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refactor(session): migrate to server-based session management and add tests (#9077)

Browse source 
* update MCP Tests

* [autofix.ci] apply automated fixes

* Update util.py

* [autofix.ci] apply automated fixes

* Refactor MCP session manager for better configurability and cleanup (#9176)

* Add log rotation and header validation features

Introduces support for log rotation via the LANGFLOW_LOG_ROTATION environment variable and CLI/config options, with documentation updates. Adds header validation and sanitization for MCP connections, ensuring RFC 7230 compliance and security. Frontend and backend now support passing custom headers for MCP servers. Includes extensive new and updated unit tests for header handling, MCP utilities, and log rotation.

* Add unit tests for MCP utilities and update disconnect logic

Added comprehensive unit tests for MCP utility functions, session management, header validation, and client classes in test_mcp_util.py. Updated MCPStdioClient and MCPSseClient disconnect methods for clearer session cleanup logic. Refactored test_mcp_component.py to remove redundant and duplicated tests, consolidating coverage in the new test suite.

* [autofix.ci] apply automated fixes

* Update test_mcp_memory_leak.py

* Update util.py

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Gabriel Luiz Freitas Almeida <gabriel@langflow.org>
This commit is contained in:
Edwin Jose 2025-08-09 05:30:39 -04:00 • committed by GitHub
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src/backend/tests/unit/base/mcp/__init__.py Normal file
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src/backend/tests/unit/base/mcp/test_mcp_util.py Normal file
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"""Unit tests for MCP utility functions.
This test suite validates the MCP utility functions including:
- Session management
- Header validation and processing
- Utility functions for name sanitization and schema conversion
"""
import shutil
from unittest.mock import AsyncMock, MagicMock, patch
import pytest
from langflow.base.mcp import util
from langflow.base.mcp.util import MCPSessionManager, MCPSseClient, MCPStdioClient, _process_headers, validate_headers
class TestMCPSessionManager:
@pytest.fixture
async def session_manager(self):
"""Create a session manager and clean it up after the test."""
manager = MCPSessionManager()
yield manager
# Clean up after test
await manager.cleanup_all()
async def test_session_caching(self, session_manager):
"""Test that sessions are properly cached and reused."""
context_id = "test_context"
connection_params = MagicMock()
transport_type = "stdio"
# Create a mock session that will appear healthy
mock_session = AsyncMock()
mock_session._write_stream = MagicMock()
mock_session._write_stream._closed = False
# Create a mock task that appears to be running
mock_task = AsyncMock()
mock_task.done = MagicMock(return_value=False)
with (
patch.object(session_manager, "_create_stdio_session") as mock_create,
patch.object(session_manager, "_validate_session_connectivity", return_value=True),
):
mock_create.return_value = (mock_session, mock_task)
# First call should create session
session1 = await session_manager.get_session(context_id, connection_params, transport_type)
# Second call should return cached session without creating new one
session2 = await session_manager.get_session(context_id, connection_params, transport_type)
assert session1 == session2
assert session1 == mock_session
# Should only create once since the second call should use the cached session
mock_create.assert_called_once()
async def test_session_cleanup(self, session_manager):
"""Test session cleanup functionality."""
context_id = "test_context"
server_key = "test_server"
session_id = "test_session"
# Add a session to the manager with proper mock setup using new structure
mock_task = AsyncMock()
mock_task.done = MagicMock(return_value=False) # Use MagicMock for sync method
mock_task.cancel = MagicMock() # Use MagicMock for sync method
# Set up the new session structure
session_manager.sessions_by_server[server_key] = {
"sessions": {session_id: {"session": AsyncMock(), "task": mock_task, "type": "stdio", "last_used": 0}},
"last_cleanup": 0,
}
# Set up mapping for backwards compatibility
session_manager._context_to_session[context_id] = (server_key, session_id)
await session_manager._cleanup_session(context_id)
# Should cancel the task and remove from sessions
mock_task.cancel.assert_called_once()
assert session_id not in session_manager.sessions_by_server[server_key]["sessions"]
async def test_server_switch_detection(self, session_manager):
"""Test that server switches are properly detected and handled."""
context_id = "test_context"
# First server
server1_params = MagicMock()
server1_params.command = "server1"
# Second server
server2_params = MagicMock()
server2_params.command = "server2"
with (
patch.object(session_manager, "_create_stdio_session") as mock_create,
patch.object(session_manager, "_validate_session_connectivity", return_value=True),
):
mock_session1 = AsyncMock()
mock_session2 = AsyncMock()
mock_task1 = AsyncMock()
mock_task2 = AsyncMock()
mock_create.side_effect = [(mock_session1, mock_task1), (mock_session2, mock_task2)]
# First connection
session1 = await session_manager.get_session(context_id, server1_params, "stdio")
# Switch to different server should create new session
session2 = await session_manager.get_session(context_id, server2_params, "stdio")
assert session1 != session2
assert mock_create.call_count == 2
class TestHeaderValidation:
"""Test the header validation functionality."""
def test_validate_headers_valid_input(self):
"""Test header validation with valid headers."""
headers = {"Authorization": "Bearer token123", "Content-Type": "application/json", "X-API-Key": "secret-key"}
result = validate_headers(headers)
# Headers should be normalized to lowercase
expected = {"authorization": "Bearer token123", "content-type": "application/json", "x-api-key": "secret-key"}
assert result == expected
def test_validate_headers_empty_input(self):
"""Test header validation with empty/None input."""
assert validate_headers({}) == {}
assert validate_headers(None) == {}
def test_validate_headers_invalid_names(self):
"""Test header validation with invalid header names."""
headers = {
"Invalid Header": "value", # spaces not allowed
"Header@Name": "value", # @ not allowed
"Header Name": "value", # spaces not allowed
"Valid-Header": "value", # this should pass
}
result = validate_headers(headers)
# Only the valid header should remain
assert result == {"valid-header": "value"}
def test_validate_headers_sanitize_values(self):
"""Test header value sanitization."""
headers = {
"Authorization": "Bearer \x00token\x1f with\r\ninjection",
"Clean-Header": " clean value ",
"Empty-After-Clean": "\x00\x01\x02",
"Tab-Header": "value\twith\ttabs", # tabs should be preserved
}
result = validate_headers(headers)
# Control characters should be removed, whitespace trimmed
# Header with injection attempts should be skipped
expected = {"clean-header": "clean value", "tab-header": "value\twith\ttabs"}
assert result == expected
def test_validate_headers_non_string_values(self):
"""Test header validation with non-string values."""
headers = {"String-Header": "valid", "Number-Header": 123, "None-Header": None, "List-Header": ["value"]}
result = validate_headers(headers)
# Only string headers should remain
assert result == {"string-header": "valid"}
def test_validate_headers_injection_attempts(self):
"""Test header validation against injection attempts."""
headers = {
"Injection1": "value\r\nInjected-Header: malicious",
"Injection2": "value\nX-Evil: attack",
"Safe-Header": "safe-value",
}
result = validate_headers(headers)
# Injection attempts should be filtered out
assert result == {"safe-header": "safe-value"}
class TestSSEHeaderIntegration:
"""Integration test to verify headers are properly passed through the entire SSE flow."""
async def test_headers_processing(self):
"""Test that headers flow properly from server config through to SSE client connection."""
# Test the header processing function directly
headers_input = [
{"key": "Authorization", "value": "Bearer test-token"},
{"key": "X-API-Key", "value": "secret-key"},
]
expected_headers = {
"authorization": "Bearer test-token", # normalized to lowercase
"x-api-key": "secret-key",
}
# Test _process_headers function with validation
processed_headers = _process_headers(headers_input)
assert processed_headers == expected_headers
# Test different input formats
# Test dict input with validation
dict_headers = {"Authorization": "Bearer dict-token", "Invalid Header": "bad"}
result = _process_headers(dict_headers)
# Invalid header should be filtered out, valid header normalized
assert result == {"authorization": "Bearer dict-token"}
# Test None input
assert _process_headers(None) == {}
# Test empty list
assert _process_headers([]) == {}
# Test malformed list
malformed_headers = [{"key": "Auth"}, {"value": "token"}] # Missing value/key
assert _process_headers(malformed_headers) == {}
# Test list with invalid header names
invalid_headers = [
{"key": "Valid-Header", "value": "good"},
{"key": "Invalid Header", "value": "bad"}, # spaces not allowed
]
result = _process_headers(invalid_headers)
assert result == {"valid-header": "good"}
async def test_sse_client_header_storage(self):
"""Test that SSE client properly stores headers in connection params."""
sse_client = MCPSseClient()
test_url = "http://test.url"
test_headers = {"Authorization": "Bearer test123", "Custom": "value"}
# Test that headers are properly stored in connection params
# Set connection params as a dict like the implementation expects
sse_client._connection_params = {
"url": test_url,
"headers": test_headers,
"timeout_seconds": 30,
"sse_read_timeout_seconds": 30,
}
# Verify headers are stored
assert sse_client._connection_params["url"] == test_url
assert sse_client._connection_params["headers"] == test_headers
class TestMCPUtilityFunctions:
"""Test utility functions from util.py that don't have dedicated test classes."""
def test_sanitize_mcp_name(self):
"""Test MCP name sanitization."""
assert util.sanitize_mcp_name("Test Name 123") == "test_name_123"
assert util.sanitize_mcp_name(" ") == ""
assert util.sanitize_mcp_name("123abc") == "_123abc"
assert util.sanitize_mcp_name("Tést-😀-Námé") == "test_name"
assert util.sanitize_mcp_name("a" * 100) == "a" * 46
def test_get_unique_name(self):
"""Test unique name generation."""
names = {"foo", "foo_1"}
assert util.get_unique_name("foo", 10, names) == "foo_2"
assert util.get_unique_name("bar", 10, names) == "bar"
assert util.get_unique_name("longname", 4, {"long"}) == "lo_1"
def test_is_valid_key_value_item(self):
"""Test key-value item validation."""
assert util._is_valid_key_value_item({"key": "a", "value": "b"}) is True
assert util._is_valid_key_value_item({"key": "a"}) is False
assert util._is_valid_key_value_item(["key", "value"]) is False
assert util._is_valid_key_value_item(None) is False
def test_validate_node_installation(self):
"""Test Node.js installation validation."""
if shutil.which("node"):
assert util._validate_node_installation("npx something") == "npx something"
else:
with pytest.raises(ValueError, match="Node.js is not installed"):
util._validate_node_installation("npx something")
assert util._validate_node_installation("echo test") == "echo test"
def test_create_input_schema_from_json_schema(self):
"""Test JSON schema to Pydantic model conversion."""
schema = {
"type": "object",
"properties": {
"foo": {"type": "string", "description": "desc"},
"bar": {"type": "integer"},
},
"required": ["foo"],
}
model_class = util.create_input_schema_from_json_schema(schema)
instance = model_class(foo="abc", bar=1)
assert instance.foo == "abc"
assert instance.bar == 1
with pytest.raises(Exception): # noqa: B017, PT011
model_class(bar=1) # missing required field
@pytest.mark.asyncio
async def test_validate_connection_params(self):
"""Test connection parameter validation."""
# Valid parameters
await util._validate_connection_params("Stdio", command="echo test")
await util._validate_connection_params("SSE", url="http://test")
# Invalid parameters
with pytest.raises(ValueError, match="Command is required for Stdio mode"):
await util._validate_connection_params("Stdio", command=None)
with pytest.raises(ValueError, match="URL is required for SSE mode"):
await util._validate_connection_params("SSE", url=None)
with pytest.raises(ValueError, match="Invalid mode"):
await util._validate_connection_params("InvalidMode")
@pytest.mark.asyncio
async def test_get_flow_snake_case_mocked(self):
"""Test flow lookup by snake case name with mocked session."""
class DummyFlow:
def __init__(self, name: str, user_id: str, *, is_component: bool = False, action_name: str | None = None):
self.name = name
self.user_id = user_id
self.is_component = is_component
self.action_name = action_name
class DummyExec:
def __init__(self, flows: list[DummyFlow]):
self._flows = flows
def all(self):
return self._flows
class DummySession:
def __init__(self, flows: list[DummyFlow]):
self._flows = flows
async def exec(self, stmt): # noqa: ARG002
return DummyExec(self._flows)
user_id = "123e4567-e89b-12d3-a456-426614174000"
flows = [DummyFlow("Test Flow", user_id), DummyFlow("Other", user_id)]
# Should match sanitized name
result = await util.get_flow_snake_case(util.sanitize_mcp_name("Test Flow"), user_id, DummySession(flows))
assert result is flows[0]
# Should return None if not found
result = await util.get_flow_snake_case("notfound", user_id, DummySession(flows))
assert result is None
class TestMCPStdioClientWithEverythingServer:
"""Test MCPStdioClient with the Everything MCP server."""
@pytest.fixture
def stdio_client(self):
"""Create a stdio client for testing."""
return MCPStdioClient()
@pytest.mark.asyncio
