Add authentication support for MCP servers

README.md

@@ -13,6 +13,7 @@ A zero-configuration tool for automatically exposing FastAPI endpoints as Model
 - **Preserving schemas** of your request models and response models
 - **Preserve documentation** of all your endpoints, just as it is in Swagger
 - **Extend** - Add custom MCP tools alongside the auto-generated ones
+- **Authentication** - Secure your MCP server with various authentication methods
 
 ## Installation
 
@@ -49,6 +50,71 @@ add_mcp_server(
 
 That's it! Your auto-generated MCP server is now available at `https://app.base.url/mcp`.
 
+## Authentication
+
+FastAPI-MCP supports various authentication methods to secure your MCP server:
+
+### Simple Bearer Token Authentication
+
+```python
+from fastapi import FastAPI
+from fastapi_mcp import add_mcp_server, AuthConfig
+
+app = FastAPI()
+
+# Configure authentication with a bearer token
+auth_config = AuthConfig(
+    enabled=True,
+    bearer_token="your-secret-token"  # This should be a secure token
+)
+
+# Add MCP server with authentication
+mcp_server = add_mcp_server(
+    app,
+    mount_path="/mcp",
+    name="Authenticated MCP API",
+    auth_config=auth_config
+)
+```
+
+### API Key Authentication
+
+```python
+from fastapi_mcp import AuthConfig
+
+# Configure authentication with an API key in header
+auth_config = AuthConfig(
+    enabled=True,
+    api_key="your-api-key",
+    api_key_name="X-API-Key",
+    api_key_in="header"  # Can be "header" or "query"
+)
+```
+
+### Custom Authentication
+
+For more complex authentication scenarios, you can use a custom authentication function:
+
+```python
+from fastapi import Request
+from fastapi_mcp import AuthConfig
+
+# Define your custom authentication function
+async def my_auth_function(request: Request) -> bool:
+    # Your authentication logic here
+    # Return True if authenticated, False otherwise
+    token = request.headers.get("Authorization", "").replace("Bearer ", "")
+    return token == "valid-token"
+
+# Configure authentication with a custom function
+auth_config = AuthConfig(
+    enabled=True,
+    custom_auth_func=my_auth_function
+)
+```
+
+See the [examples/authenticated_server.py](examples/authenticated_server.py) and [examples/simple_bearer_auth.py](examples/simple_bearer_auth.py) for complete working examples.
+
 ## Advanced Usage
 
 FastAPI-MCP provides several ways to customize and control how your MCP server is created and configured. Here are some advanced usage patterns:
@@ -160,4 +226,4 @@ MIT License. Copyright (c) 2024 Tadata Inc.
 
 ## About
 
-Developed and maintained by [Tadata Inc.](https://github.com/tadata-org)
+Developed and maintained by [Tadata Inc.](https://github.com/tadata-org)

