reslove conflict

source/lambda/chat_history/chat_history_management.py

@@ -0,0 +1,300 @@
+"""
+Lambda function for managing chat history operations.
+Provides REST API endpoints for listing sessions, messages,
+and managing message ratings.
+"""
+
+import json
+import logging
+import os
+from dataclasses import dataclass
+from datetime import datetime
+from decimal import Decimal
+from typing import Any, Dict, Optional
+
+import boto3
+from boto3.dynamodb.conditions import Key
+from botocore.paginate import TokenEncoder
+
+# Configure logging
+logger = logging.getLogger()
+logger.setLevel(logging.INFO)
+
+
+@dataclass
+class AwsResources:
+    """Centralized AWS resource management"""
+
+    dynamodb = boto3.resource("dynamodb")
+    dynamodb_client = boto3.client("dynamodb")
+
+    def __post_init__(self):
+        # Initialize DynamoDB tables
+        self.sessions_table = self.dynamodb.Table(Config.SESSIONS_TABLE_NAME)
+        self.messages_table = self.dynamodb.Table(Config.MESSAGES_TABLE_NAME)
+
+
+class Config:
+    """Configuration constants"""
+
+    SESSIONS_TABLE_NAME = os.environ["SESSIONS_TABLE_NAME"]
+    MESSAGES_TABLE_NAME = os.environ["MESSAGES_TABLE_NAME"]
+    SESSIONS_BY_TIMESTAMP_INDEX = os.environ["SESSIONS_BY_TIMESTAMP_INDEX_NAME"]
+    MESSAGES_BY_SESSION_ID_INDEX = os.environ["MESSAGES_BY_SESSION_ID_INDEX_NAME"]
+    DEFAULT_PAGE_SIZE = 50
+    DEFAULT_MAX_ITEMS = 50
+
+    CORS_HEADERS = {
+        "Content-Type": "application/json",
+        "Access-Control-Allow-Headers": "Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token",
+        "Access-Control-Allow-Origin": "*",
+        "Access-Control-Allow-Methods": "*",
+    }
+
+
+# Initialize AWS resources
+aws_resources = AwsResources()
+token_encoder = TokenEncoder()
+
+
+class DecimalEncoder(json.JSONEncoder):
+    """Custom JSON encoder for Decimal types"""
+
+    def default(self, o):
+        if isinstance(o, Decimal):
+            return str(o)
+        return super(DecimalEncoder, self).default(o)
+
+
+class PaginationConfig:
+    @staticmethod
+    def get_query_parameter(event: Dict[str, Any], parameter_name: str, default_value: Any = None) -> Any:
+        """Extract query parameter from event with default value"""
+        if event.get("queryStringParameters") and parameter_name in event["queryStringParameters"]:
+            return event["queryStringParameters"][parameter_name]
+        return default_value
+
+    @classmethod
+    def get_pagination_config(cls, event: Dict[str, Any]) -> Dict[str, Any]:
+        """Build pagination configuration from event parameters"""
+        return {
+            "MaxItems": int(cls.get_query_parameter(event, "max_items", Config.DEFAULT_MAX_ITEMS)),
+            "PageSize": int(cls.get_query_parameter(event, "page_size", Config.DEFAULT_PAGE_SIZE)),
+            "StartingToken": cls.get_query_parameter(event, "starting_token"),
+        }
+
+
+class ChatHistoryManager:
+    """Handles chat history related database operations"""
+
+    @staticmethod
+    def get_session(session_id: str, user_id: str) -> Optional[Dict]:
+        """Retrieve session details from DynamoDB"""
+        response = aws_resources.sessions_table.get_item(Key={"sessionId": session_id, "userId": user_id})
+        return response.get("Item")
+
+    @staticmethod
+    def get_message(message_id: str, session_id: str) -> Optional[Dict]:
+        """Retrieve message details from DynamoDB"""
+        response = aws_resources.messages_table.get_item(Key={"messageId": message_id, "sessionId": session_id})
+        return response.get("Item")
+
+    @staticmethod
+    def list_sessions(user_id: str, pagination_config: Dict[str, Any]) -> Dict[str, Any]:
+        """List sessions for a user with pagination"""
+        paginator = aws_resources.dynamodb_client.get_paginator("query")
+
+        response_iterator = paginator.paginate(
+            TableName=Config.SESSIONS_TABLE_NAME,
+            IndexName=Config.SESSIONS_BY_TIMESTAMP_INDEX,