@pytest.mark.skipif(not shutil.which("npx"), reason="Node.js not available")
async def test_connect_to_everything_server(self, stdio_client):
"""Test connecting to the Everything MCP server."""
command = "npx -y @modelcontextprotocol/server-everything"
try:
# Connect to the server
tools = await stdio_client.connect_to_server(command)
# Verify tools were returned
assert len(tools) > 0
# Find the echo tool
echo_tool = None
for tool in tools:
if hasattr(tool, "name") and tool.name == "echo":
echo_tool = tool
break
assert echo_tool is not None, "Echo tool not found in server tools"
assert echo_tool.description is not None
# Verify the echo tool has the expected input schema
assert hasattr(echo_tool, "inputSchema")
assert echo_tool.inputSchema is not None
finally:
# Clean up the connection
await stdio_client.disconnect()
@pytest.mark.asyncio
@pytest.mark.skipif(not shutil.which("npx"), reason="Node.js not available")
async def test_run_echo_tool(self, stdio_client):
"""Test running the echo tool from the Everything server."""
command = "npx -y @modelcontextprotocol/server-everything"
try:
# Connect to the server
tools = await stdio_client.connect_to_server(command)
# Find the echo tool
echo_tool = None
for tool in tools:
if hasattr(tool, "name") and tool.name == "echo":
echo_tool = tool
break
assert echo_tool is not None, "Echo tool not found"
# Run the echo tool
test_message = "Hello, MCP!"
result = await stdio_client.run_tool("echo", {"message": test_message})
# Verify the result
assert result is not None
assert hasattr(result, "content")
assert len(result.content) > 0
# Check that the echo worked - content should contain our message
content_text = str(result.content[0])
assert test_message in content_text or "Echo:" in content_text
finally:
await stdio_client.disconnect()
@pytest.mark.asyncio
@pytest.mark.skipif(not shutil.which("npx"), reason="Node.js not available")
async def test_list_all_tools(self, stdio_client):
"""Test listing all available tools from the Everything server."""
command = "npx -y @modelcontextprotocol/server-everything"
try:
# Connect to the server
tools = await stdio_client.connect_to_server(command)
# Verify we have multiple tools
assert len(tools) >= 3 # Everything server typically has several tools
# Check that tools have the expected attributes
for tool in tools:
assert hasattr(tool, "name")
assert hasattr(tool, "description")
assert hasattr(tool, "inputSchema")
assert tool.name is not None
assert len(tool.name) > 0
# Common tools that should be available
expected_tools = ["echo"] # Echo is typically available
for expected_tool in expected_tools:
assert any(tool.name == expected_tool for tool in tools), f"Expected tool '{expected_tool}' not found"
finally:
await stdio_client.disconnect()
@pytest.mark.asyncio
@pytest.mark.skipif(not shutil.which("npx"), reason="Node.js not available")
async def test_session_reuse(self, stdio_client):
"""Test that sessions are properly reused."""
command = "npx -y @modelcontextprotocol/server-everything"
try:
# Set session context
stdio_client.set_session_context("test_session_reuse")
# Connect to the server
tools1 = await stdio_client.connect_to_server(command)
# Connect again - should reuse the session
tools2 = await stdio_client.connect_to_server(command)
# Should have the same tools
assert len(tools1) == len(tools2)
# Run a tool to verify the session is working
result = await stdio_client.run_tool("echo", {"message": "Session reuse test"})
assert result is not None
finally:
await stdio_client.disconnect()
class TestMCPSseClientWithDeepWikiServer:
"""Test MCPSseClient with the DeepWiki MCP server."""
@pytest.fixture
def sse_client(self):
"""Create an SSE client for testing."""
return MCPSseClient()
@pytest.mark.asyncio
async def test_connect_to_deepwiki_server(self, sse_client):
"""Test connecting to the DeepWiki MCP server."""
url = "https://mcp.deepwiki.com/sse"
try:
# Connect to the server
tools = await sse_client.connect_to_server(url)
# Verify tools were returned
assert len(tools) > 0
# Check for expected DeepWiki tools
expected_tools = ["read_wiki_structure", "read_wiki_contents", "ask_question"]
# Verify we have the expected tools
for expected_tool in expected_tools:
assert any(tool.name == expected_tool for tool in tools), f"Expected tool '{expected_tool}' not found"
except Exception as e:
# If the server is not accessible, skip the test
pytest.skip(f"DeepWiki server not accessible: {e}")
finally:
await sse_client.disconnect()
@pytest.mark.asyncio
async def test_run_wiki_structure_tool(self, sse_client):
"""Test running the read_wiki_structure tool."""
url = "https://mcp.deepwiki.com/sse"
try:
