feat(auth): implement auto guest mode and enhance token system

- Add role-based token system with metadata support
- Implement automatic guest mode for unconfigured authentication
- Create new /auth-status endpoint for authentication status checking
- Modify frontend to auto-detect auth status and bypass login when appropriate
- Add guest mode indicator in site header for better UX

This change allows users to automatically access the system without manual
login when authentication is not configured, while maintaining secure
authentication when credentials are properly set up.

lightrag/api/auth.py

@@ -6,8 +6,10 @@ from pydantic import BaseModel
 
 
 class TokenPayload(BaseModel):
-    sub: str
-    exp: datetime
+    sub: str  # Username
+    exp: datetime  # Expiration time
+    role: str = "user"  # User role, default is regular user
+    metadata: dict = {}  # Additional metadata
 
 
 class AuthHandler:
@@ -15,13 +17,55 @@ class AuthHandler:
         self.secret = os.getenv("TOKEN_SECRET", "4f85ds4f56dsf46")
         self.algorithm = "HS256"
         self.expire_hours = int(os.getenv("TOKEN_EXPIRE_HOURS", 4))
+        self.guest_expire_hours = int(os.getenv("GUEST_TOKEN_EXPIRE_HOURS", 2))  # Guest token default expiration time
 
-    def create_token(self, username: str) -> str:
-        expire = datetime.utcnow() + timedelta(hours=self.expire_hours)
-        payload = TokenPayload(sub=username, exp=expire)
+    def create_token(self, username: str, role: str = "user", custom_expire_hours: int = None, metadata: dict = None) -> str:
+        """
+        Create JWT token
+        
+        Args:
+            username: Username
+            role: User role, default is "user", guest is "guest"
+            custom_expire_hours: Custom expiration time (hours), if None use default value
+            metadata: Additional metadata
+            
+        Returns:
+            str: Encoded JWT token
+        """
+        # Choose default expiration time based on role
+        if custom_expire_hours is None:
+            if role == "guest":
+                expire_hours = self.guest_expire_hours
+            else:
+                expire_hours = self.expire_hours
+        else:
+            expire_hours = custom_expire_hours
+            
+        expire = datetime.utcnow() + timedelta(hours=expire_hours)
+        
+        # Create payload
+        payload = TokenPayload(
+            sub=username,
+            exp=expire,
+            role=role,
+            metadata=metadata or {}
+        )
+        
         return jwt.encode(payload.dict(), self.secret, algorithm=self.algorithm)
 
-    def validate_token(self, token: str) -> str:
+    def validate_token(self, token: str) -> dict:
+        """
+        Validate JWT token
+        
+        Args:
+            token: JWT token
+            
+        Returns:
+            dict: Dictionary containing user information
+            
+        Raises:
+            HTTPException: If token is invalid or expired
+        """
         try:
             payload = jwt.decode(token, self.secret, algorithms=[self.algorithm])
             expire_timestamp = payload["exp"]
@@ -31,7 +75,14 @@ class AuthHandler:
                 raise HTTPException(
                     status_code=status.HTTP_401_UNAUTHORIZED, detail="Token expired"
                 )
-            return payload["sub"]
+                
+            # Return complete payload instead of just username
+            return {
+                "username": payload["sub"],
+                "role": payload.get("role", "user"),
+                "metadata": payload.get("metadata", {}),
+                "exp": expire_time
+            }
         except jwt.PyJWTError:
             raise HTTPException(
                 status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token"