER_KB_FEE_ESTIMATE::request>
+            req_t = AUTO_VAL_INIT(req_t);
+    epee::json_rpc::response<COMMAND_RPC_GET_PER_KB_FEE_ESTIMATE::response, std::string>
+            resp_t = AUTO_VAL_INIT(resp_t);
+
+
+    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 {false};
+
+    std::lock_guard<std::mutex> guard(m_daemon_rpc_mutex);
+
+    {
+        if (!connect_to_monero_deamon())
+        {
+            cerr << "get_current_height: not connected to deamon" << endl;
+            return false;
+        }
+
+        r = epee::net_utils::invoke_http_json("/json_rpc",
+                                              req_t, resp_t,
+                                              m_http_client);
+    }
+
+    string err;
+
+
+    if (r)
+    {
+        if (resp_t.result.status == CORE_RPC_STATUS_BUSY)
+        {
+            err = "daemon is busy. Please try again later.";
+        }
+        else if (resp_t.result.status != CORE_RPC_STATUS_OK)
+        {
+            err = resp_t.result.status;
+        }
+
+        if (!err.empty())
+        {
+            cerr << "Error connecting to Monero deamon due to "
+                 << err << endl;
+            return false;
+        }
+    }
+    else
+    {
+        cerr << "Error connecting to Monero deamon at "
+             << deamon_url << endl;
+        return false;
+    }
+
+    fee = resp_t.result.fee;
+
+    return true;
+
+}
 }

src/rpccalls.h

@@ -52,6 +52,12 @@ public:
     bool
     get_network_info(COMMAND_RPC_GET_INFO::response& info);
 
+    bool
+    get_dynamic_per_kb_fee_estimate(
+            uint64_t grace_blocks,
+            uint64_t& fee,
+            string& error_msg);
+
 };
 
 

src/templates/index2.html

@@ -32,6 +32,18 @@
          {{/testnet}}
 
         </h3>
+
+
+    {{#network_info}}
+
+        <h3 style="font-size: 12px; margin-top: 10px">
+            Network difficulty: {{difficulty}}
+            | Hash rate: {{hash_rate}}
+            | Fee per kb: {{fee_per_kb}}
+        </h3>
+        {{/network_info}}
+
+
 </div>
 
     {{{mempool_info}}}
@@ -87,6 +99,7 @@
 
     </div>
 
+
 {{#show_cache_times}}
     <div class="center">
         <h6 style="margin-top: 1px;color:#949490">