+            KeyConditionExpression="userId = :user_id",
+            ExpressionAttributeValues={":user_id": {"S": user_id}},
+            ScanIndexForward=False,
+            PaginationConfig=pagination_config,
+        )
+
+        return ChatHistoryManager._process_paginated_response(
+            response_iterator,
+            ["sessionId", "userId", "createTimestamp", "latestQuestion"],
+            pagination_config=pagination_config,
+        )
+
+    @staticmethod
+    def list_messages(session_id: str, pagination_config: Dict[str, Any]) -> Dict[str, Any]:
+        """List messages for a session with pagination"""
+        paginator = aws_resources.dynamodb_client.get_paginator("query")
+
+        response_iterator = paginator.paginate(
+            TableName=Config.MESSAGES_TABLE_NAME,
+            IndexName=Config.MESSAGES_BY_SESSION_ID_INDEX,
+            KeyConditionExpression="sessionId = :session_id",
+            ExpressionAttributeValues={":session_id": {"S": session_id}},
+            ScanIndexForward=False,
+            PaginationConfig=pagination_config,
+        )
+
+        return ChatHistoryManager._process_paginated_response(
+            response_iterator,
+            ["messageId", "role", "content", "createTimestamp"],
+            pagination_config=pagination_config,
+            is_messages_list=True,
+        )
+
+    @staticmethod
+    def _process_paginated_response(
+        response_iterator, keys: list, pagination_config: Dict[str, Any] = None, is_messages_list: bool = False
+    ) -> Dict[str, Any]:
+        """Process paginated responses from DynamoDB"""
+        output = {}
+        processed_items = []
+
+        for page in response_iterator:
+            items = page["Items"]
+
+            for item in items:
+                processed_item = {key: item.get(key, {"S": ""})["S"] for key in keys}
+                # special handling for AI messages while listing messages
+                if is_messages_list and item.get("role", {}).get("S") == "ai":
+                    processed_item["additional_kwargs"] = json.loads(item["additional_kwargs"]["S"])
+                processed_items.append(processed_item)
+
+            if "LastEvaluatedKey" in page:
+                output["LastEvaluatedKey"] = token_encoder.encode({"ExclusiveStartKey": page["LastEvaluatedKey"]})
+            break
+
+        # Sort based on createTimestamp
+        # For sessions list: descending order (newest first)
+        # For messages list: ascending order (oldest first)
+        if "createTimestamp" in keys:
+            processed_items.sort(
+                key=lambda x: x["createTimestamp"],
+                reverse=not is_messages_list,  # False for messages (ascending), True for sessions (descending)
+            )
+
+        output["Items"] = processed_items
+        output["Config"] = pagination_config
+        output["Count"] = len(processed_items)
+        return output
+
+    @staticmethod
+    def add_feedback(
+        session_id: str, user_id: str, message_id: str, feedback_type: str, feedback_reason: str, suggest_message: Dict
+    ) -> Dict[str, Any]:
+        """Add feedback to a message"""
+        # First verify the session belongs to the user
+        session = ChatHistoryManager.get_session(session_id, user_id)
+        if not session:
+            return {"added": False, "error": "Session not found or unauthorized"}
+
+        message = ChatHistoryManager.get_message(message_id, session_id)
+        if not message:
+            return {"added": False, "error": "Message not found"}
+
+        try:
+            current_timestamp = datetime.utcnow().isoformat() + "Z"
+
+            # Update message with feedback
+            aws_resources.messages_table.update_item(
+                Key={"messageId": message_id, "sessionId": session_id},
+                UpdateExpression="SET feedbackType = :ft, feedbackReason = :fr, suggestMessage = :sm, lastModifiedTimestamp = :t",
+                ExpressionAttributeValues={
+                    ":ft": feedback_type,