# Connect to the server
tools = await sse_client.connect_to_server(url)
# Find the read_wiki_structure tool
wiki_tool = None
for tool in tools:
if hasattr(tool, "name") and tool.name == "read_wiki_structure":
wiki_tool = tool
break
assert wiki_tool is not None, "read_wiki_structure tool not found"
# Run the tool with a test repository (use repoName as expected by the API)
result = await sse_client.run_tool("read_wiki_structure", {"repoName": "microsoft/vscode"})
# Verify the result
assert result is not None
assert hasattr(result, "content")
assert len(result.content) > 0
except Exception as e:
# If the server is not accessible or the tool fails, skip the test
pytest.skip(f"DeepWiki server test failed: {e}")
finally:
await sse_client.disconnect()
@pytest.mark.asyncio
async def test_ask_question_tool(self, sse_client):
"""Test running the ask_question tool."""
url = "https://mcp.deepwiki.com/sse"
try:
# Connect to the server
tools = await sse_client.connect_to_server(url)
# Find the ask_question tool
ask_tool = None
for tool in tools:
if hasattr(tool, "name") and tool.name == "ask_question":
ask_tool = tool
break
assert ask_tool is not None, "ask_question tool not found"
# Run the tool with a test question (use repoName as expected by the API)
result = await sse_client.run_tool(
"ask_question", {"repoName": "microsoft/vscode", "question": "What is VS Code?"}
)
# Verify the result
assert result is not None
assert hasattr(result, "content")
assert len(result.content) > 0
except Exception as e:
# If the server is not accessible or the tool fails, skip the test
pytest.skip(f"DeepWiki server test failed: {e}")
finally:
await sse_client.disconnect()
@pytest.mark.asyncio
async def test_url_validation(self, sse_client):
"""Test URL validation for SSE connections."""
# Test valid URL
valid_url = "https://mcp.deepwiki.com/sse"
is_valid, error = await sse_client.validate_url(valid_url)
assert is_valid or error == "" # Either valid or accessible
# Test invalid URL
invalid_url = "not_a_url"
is_valid, error = await sse_client.validate_url(invalid_url)
assert not is_valid
assert error != ""
@pytest.mark.asyncio
async def test_redirect_handling(self, sse_client):
"""Test redirect handling for SSE connections."""
# Test with the DeepWiki URL
url = "https://mcp.deepwiki.com/sse"
try:
# Check for redirects
final_url = await sse_client.pre_check_redirect(url)
# Should return a URL (either original or redirected)
assert final_url is not None
assert isinstance(final_url, str)
assert final_url.startswith("http")
except Exception as e:
# If the server is not accessible, skip the test
pytest.skip(f"DeepWiki server not accessible for redirect test: {e}")
@pytest.fixture
def mock_tool(self):
"""Create a mock MCP tool."""
tool = MagicMock()
tool.name = "test_tool"
tool.description = "Test tool description"
tool.inputSchema = {
"type": "object",
"properties": {"test_param": {"type": "string", "description": "Test parameter"}},
"required": ["test_param"],
}
return tool
@pytest.fixture
def mock_session(self, mock_tool):
"""Create a mock ClientSession."""
session = AsyncMock()
session.initialize = AsyncMock()
list_tools_result = MagicMock()
list_tools_result.tools = [mock_tool]
session.list_tools = AsyncMock(return_value=list_tools_result)
session.call_tool = AsyncMock(
return_value=MagicMock(content=[MagicMock(model_dump=lambda: {"result": "success"})])
)
return session
class TestMCPSseClientUnit:
"""Unit tests for MCPSseClient functionality."""
@pytest.fixture
def sse_client(self):
return MCPSseClient()
@pytest.mark.asyncio
async def test_client_initialization(self, sse_client):
"""Test that SSE client initializes correctly."""
# Client should initialize with default values
assert sse_client.session is None
assert sse_client._connection_params is None
assert sse_client._connected is False
assert sse_client._session_context is None
async def test_validate_url_valid(self, sse_client):
"""Test URL validation with valid URL."""
with patch("httpx.AsyncClient") as mock_client:
mock_response = MagicMock()
mock_response.status_code = 200
mock_client.return_value.__aenter__.return_value.get.return_value = mock_response
is_valid, error_msg = await sse_client.validate_url("http://test.url", {})
assert is_valid is True
assert error_msg == ""
async def test_validate_url_invalid_format(self, sse_client):
"""Test URL validation with invalid format."""
is_valid, error_msg = await sse_client.validate_url("invalid-url", {})
assert is_valid is False
assert "Invalid URL format" in error_msg
async def test_validate_url_with_404_response(self, sse_client):
"""Test URL validation with 404 response (should be valid for SSE)."""
with patch("httpx.AsyncClient") as mock_client:
mock_response = MagicMock()
mock_response.status_code = 404
mock_client.return_value.__aenter__.return_value.get.return_value = mock_response
is_valid, error_msg = await sse_client.validate_url("http://test.url", {})
assert is_valid is True
assert error_msg == ""
async def test_connect_to_server_with_headers(self, sse_client):
"""Test connecting to server via SSE with custom headers."""
test_url = "http://test.url"
test_headers = {"Authorization": "Bearer token123", "Custom-Header": "value"}
expected_headers = {"authorization": "Bearer token123", "custom-header": "value"} # normalized
with (
patch.object(sse_client, "validate_url", return_value=(True, "")),
patch.object(sse_client, "pre_check_redirect", return_value=test_url),
patch.object(sse_client, "_get_or_create_session") as mock_get_session,
):
# Mock session
mock_session = AsyncMock()
mock_tool = MagicMock()
mock_tool.name = "test_tool"
list_tools_result = MagicMock()
list_tools_result.tools = [mock_tool]
mock_session.list_tools = AsyncMock(return_value=list_tools_result)
mock_get_session.return_value = mock_session
tools = await sse_client.connect_to_server(test_url, test_headers)
assert len(tools) == 1
assert tools[0].name == "test_tool"
assert sse_client._connected is True
# Verify headers are stored in connection params (normalized)
assert sse_client._connection_params is not None
assert sse_client._connection_params["headers"] == expected_headers
assert sse_client._connection_params["url"] == test_url
async def test_headers_passed_to_session_manager(self, sse_client):
"""Test that headers are properly passed to the session manager."""
test_url = "http://test.url"
expected_headers = {"authorization": "Bearer token123", "x-api-key": "secret"} # normalized
sse_client._session_context = "test_context"
sse_client._connection_params = {
"url": test_url,
"headers": expected_headers, # Use normalized headers
"timeout_seconds": 30,
"sse_read_timeout_seconds": 30,
}
with patch.object(sse_client, "_get_session_manager") as mock_get_manager:
mock_manager = AsyncMock()
mock_session = AsyncMock()
mock_manager.get_session = AsyncMock(return_value=mock_session)
mock_get_manager.return_value = mock_manager
result_session = await sse_client._get_or_create_session()
# Verify session manager was called with correct parameters including normalized headers
mock_manager.get_session.assert_called_once_with("test_context", sse_client._connection_params, "sse")
assert result_session == mock_session
async def test_pre_check_redirect_with_headers(self, sse_client):
"""Test pre-check redirect functionality with custom headers."""
test_url = "http://test.url"
redirect_url = "http://redirect.url"
# Use pre-validated headers since pre_check_redirect expects already validated headers
test_headers = {"authorization": "Bearer token123"} # already normalized
with patch("httpx.AsyncClient") as mock_client:
mock_response = MagicMock()
mock_response.status_code = 307
mock_response.headers.get.return_value = redirect_url
mock_client.return_value.__aenter__.return_value.get.return_value = mock_response
result = await sse_client.pre_check_redirect(test_url, test_headers)
assert result == redirect_url
# Verify validated headers were passed to the request
mock_client.return_value.__aenter__.return_value.get.assert_called_with(
test_url, timeout=2.0, headers={"Accept": "text/event-stream", **test_headers}
)
async def test_run_tool_with_retry_on_connection_error(self, sse_client):
"""Test that run_tool retries on connection errors."""
# Setup connection state
sse_client._connected = True
sse_client._connection_params = {"url": "http://test.url", "headers": {}}
sse_client._session_context = "test_context"
call_count = 0
async def mock_get_session_side_effect():
nonlocal call_count
call_count += 1
session = AsyncMock()
if call_count == 1:
# First call fails with connection error
from anyio import ClosedResourceError
session.call_tool = AsyncMock(side_effect=ClosedResourceError())
else:
# Second call succeeds
mock_result = MagicMock()
session.call_tool = AsyncMock(return_value=mock_result)
return session
with (
patch.object(sse_client, "_get_or_create_session", side_effect=mock_get_session_side_effect),
patch.object(sse_client, "_get_session_manager") as mock_get_manager,
):
mock_manager = AsyncMock()
mock_get_manager.return_value = mock_manager
result = await sse_client.run_tool("test_tool", {"param": "value"})
# Should have retried and succeeded on second attempt
assert call_count == 2
assert result is not None
# Should have cleaned up the failed session
mock_manager._cleanup_session.assert_called_once_with("test_context")

