How to connect to a Redis server using Ada

redis_client.adb

with GNAT.Sockets;
with Ada.Text_IO;
with Ada.Strings.Unbounded;
with Ada.Streams; use Ada.Streams;

procedure Redis_Client is
   package TIO renames Ada.Text_IO;
   package UBS renames Ada.Strings.Unbounded;

   Host : constant String := "127.0.0.1";
   Port_Number : GNAT.Sockets.Port_Type := 6379;

   Host_Entry : GNAT.Sockets.Host_Entry_Type :=
     GNAT.Sockets.Get_Host_By_Name (Host);

   Address : GNAT.Sockets.Sock_Addr_Type;
   Socket  : GNAT.Sockets.Socket_Type;

   function Redis_Call
     (Conn : in out GNAT.Sockets.Socket_Type;
      Cmd  :        String) return String
   is
      Channel : GNAT.Sockets.Stream_Access;
      Data    : Ada.Streams.Stream_Element_Array (1 .. 1024);
      Size    : Ada.Streams.Stream_Element_Offset;
      Ret     : Ada.Strings.Unbounded.Unbounded_String;
      CRLF    : constant String := ASCII.CR & ASCII.LF;
      use Ada.Strings.Unbounded;
   begin
      Channel := GNAT.Sockets.Stream (Conn);
      String'Write (Channel, Cmd & CRLF);
      loop
         GNAT.Sockets.Receive_Socket (Conn, Data, Size);
         for I in 1 .. Size loop
            Ret := Ret & Character'Val (Data (I));
         end loop;
         if Size < Data'Length then
            exit;
         end if;
      end loop;
      return UBS.To_String (Ret);
   end Redis_Call;

begin

   -- Open a socket connection
   Address.Addr := GNAT.Sockets.Addresses (Host_Entry, 1);
   Address.Port := Port_Number;
   GNAT.Sockets.Create_Socket (Socket);
   GNAT.Sockets.Connect_Socket (Socket, Address);

   -- send call to redis server and read result
   TIO.Put_Line(Redis_Call(Socket, "PING"));

   GNAT.Sockets.Close_Socket (Socket);
end Redis_Client;