leso-kn/dbus_gatt

GATT server library using the BlueZ dbus API.

CPP library to make BLE GATT server using BLUEZ DBus API

This library provides a easy way to make BLE GATT server, but do not provide bluetooth managment API bluetooth managment API

Implemented features

• GATT services
• GATT characteristics
  • Read
  • Write
  • Write Without response
  • Notify
• Device Property Changed events
  • Address
  • AddressType
  • Name
  • Alias
  • Paired
  • Trusted
  • Blocked
  • LegacyPairing
  • Connected
  • Adapter
  • ServicesResolved
  • RSSI

How to start

1. Write a code

   #include "dbus_gatt/dbus_gatt.h"
   
   class YourGATTAppName : public dbus_gatt::DBusGATT {
       YourGATTAppName(): dbus_gatt::DBusGATT("your-gatt-app-bus-name", "/your/gatt/app/bus/path") {
           Services(dbus_gatt::DBusGATT::Service(
               "your-gatt-app-service", // service name
               "00000001-0000-0000-0000-000000000001", // service uuid
               dbus_gatt::DBusGATT::ReadOnlyValueCharacteristic(
                   "test_read_only_value",
                   "00000002-0000-0000-0000-000000000001",
                   dbus_gatt::kCharacteristicFlagRead,
                   dbus_gatt::DBusGattVariantT(std::string("read only value"))
                   ),
               dbus_gatt::DBusGATT::Characteristic(
                   "test_char",
                   "00000003-0000-0000-0000-000000000001",
                   dbus_gatt::kCharacteristicFlagRead | dbus_gatt::kCharacteristicFlagWrite,
                   []() -> dbus_gatt::DBusGattVariantT {
                       return static_cast<int32_t>(some_value_);
                   },
                   [](const uint8_t* value, size_t size) {
                       // do something with data
                       return static_cast<int32_t>(0);
                   }
                   )
               )
           );
       }
   private:
       int32_t some_value_ = {0};
   };
   
   int main() {
   
       auto app = YourGATTAppName();
   
       app.start();
   
       // catch exit signall and call app.stop();
   
       return 0;
   }
   

2. Create D-Bus permissions config file

   example /etc/dbus-1/system.d/your-gatt-app-name.conf

   <!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN" "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
   <busconfig>
     <policy user="root">
       <allow own="your-gatt-app-bus-name"/>
       <allow send_destination="org.bluez"/>
     </policy>
     <policy at_console="true">
       <allow own="your-gatt-app-bus-name"/>
       <allow send_destination="org.bluez"/>
     </policy>
     <policy context="default">
     </policy>
   </busconfig>

3. Create your app service configuration file

   example /etc/systemd/system/your-gatt-app-name.service:

   [Unit]
   Description=your app description
   After=bluetooth.service
   
   [Install]
   WantedBy=multi-user.target
   
   [Service]
   
   ExecStartPre=
   ExecStartPre=-btmgmt -i 0 power off
   ExecStartPre=-btmgmt -i 0 bredr off
   ExecStartPre=-btmgmt -i 0 le on
   ExecStartPre=-btmgmt -i 0 connectable on
   ExecStartPre=-btmgmt -i 0 advertising on
   ExecStartPre=-btmgmt -i 0 power on
   
   ExecStart=/path/to/your/app
   Type=simple
   WorkingDirectory=/
   Restart=always
   RestartSec=15
   KillSignal=SIGTERM
   StandardError=syslog

4. Start your app service

   execute shell commands

   systemctl daemon-reload
   systemctl start your-gatt-app-name