Feat/add stdio transport (#25)

* feat: Add stdio transport method.
Update relevant documentation and code to support both SSE and stdio connection methods, initialize the EXCEL_FILES_PATH variable and perform the corresponding path handling.

* Remove PyPI mirror configuration.

src/excel_mcp/__main__.py

@@ -1,13 +1,19 @@
 import asyncio
-from .server import run_server
+import typer
+from typing import Optional
 
-def main():
-    """Start the Excel MCP server."""
+from .server import run_sse, run_stdio
+
+app = typer.Typer(help="Excel MCP Server")
+
+@app.command()
+def sse():
+    """Start Excel MCP Server in SSE mode"""
+    print("Excel MCP Server - SSE mode")
+    print("----------------------")
+    print("Press Ctrl+C to exit")
     try:
-        print("Excel MCP Server")
-        print("---------------")
-        print("Starting server... Press Ctrl+C to exit")
-        asyncio.run(run_server())
+        asyncio.run(run_sse())
     except KeyboardInterrupt:
         print("\nShutting down server...")
     except Exception as e:
@@ -15,7 +21,21 @@ def main():
         import traceback
         traceback.print_exc()
     finally:
-        print("Server stopped.")
+        print("Service stopped.")
+
+@app.command()
+def stdio():
+    """Start Excel MCP Server in stdio mode"""
+    try:
+        run_stdio()
+    except KeyboardInterrupt:
+        print("\nShutting down server...")
+    except Exception as e:
+        print(f"\nError: {e}")
+        import traceback
+        traceback.print_exc()
+    finally:
+        print("Service stopped.")
 
 if __name__ == "__main__":
-    main() 
+    app() 

src/excel_mcp/server.py

@@ -34,25 +34,31 @@ from excel_mcp.sheet import (
     unmerge_range,
 )
 
+# Get project root directory path for log file path.
+# When using the stdio transmission method,
+# relative paths may cause log files to fail to create
+# due to the client's running location and permission issues,
+# resulting in the program not being able to run.
+# Thus using os.path.join(ROOT_DIR, "excel-mcp.log") instead.
+
+ROOT_DIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+LOG_FILE = os.path.join(ROOT_DIR, "excel-mcp.log")
+
+
+# Initialize EXCEL_FILES_PATH variable without assigning a value
+EXCEL_FILES_PATH = None
+
 # Configure logging
 logging.basicConfig(
     level=logging.INFO,
     format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
     handlers=[
-        logging.StreamHandler(sys.stdout),
-        logging.FileHandler("excel-mcp.log")
+        # Referring to https://github.com/modelcontextprotocol/python-sdk/issues/409#issuecomment-2816831318
+        # The stdio mode server MUST NOT write anything to its stdout that is not a valid MCP message.
+        logging.FileHandler(LOG_FILE)
     ],
-    force=True
 )
-
 logger = logging.getLogger("excel-mcp")
-
-# Get Excel files path from environment or use default
-EXCEL_FILES_PATH = os.environ.get("EXCEL_FILES_PATH", "./excel_files")
-
-# Create the directory if it doesn't exist
-os.makedirs(EXCEL_FILES_PATH, exist_ok=True)
-
 # Initialize FastMCP server
 mcp = FastMCP(
     "excel-mcp",
@@ -80,8 +86,13 @@ def get_excel_path(filename: str) -> str:
     # If filename is already an absolute path, return it
     if os.path.isabs(filename):
         return filename
-        
-    # Use the configured Excel files path
+
+    # Check if in SSE mode (EXCEL_FILES_PATH is not None)
+    if EXCEL_FILES_PATH is None:
+        # Must use absolute path
+        raise ValueError(f"Invalid filename: {filename}, must be an absolute path when not in SSE mode")
+
+    # In SSE mode, if it's a relative path, resolve it based on EXCEL_FILES_PATH
     return os.path.join(EXCEL_FILES_PATH, filename)
 
 @mcp.tool()
@@ -491,10 +502,16 @@ def validate_excel_range(
         logger.error(f"Error validating range: {e}")
         raise
 
-async def run_server():
-    """Run the Excel MCP server."""
+async def run_sse():
+    """Run Excel MCP server in SSE mode."""
+    # Assign value to EXCEL_FILES_PATH in SSE mode
+    global EXCEL_FILES_PATH
+    EXCEL_FILES_PATH = os.environ.get("EXCEL_FILES_PATH", "./excel_files")
+    # Create directory if it doesn't exist
+    os.makedirs(EXCEL_FILES_PATH, exist_ok=True)
+    
     try:
-        logger.info(f"Starting Excel MCP server (files directory: {EXCEL_FILES_PATH})")
+        logger.info(f"Starting Excel MCP server with SSE transport (files directory: {EXCEL_FILES_PATH})")
         await mcp.run_sse_async()
     except KeyboardInterrupt:
         logger.info("Server stopped by user")
@@ -503,4 +520,19 @@ async def run_server():
         logger.error(f"Server failed: {e}")
         raise
     finally:
-        logger.info("Server shutdown complete") 
+        logger.info("Server shutdown complete")
+
+def run_stdio():
+    """Run Excel MCP server in stdio mode."""
+    # No need to assign EXCEL_FILES_PATH in stdio mode
+    
+    try:
+        logger.info("Starting Excel MCP server with stdio transport")
+        mcp.run(transport="stdio")
+    except KeyboardInterrupt:
+        logger.info("Server stopped by user")
+    except Exception as e:
+        logger.error(f"Server failed: {e}")
+        raise
+    finally:
+        logger.info("Server shutdown complete")