feat: Enhance chat streaming and tool call processing (#498)

* feat: Enhance chat streaming and tool call processing

- Added support for MongoDB checkpointer in the chat streaming workflow.
- Introduced functions to process tool call chunks and sanitize arguments.
- Improved event message creation with additional metadata.
- Enhanced error handling for JSON serialization in event messages.
- Updated the frontend to convert escaped characters in tool call arguments.
- Refactored the workflow input preparation and initial message processing.
- Added new dependencies for MongoDB integration and tool argument sanitization.

* fix: Update MongoDB checkpointer configuration to use LANGGRAPH_CHECKPOINT_DB_URL

* feat: Add support for Postgres checkpointing and update README with database recommendations

* feat: Implement checkpoint saver functionality and update MongoDB connection handling

* refactor: Improve code formatting and readability in app.py and json_utils.py

* refactor: Clean up commented code and improve formatting in server.py

* refactor: Remove unused imports and improve code organization in app.py

* refactor: Improve code organization and remove unnecessary comments in app.py

* chore: use langgraph-checkpoint-postgres==2.0.21 to avoid the JSON convert issue in the latest version, implement chat stream persistant with Postgres

* feat: add MongoDB and PostgreSQL support for LangGraph checkpointing, enhance environment variable handling

* fix: update comments for clarity on Windows event loop policy

* chore: remove empty code changes in MongoDB and PostgreSQL checkpoint tests

* chore: clean up unused imports and code in checkpoint-related files

* chore: remove empty code changes in test_checkpoint.py

* chore: remove empty code changes in test_checkpoint.py

* chore: remove empty code changes in test_checkpoint.py

* test: update status code assertions in MCP endpoint tests to allow for 403 responses

* test: update MCP endpoint tests to assert specific status codes and enable MCP server configuration

* chore: remove unnecessary environment variables from unittest workflow

* fix: invert condition for MCP server configuration check to raise 403 when disabled

* chore: remove pymongo from test dependencies in uv.lock

* chore:  optimize the _get_agent_name method

* test: enhance ChatStreamManager tests for PostgreSQL and MongoDB initialization

* test: add persistence tests for ChatStreamManager with PostgreSQL and MongoDB

* test: add unit tests for ChatStreamManager initialization with PostgreSQL and MongoDB

* test: enhance persistence tests for ChatStreamManager with PostgreSQL and MongoDB to verify message aggregation

* test: add unit tests for ChatStreamManager with PostgreSQL and MongoDB

* test: add unit tests for ChatStreamManager initialization with PostgreSQL and MongoDB

* test: add unit tests for ChatStreamManager initialization with PostgreSQL and MongoDB

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

src/utils/json_utils.py

@@ -3,11 +3,33 @@
 
 import logging
 import json
+from typing import Any
 import json_repair
 
 logger = logging.getLogger(__name__)
 
 
+def sanitize_args(args: Any) -> str:
+    """
+    Sanitize tool call arguments to prevent special character issues.
+
+    Args:
+        args: Tool call arguments string
+
+    Returns:
+        str: Sanitized arguments string
+    """
+    if not isinstance(args, str):
+        return ""
+    else:
+        return (
+            args.replace("[", "[")
+            .replace("]", "]")
+            .replace("{", "{")
+            .replace("}", "}")
+        )
+
+
 def repair_json_output(content: str) -> str:
     """
     Repair and normalize JSON output.