166 lines
4.3 KiB
Python
166 lines
4.3 KiB
Python
#!/usr/bin/env python3
|
|
"""
|
|
MCP stdio-to-TCP bridge for BlueprintMCP.
|
|
|
|
Reads JSON-RPC messages from stdin, forwards them to the BlueprintMCP TCP server,
|
|
and writes responses to stdout. If the editor isn't running, returns valid MCP
|
|
error responses instead of crashing.
|
|
"""
|
|
|
|
import sys
|
|
import json
|
|
import socket
|
|
import time
|
|
|
|
HOST = "localhost"
|
|
PORT = 9847
|
|
CONNECT_TIMEOUT = 2
|
|
READ_TIMEOUT = 120
|
|
|
|
sock = None
|
|
|
|
|
|
def connect():
|
|
"""Try to connect to the editor. Returns True on success."""
|
|
global sock
|
|
if sock is not None:
|
|
return True
|
|
try:
|
|
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
|
|
s.settimeout(CONNECT_TIMEOUT)
|
|
s.connect((HOST, PORT))
|
|
s.settimeout(READ_TIMEOUT)
|
|
sock = s
|
|
return True
|
|
except (ConnectionRefusedError, socket.timeout, OSError):
|
|
return False
|
|
|
|
|
|
def disconnect():
|
|
global sock
|
|
if sock is not None:
|
|
try:
|
|
sock.close()
|
|
except Exception:
|
|
pass
|
|
sock = None
|
|
|
|
|
|
def send_and_receive(message):
|
|
"""Send a JSON-RPC message to the editor and return the response."""
|
|
data = json.dumps(message) + "\n"
|
|
sock.sendall(data.encode())
|
|
|
|
result = b""
|
|
while True:
|
|
chunk = sock.recv(65536)
|
|
if not chunk:
|
|
raise ConnectionError("Connection closed")
|
|
result += chunk
|
|
try:
|
|
return json.loads(result)
|
|
except json.JSONDecodeError:
|
|
continue
|
|
|
|
|
|
def editor_down_response(msg):
|
|
"""Return a valid MCP error response indicating the editor is down."""
|
|
msg_id = msg.get("id", 0)
|
|
method = msg.get("method", "")
|
|
|
|
if method == "initialize":
|
|
return {
|
|
"jsonrpc": "2.0",
|
|
"id": msg_id,
|
|
"result": {
|
|
"protocolVersion": "2024-11-05",
|
|
"capabilities": {"tools": {}},
|
|
"serverInfo": {"name": "blueprint-mcp", "version": "1.0.0"},
|
|
"_notice": "Unreal Editor is not running. No tools are available. Start the editor and restart Claude Code.",
|
|
},
|
|
}
|
|
|
|
if method == "notifications/initialized":
|
|
return None # No response needed for notifications
|
|
|
|
if method == "tools/list":
|
|
return {
|
|
"jsonrpc": "2.0",
|
|
"id": msg_id,
|
|
"result": {
|
|
"tools": [{
|
|
"name": "editor_not_running",
|
|
"description": "Unreal Editor is not running. Start the editor and restart Claude Code to get BlueprintMCP tools.",
|
|
"inputSchema": {"type": "object", "properties": {}},
|
|
}],
|
|
},
|
|
}
|
|
|
|
if method == "tools/call":
|
|
return {
|
|
"jsonrpc": "2.0",
|
|
"id": msg_id,
|
|
"result": {
|
|
"content": [
|
|
{"type": "text", "text": json.dumps({"error": "Unreal Editor is down."})}
|
|
],
|
|
"isError": True,
|
|
},
|
|
}
|
|
|
|
return {
|
|
"jsonrpc": "2.0",
|
|
"id": msg_id,
|
|
"error": {"code": -32000, "message": "Unreal Editor is down."},
|
|
}
|
|
|
|
|
|
def handle_message(msg):
|
|
"""Handle one JSON-RPC message. Try the editor first, fall back to offline responses."""
|
|
method = msg.get("method", "")
|
|
|
|
# Notifications don't get responses
|
|
if "id" not in msg:
|
|
if connect():
|
|
try:
|
|
sock.sendall((json.dumps(msg) + "\n").encode())
|
|
except Exception:
|
|
disconnect()
|
|
return None
|
|
|
|
# Try connecting (or reconnecting) to the editor
|
|
if not connect():
|
|
return editor_down_response(msg)
|
|
|
|
try:
|
|
return send_and_receive(msg)
|
|
except Exception:
|
|
disconnect()
|
|
# Retry once in case the connection was stale
|
|
if connect():
|
|
try:
|
|
return send_and_receive(msg)
|
|
except Exception:
|
|
disconnect()
|
|
return editor_down_response(msg)
|
|
|
|
|
|
def main():
|
|
for line in sys.stdin:
|
|
line = line.strip()
|
|
if not line:
|
|
continue
|
|
try:
|
|
msg = json.loads(line)
|
|
except json.JSONDecodeError:
|
|
continue
|
|
|
|
response = handle_message(msg)
|
|
if response is not None:
|
|
sys.stdout.write(json.dumps(response) + "\n")
|
|
sys.stdout.flush()
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|