+                    ":fr": feedback_reason,
+                    ":sm": suggest_message,
+                    ":t": current_timestamp,
+                },
+            )
+
+            # Update session last modified time
+            aws_resources.sessions_table.update_item(
+                Key={"sessionId": session_id, "userId": user_id},
+                UpdateExpression="SET lastModifiedTimestamp = :t",
+                ExpressionAttributeValues={":t": current_timestamp},
+            )
+
+            return {"added": True}
+        except Exception as e:
+            logger.error("Error adding feedback: %s", str(e))
+            return {"added": False, "error": str(e)}
+
+
+class ApiResponse:
+    """Standardized API response handler"""
+
+    @staticmethod
+    def success(data: Any, status_code: int = 200) -> Dict:
+        return {"statusCode": status_code, "headers": Config.CORS_HEADERS, "body": json.dumps(data, cls=DecimalEncoder)}
+
+    @staticmethod
+    def error(message: str, status_code: int = 500) -> Dict:
+        logger.error("Error: %s", message)
+        return {"statusCode": status_code, "headers": Config.CORS_HEADERS, "body": json.dumps({"error": str(message)})}
+
+
+class ApiHandler:
+    """API endpoint handlers"""
+
+    @staticmethod
+    def list_sessions(event: Dict) -> Dict:
+        """Handle GET /chat-history/sessions endpoint"""
+        try:
+            claims = json.loads(event["requestContext"]["authorizer"]["claims"])
+            user_id = claims["cognito:username"]
+            pagination_config = PaginationConfig.get_pagination_config(event)
+            result = ChatHistoryManager.list_sessions(user_id, pagination_config)
+            return ApiResponse.success(result)
+        except Exception as e:
+            return ApiResponse.error(str(e))
+
+    @staticmethod
+    def list_messages(event: Dict) -> Dict:
+        """Handle GET /chat-history/sessions/{sessionId}/messages endpoint"""
+        try:
+            session_id = event["pathParameters"]["sessionId"]
+            pagination_config = PaginationConfig.get_pagination_config(event)
+            result = ChatHistoryManager.list_messages(session_id, pagination_config)
+            return ApiResponse.success(result)
+        except Exception as e:
+            return ApiResponse.error(str(e))
+
+    @staticmethod
+    def add_feedback(event: Dict) -> Dict:
+        """Handle POST /sessions/{sessionId}/messages/{messageId}/feedback endpoint"""
+        try:
+            # Extract path parameters
+            session_id = event["pathParameters"]["sessionId"]
+            message_id = event["pathParameters"]["messageId"]
+            claims = json.loads(event["requestContext"]["authorizer"]["claims"])
+            user_id = claims["cognito:username"]
+
+            # Parse request body
+            body = json.loads(event["body"])
+            result = ChatHistoryManager.add_feedback(
+                session_id=session_id,
+                user_id=user_id,
+                message_id=message_id,
+                feedback_type=body["feedback_type"],
+                feedback_reason=body["feedback_reason"],
+                suggest_message=body["suggest_message"],
+            )
+            return ApiResponse.success(result)
+        except Exception as e:
+            return ApiResponse.error(str(e))
+
+
+def lambda_handler(event: Dict, context: Any) -> Dict:
+    """Routes API requests to appropriate handlers based on HTTP method and path"""
+    logger.info("Received event: %s", json.dumps(event))
+
+    routes = {
+        # More RESTful paths
+        ("GET", "/sessions"): ApiHandler.list_sessions,
+        ("GET", "/sessions/{sessionId}/messages"): ApiHandler.list_messages,
+        ("POST", "/sessions/{sessionId}/messages/{messageId}/feedback"): ApiHandler.add_feedback,
+    }
+
+    handler = routes.get((event["httpMethod"], event["resource"]))
+    if not handler:
+        return ApiResponse.error("Route not found", 404)
+
+    return handler(event)