Run the example

  1. Install and run the device gateway
  2. Download the C++ client library
  3. Copy the root certificate of the gateway to your working directory. As default, the certificate(ca.crt) resides in cert of the installation directory.
  4. The example uses CMake. You can change the CMakeLists.txt file as needed.

  5. Change the gateway and the device information in example/event/test/main.cpp as needed.

     // the path of the root certificate
 const std::string GATEWAY_CA_FILE = "../cert/gateway/ca.crt";

 // the address of the gateway
 const std::string GATEWAY_ADDR = "192.168.0.2";
 const int GATEWAY_PORT = 4000;
    
 // the ip address of the target device
 const std::string DEVICE_IP = "192.168.0.110";
 const int DEVICE_PORT = 51211;
 const bool USE_SSL = false;

  6. Build and run.

    • Windows

      cmake .

      Open testEvent.vcxproj in Visual Studio and build it.

      ./Debug/testEvent

    • Linux

      cmake .
make testEvent
./testEvent

1. Connect to the gateway and the device

The example assumes you use the device gateway. For the master gateway or other connection options, refer to the Connect or ConnectMaster examples.

  auto gatewayClient = std::make_shared<GatewayClient>();
  gatewayClient->Connect(GATEWAY_ADDR, GATEWAY_PORT, GATEWAY_CA_FILE);

  ConnectSvc connectSvc(gatewayClient->GetChannel());

  ConnectInfo connInfo;
  connInfo.set_ipaddr(DEVICE_IP);
  connInfo.set_port(DEVICE_PORT);
  connInfo.set_usessl(USE_SSL);

  uint32_t deviceID = 0;
  connectSvc.Connect(connInfo, &deviceID);

2. Initialize the event code map

Since V1.3, the event code map, event_code.json, is provided. You can use it in your application for looking up the short descriptions of event codes.

  #include <nlohmann/json.hpp>

  json codeMap_;

  void EventSvc::InitCodeMap(std::string filename) {
    std::ifstream mapFile(filename);
    mapFile >> codeMap_;
  }

  std::string EventSvc::GetEventString(uint32_t eventCode, uint32_t subCode) {
    char buf[256];

    for(int i = 0; i < codeMap_["entries"].size(); i++) {
      if(eventCode == codeMap_["entries"].at(i)["event_code"] && subCode == codeMap_["entries"].at(i)["sub_code"]) {
        return codeMap_["entries"].at(i)["desc"];
      }
    }

    sprintf(buf, "Unknown code(%#x)", eventCode | subCode);
    return buf;
  }

  eventSvc.InitCodeMap(CODE_MAP_FILE);

3. Receive realtime events

To receive realtime events from the devices, you have to do the followings.

  1. Enable monitoring on target devices.
  2. Subscribe to the event channel.
  3. Read the events from the channel.
  void handleEvent(std::unique_ptr<ClientReader<EventLog>> eventReader) {
    EventLog realtimeEvent;

    while (eventReader->Read(&realtimeEvent)) {
      std::cout << "[EVENT] " << realtimeEvent.ShortDebugString() << std::endl;
    }
  }

  svc.EnableMonitoring(deviceID);

  s_Context = std::make_shared<ClientContext>();
  auto eventReader(svc.Subscribe(s_Context.get(), EVENT_QUEUE_SIZE));

  s_MonitoringThread = std::thread(handleEvent, std::move(eventReader));

4. Read event logs

When reading event logs, you can specify the starting index and the maximum number of events.

  RepeatedPtrField<EventLog> events;
  svc.GetLog(deviceID, s_FirstEventID, MAX_NUM_EVENT, &events);

  for(int i = 0; i < events.size(); i++) {
    printEvent(svc, events[i]);
  }

Updated: