Update stats every 5 seconds via websocket

2 files changed, 43 insertions, 7 deletions

diff --git a/debian/changelog b/debian/changelog
index 7c0064f..5dda00e 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,6 +1,7 @@
 whiteboard (1.6) UNRELEASED; urgency=medium
 
   * Added stats.html
+  * Use boost strands instead of mutex
 
  -- Roland Reichwein <mail@reichwein.it>  Tue, 31 Jan 2023 18:22:42 +0100
 
diff --git a/whiteboard.cpp b/whiteboard.cpp
index 922bd37..2c8a47b 100644
--- a/whiteboard.cpp
+++ b/whiteboard.cpp
@@ -251,6 +251,45 @@ public:
                 });
  }
 
+ std::string stats_xml()
+ {
+  return make_xml({
+                  {"type", "stats" },
+                  {"dbsizegross", std::to_string(m_storage.dbsize_gross()) },
+                  {"dbsizenet", std::to_string(m_storage.dbsize_net()) },
+                  {"numberofdocuments", std::to_string(m_storage.getNumberOfDocuments()) },
+                  {"numberofconnections", std::to_string(m_registry.number_of_connections()) },
+                  }); 
+ }
+
+ void on_write_stats(std::shared_ptr<std::string> data, std::shared_ptr<boost::asio::const_buffer> buffer, boost::beast::error_code ec, std::size_t bytes_transferred)
+ {
+  boost::ignore_unused(bytes_transferred);
+
+  if (ec) {
+   std::cerr << "Error on session write stats: " << ec.message() << std::endl;
+  }
+ }
+
+ void stats_callback(const boost::system::error_code&)
+ {
+  auto data{std::make_shared<std::string>(stats_xml())};
+  auto buffer{std::make_shared<boost::asio::const_buffer>(data->data(), data->size())};
+  m_ws->async_write(*buffer, boost::asio::bind_executor(m_ws->next_layer().get_executor(),
+                                                        boost::beast::bind_front_handler(&session::on_write_stats, shared_from_this(), data, buffer)));
+
+  m_stats_timer->expires_at(m_stats_timer->expires_at() + boost::asio::chrono::seconds(5));
+  m_stats_timer->async_wait(boost::beast::bind_front_handler(&session::stats_callback, this));
+ }
+
+ void setup_stats_timer()
+ {
+  if (!m_stats_timer) {
+   m_stats_timer = std::make_shared<boost::asio::steady_timer>(m_ws->next_layer().get_executor(), boost::asio::chrono::seconds(5));
+   m_stats_timer->async_wait(boost::beast::bind_front_handler(&session::stats_callback, this));
+  }
+ }
+
  std::string handle_request(const std::string& request)
  {
   try {
@@ -339,13 +378,8 @@ public:
                     {"version", WHITEBOARD_VERSION }
                     }); 
    } else if (command == "getstats") {
-    return make_xml({
-                    {"type", "stats" },
-                    {"dbsizegross", std::to_string(m_storage.dbsize_gross()) },
-                    {"dbsizenet", std::to_string(m_storage.dbsize_net()) },
-                    {"numberofdocuments", std::to_string(m_storage.getNumberOfDocuments()) },
-                    {"numberofconnections", std::to_string(m_registry.number_of_connections()) },
-                    }); 
+    setup_stats_timer();
+    return stats_xml();
    } else {
     throw std::runtime_error("Bad command: "s + command);
    }
@@ -365,6 +399,7 @@ private:
  boost::beast::http::request<boost::beast::http::string_body> m_req;
  boost::beast::flat_buffer m_buffer;
 
+ std::shared_ptr<boost::asio::steady_timer> m_stats_timer{};
 };
 
 void Whiteboard::do_accept()