"""
Blender MCP Server - Run with: blender --background --python blender_server.py
This server:
- Runs in Blender's background mode
- Handles connections in separate threads
- ALWAYS returns a response (success or error)
- Never blocks the main thread
- Provides progress reporting via send_status()
"""
import socket
import json
import traceback
import threading
import bpy
HOST = "127.0.0.1"
PORT = 8081
def handle_client(conn, addr):
"""Handle a single client connection with guaranteed response."""
print(f"[BlenderMCP] Client connected: {addr}")
try:
# Receive data (up to 1MB)
data = b""
conn.settimeout(5.0) # 5 second timeout for receiving
while True:
try:
chunk = conn.recv(4096)
if not chunk:
break
data += chunk
# Check if we have a complete JSON object
try:
json.loads(data.decode())
break # Valid JSON, stop receiving
except json.JSONDecodeError:
continue # Keep receiving
except socket.timeout:
break
if not data:
send_response(conn, {"status": "error", "error": "No data received"})
return
cmd = json.loads(data.decode())
script = cmd.get("script", "")
if not script:
send_response(conn, {"status": "error", "error": "No script provided"})
return
# Send initial status
send_response(conn, {"status": "running", "message": "Script execution started"})
# Create execution environment with send_status helper
def send_status(msg):
"""Send progress update to client."""
send_response(conn, {"status": "progress", "message": msg})
exec_env = {
"bpy": bpy,
"send_status": send_status,
"__builtins__": __builtins__,
}
# Execute the script
try:
exec(script, exec_env)
send_response(conn, {"status": "ok", "message": "Script completed successfully"})
except Exception as e:
send_response(conn, {
"status": "error",
"error": str(e),
"trace": traceback.format_exc()
})
except Exception as e:
try:
send_response(conn, {
"status": "error",
"error": f"Server error: {str(e)}",
"trace": traceback.format_exc()
})
except:
pass
finally:
try:
conn.close()
except:
pass
print(f"[BlenderMCP] Client disconnected: {addr}")
def send_response(conn, payload):
"""Send a JSON response to the client."""
try:
response = json.dumps(payload) + "\n"
conn.sendall(response.encode())
except Exception as e:
print(f"[BlenderMCP] Error sending response: {e}")
def main():
"""Main server loop."""
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind((HOST, PORT))
server.listen(5)
print("=" * 50)
print(f"[BlenderMCP] Server running on {HOST}:{PORT}")
print("[BlenderMCP] Waiting for connections...")
print("=" * 50)
try:
while True:
conn, addr = server.accept()
# Handle each client in a separate thread
thread = threading.Thread(target=handle_client, args=(conn, addr), daemon=True)
thread.start()
except KeyboardInterrupt:
print("\n[BlenderMCP] Server shutting down...")
finally:
server.close()
if __name__ == "__main__":
main()