627
src/backend/tests/unit/components/data/test_mcp_component.py
View file

@ -1,8 +1,15 @@
"""Unit tests for MCP component with actual MCP servers.
This test suite validates the MCP component functionality using real MCP servers:
- Everything server (stdio mode) - provides echo and other tools
- DeepWiki server (SSE mode) - provides wiki-related tools
"""
import shutil
from unittest.mock import AsyncMock, MagicMock, patch
import pytest
from langflow.base.mcp import util
from langflow.base.mcp.util import MCPSessionManager, MCPSseClient, MCPStdioClient, _process_headers, validate_headers
from langflow.base.mcp.util import MCPSessionManager, MCPSseClient, MCPStdioClient
from langflow.components.agents.mcp_component import MCPToolsComponent
from tests.base import ComponentTestBaseWithoutClient, VersionComponentMapping
@ -18,8 +25,11 @@ class TestMCPToolsComponent(ComponentTestBaseWithoutClient):
def default_kwargs(self):
"""Return the default kwargs for the component."""
return {
"mode": "Stdio",
"command": "npx -y @modelcontextprotocol/server-everything",
"sse_url": "https://mcp.deepwiki.com/sse",
"tool": "echo",
"mcp_server": {"name": "test_server", "config": {"command": "uvx mcp-server-fetch"}},
"tool": "",
}
@pytest.fixture
@ -27,34 +37,106 @@ class TestMCPToolsComponent(ComponentTestBaseWithoutClient):
"""Return the file names mapping for different versions."""
return []
@pytest.fixture
def mock_tool(self):
"""Create a mock MCP tool."""
tool = MagicMock()
tool.name = "test_tool"
tool.description = "Test tool description"
tool.inputSchema = {
"type": "object",
"properties": {"test_param": {"type": "string", "description": "Test parameter"}},
"required": ["test_param"],
}
return tool
@pytest.mark.asyncio
@pytest.mark.skipif(not shutil.which("npx"), reason="Node.js not available")
async def test_component_initialization(self, component_class, default_kwargs):
"""Test that the component initializes correctly."""
component = component_class(**default_kwargs)
# Check that the component has the expected attributes
assert hasattr(component, "stdio_client")
assert hasattr(component, "sse_client")
assert isinstance(component.stdio_client, MCPStdioClient)
assert isinstance(component.sse_client, MCPSseClient)
# Check that the component has a session manager
session_manager = component.stdio_client._get_session_manager()
assert isinstance(session_manager, MCPSessionManager)
class TestMCPToolsComponentIntegration:
"""Integration tests for the MCPToolsComponent."""
@pytest.fixture
def mock_session(self, mock_tool):
"""Create a mock ClientSession."""
session = AsyncMock()
session.initialize = AsyncMock()
list_tools_result = MagicMock()
list_tools_result.tools = [mock_tool]
session.list_tools = AsyncMock(return_value=list_tools_result)
session.call_tool = AsyncMock(
return_value=MagicMock(content=[MagicMock(model_dump=lambda: {"result": "success"})])
)
return session
def component(self):
"""Create a component for testing."""
return MCPToolsComponent()
@pytest.mark.asyncio
@pytest.mark.skipif(not shutil.which("npx"), reason="Node.js not available")
async def test_stdio_mode_integration(self, component):
"""Test the component in stdio mode with Everything server."""
# Configure for stdio mode
component.mode = "Stdio"
component.command = "npx -y @modelcontextprotocol/server-everything"
component.tool = "echo"
try:
# Mock the update_tool_list method to simulate server connection
tools, server_info = await component.update_tool_list()
# Should have tools
assert len(tools) > 0
# Should have server info
assert server_info is not None
assert isinstance(server_info, dict)
except Exception as e:
# If the server is not accessible, skip the test
pytest.skip(f"Everything server not accessible: {e}")
@pytest.mark.asyncio
async def test_sse_mode_integration(self, component):
"""Test the component in SSE mode with DeepWiki server."""
# Configure for SSE mode
component.mode = "SSE"
component.sse_url = "https://mcp.deepwiki.com/sse"
try:
# Mock the update_tool_list method to simulate server connection
tools, server_info = await component.update_tool_list()
# Should have tools
assert len(tools) > 0
# Should have server info
assert server_info is not None
assert isinstance(server_info, dict)
except Exception as e:
# If the server is not accessible, skip the test
pytest.skip(f"DeepWiki server not accessible: {e}")
@pytest.mark.asyncio
async def test_session_context_setting(self, component):
"""Test that session context is properly set."""
# Set session context
component.stdio_client.set_session_context("test_context")
component.sse_client.set_session_context("test_context")