examples/authenticated_server.py

@@ -0,0 +1,231 @@
+"""
+Example of a FastAPI-MCP server with authentication.
+
+This example demonstrates how to add authentication to an MCP server.
+"""
+
+from fastapi import FastAPI, Depends, HTTPException
+from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
+from pydantic import BaseModel
+from typing import List, Optional, Dict
+from datetime import datetime, timedelta
+import jwt
+from jwt.exceptions import PyJWTError
+
+from fastapi_mcp import add_mcp_server, AuthConfig
+
+# Create FastAPI app
+app = FastAPI(
+    title="Authenticated MCP Example",
+    description="An example of an MCP server with authentication",
+)
+
+# Secret key for JWT token
+SECRET_KEY = "a_very_secret_key_that_should_be_changed_in_production"
+ALGORITHM = "HS256"
+ACCESS_TOKEN_EXPIRE_MINUTES = 30
+
+# Fake users database
+fake_users_db = {
+    "johndoe": {
+        "username": "johndoe",
+        "full_name": "John Doe",
+        "email": "[email protected]",
+        "hashed_password": "fakehashedsecret",
+        "disabled": False,
+    },
+    "alice": {
+        "username": "alice",
+        "full_name": "Alice Wonderland",
+        "email": "[email protected]",
+        "hashed_password": "fakehashedsecret2",
+        "disabled": False,
+    },
+}
+
+# OAuth2 scheme
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")
+
+
+# Models
+class User(BaseModel):
+    username: str
+    email: Optional[str] = None
+    full_name: Optional[str] = None
+    disabled: Optional[bool] = None
+
+
+class UserInDB(User):
+    hashed_password: str
+
+
+class Token(BaseModel):
+    access_token: str
+    token_type: str
+
+
+class TokenData(BaseModel):
+    username: Optional[str] = None
+
+
+def verify_password(plain_password, hashed_password):
+    """Verify password."""
+    # This is a fake hash verification - in a real app, use proper hashing
+    return plain_password == "secret" and hashed_password == "fakehashedsecret"
+
+
+def get_user(db, username: str):
+    """Get user from the database."""
+    if username in db:
+        user_dict = db[username]
+        return UserInDB(**user_dict)
+
+
+def authenticate_user(fake_db, username: str, password: str):
+    """Authenticate a user."""
+    user = get_user(fake_db, username)
+    if not user:
+        return False
+    if not verify_password(password, user.hashed_password):
+        return False
+    return user
+
+
+def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
+    """Create a JWT token."""
+    to_encode = data.copy()
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(minutes=15)
+    to_encode.update({"exp": expire})
+    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
+    return encoded_jwt
+
+
+async def get_current_user(token: str = Depends(oauth2_scheme)):
+    """Get the current user from JWT token."""
+    credentials_exception = HTTPException(
+        status_code=401,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username: str = payload.get("sub")
+        if username is None:
+            raise credentials_exception
+        token_data = TokenData(username=username)
+    except PyJWTError:
+        raise credentials_exception
+    user = get_user(fake_users_db, username=token_data.username)
+    if user is None:
+        raise credentials_exception
+    return user
+
+
+async def get_current_active_user(current_user: User = Depends(get_current_user)):
+    """Get the current active user."""
+    if current_user.disabled:
+        raise HTTPException(status_code=400, detail="Inactive user")
+    return current_user
+
+
+@app.post("/token", response_model=Token)
+async def login_for_access_token(form_data: OAuth2PasswordRequestForm = Depends()):
+    """Login to get an access token."""
+    user = authenticate_user(fake_users_db, form_data.username, form_data.password)
+    if not user:
+        raise HTTPException(
+            status_code=401,
+            detail="Incorrect username or password",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+    access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
+    access_token = create_access_token(
+        data={"sub": user.username}, expires_delta=access_token_expires
+    )
+    return {"access_token": access_token, "token_type": "bearer"}
+
+
+@app.get("/users/me/", response_model=User)
+async def read_users_me(current_user: User = Depends(get_current_active_user)):
+    """Get current user information."""
+    return current_user
+
+
+# Sample items for a simple API
+items_db: Dict[str, dict] = {
+    "1": {"id": "1", "name": "Foo", "description": "This is foo"},
+    "2": {"id": "2", "name": "Bar", "description": "This is bar"},
+    "3": {"id": "3", "name": "Baz", "description": "This is baz"},
+}
+
+
+@app.get("/items/", response_model=List[dict])
+async def read_items(current_user: User = Depends(get_current_active_user)):
+    """Get all items, requires authentication."""
+    return list(items_db.values())
+
+
+@app.get("/items/{item_id}", response_model=dict)
+async def read_item(item_id: str, current_user: User = Depends(get_current_active_user)):
+    """Get a specific item, requires authentication."""
+    if item_id not in items_db:
+        raise HTTPException(status_code=404, detail="Item not found")
+    return items_db[item_id]
+
+
+# Function to verify JWT tokens for MCP authentication
+async def authenticate_mcp_request(request):
+    """Custom authentication function for MCP server."""
+    try:
+        # Get token from Authorization header
+        auth_header = request.headers.get("Authorization", "")
+        if not auth_header or not auth_header.startswith("Bearer "):
+            return False
+
+        token = auth_header.replace("Bearer ", "")
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username = payload.get("sub")
+
+        # Verify user exists in database
+        if not username or username not in fake_users_db:
+            return False
+
+        # Check if user is disabled
+        if fake_users_db[username].get("disabled", False):
+            return False
+
+        return True
+    except Exception:
+        return False
+
+
+# Add MCP server with authentication
+auth_config = AuthConfig(
+    enabled=True,
+    # Define a custom auth function that validates JWT tokens
+    custom_auth_func=authenticate_mcp_request
+)
+
+mcp_server = add_mcp_server(
+    app,
+    mount_path="/mcp",
+    name="Authenticated MCP API",
+    description="MCP server with JWT authentication",
+    base_url="http://localhost:8000",
+    auth_config=auth_config
+)
+
+
+# Add a custom MCP tool
+@mcp_server.tool()
+async def get_item_count() -> int:
+    """Get the total number of items in the database."""
+    return len(items_db)
+
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run(app, host="127.0.0.1", port=8000)