Replace the telnet server by an RPC server

[dirkwhoffmann]

Current situation:

VirtualC64 includes a server that allows users to connect to RetroShell via Telnet. This implementation was primarily a proof of concept for the socket server code. From a practical standpoint, however, interacting with the emulator through Telnet offers little value.

Proposal:

Replace the Telnet server with an RPC server that exposes VirtualC64’s control interface via the JSON-RPC protocol. This change would make the system more flexible and could enable meaningful integrations in the future; for example, using VirtualC64 as a debugging backend in VSC.

[dirkwhoffmann]

Experimental RPC server support has been achieved.

Example 1:

• Start the RPC server in RetroShell:

  server rpc set PORT 8088
  server rpc start
  

• Send an RPC packet via netcat:

  echo '{"jsonrpc":"2.0","method":"retroshell","params":"shutdown","id":1}' | nc localhost 8088
  

  VirtualC64 executes the shutdown command in RetroShell and terminates the app.

Example 2:

• Start netcat

   nc localhost 8088
  

• Switch to the debugger and call the disassembler

  {"jsonrpc":"2.0","method":"retroshell","params":"debugger","id":1}
  {"jsonrpc":"2.0","method":"retroshell","params":"d $AF00","id":2}
  

  VirtualC64 responds with the package:

  {"jsonrpc":"2.0","method":"retroshell","params":"d $AF00","id":2}
  {"id":2,"jsonrpc":"2.0","result":"               AF00  00          BRK\n
               AF01  D1 7A       CMP (7A),Y\n
               AF03  D0 03       BNE AF08\n 
              AF05  4C 73 00    JMP 0073\n
               AF08  A2 0B       LDX #0B\n 
              AF0A  4C 37 A4    JMP A437\n
               AF0D  A0 15       LDY #15\n
               AF0F  68          PLA\n 
              AF10  68          PLA\n
               AF11  4C FA AD    JMP ADFA\n
               AF14  38          SEC\n
              AF15  A5 64       LDA 64\n
               AF17  E9 00       SBC #00\n
               AF19  A5 65       LDA 65\n
               AF1B  E9 A0       SBC #A0\n 
              AF1D  90 08       BCC AF27\n"}
  

Next step: Remove the telnet server

[dirkwhoffmann]

I decided to keep all existing servers and make them accessible through a dedicated settings panel. Previously, the servers had to be started via RetroShell.

The DAP server is not functional yet. I’m looking for a volunteer to develop a suitable DAP client to help move its implementation forward.