# Verify context was set
assert component.stdio_client._session_context == "test_context"
assert component.sse_client._session_context == "test_context"
@pytest.mark.asyncio
async def test_session_manager_sharing(self, component):
"""Test that session managers are shared through component cache."""
# Get session managers
stdio_manager = component.stdio_client._get_session_manager()
sse_manager = component.sse_client._get_session_manager()
# Both should be MCPSessionManager instances
assert isinstance(stdio_manager, MCPSessionManager)
assert isinstance(sse_manager, MCPSessionManager)
# They should be the same instance (shared through cache)
assert stdio_manager is sse_manager
class TestMCPStdioClient:
class TestMCPComponentErrorHandling:
"""Test error handling in MCP components."""
@pytest.fixture
def stdio_client(self):
return MCPStdioClient()
@ -122,494 +204,3 @@ class TestMCPStdioClient:
mock_manager._cleanup_session.assert_called_once_with("test_context")
assert stdio_client.session is None
assert stdio_client._connected is False
class TestMCPSseClient:
@pytest.fixture
def sse_client(self):
return MCPSseClient()
async def test_validate_url_valid(self, sse_client):
"""Test URL validation with valid URL."""
with patch("httpx.AsyncClient") as mock_client:
mock_response = MagicMock()
mock_response.status_code = 200
mock_client.return_value.__aenter__.return_value.get.return_value = mock_response
is_valid, error_msg = await sse_client.validate_url("http://test.url", {})
assert is_valid is True
assert error_msg == ""
async def test_validate_url_invalid_format(self, sse_client):
"""Test URL validation with invalid format."""
is_valid, error_msg = await sse_client.validate_url("invalid-url", {})
assert is_valid is False
assert "Invalid URL format" in error_msg
async def test_validate_url_with_404_response(self, sse_client):
"""Test URL validation with 404 response (should be valid for SSE)."""
with patch("httpx.AsyncClient") as mock_client:
mock_response = MagicMock()
mock_response.status_code = 404
mock_client.return_value.__aenter__.return_value.get.return_value = mock_response
is_valid, error_msg = await sse_client.validate_url("http://test.url", {})
assert is_valid is True
assert error_msg == ""
async def test_connect_to_server_with_headers(self, sse_client):
"""Test connecting to server via SSE with custom headers."""
test_url = "http://test.url"
test_headers = {"Authorization": "Bearer token123", "Custom-Header": "value"}
expected_headers = {"authorization": "Bearer token123", "custom-header": "value"} # normalized
with (
patch.object(sse_client, "validate_url", return_value=(True, "")),
patch.object(sse_client, "pre_check_redirect", return_value=test_url),
patch.object(sse_client, "_get_or_create_session") as mock_get_session,
):
# Mock session
mock_session = AsyncMock()
mock_tool = MagicMock()
mock_tool.name = "test_tool"
list_tools_result = MagicMock()
list_tools_result.tools = [mock_tool]
mock_session.list_tools = AsyncMock(return_value=list_tools_result)
mock_get_session.return_value = mock_session
tools = await sse_client.connect_to_server(test_url, test_headers)
assert len(tools) == 1
assert tools[0].name == "test_tool"
assert sse_client._connected is True
# Verify headers are stored in connection params (normalized)
assert sse_client._connection_params is not None
assert sse_client._connection_params["headers"] == expected_headers
assert sse_client._connection_params["url"] == test_url
async def test_headers_passed_to_session_manager(self, sse_client):
"""Test that headers are properly passed to the session manager."""
test_url = "http://test.url"
expected_headers = {"authorization": "Bearer token123", "x-api-key": "secret"} # normalized
sse_client._session_context = "test_context"
sse_client._connection_params = {
"url": test_url,
"headers": expected_headers, # Use normalized headers
"timeout_seconds": 30,
"sse_read_timeout_seconds": 30,
}
with patch.object(sse_client, "_get_session_manager") as mock_get_manager:
mock_manager = AsyncMock()
mock_session = AsyncMock()
mock_manager.get_session = AsyncMock(return_value=mock_session)
mock_get_manager.return_value = mock_manager
result_session = await sse_client._get_or_create_session()
# Verify session manager was called with correct parameters including normalized headers
mock_manager.get_session.assert_called_once_with("test_context", sse_client._connection_params, "sse")
assert result_session == mock_session
async def test_pre_check_redirect_with_headers(self, sse_client):
"""Test pre-check redirect functionality with custom headers."""
test_url = "http://test.url"
redirect_url = "http://redirect.url"
# Use pre-validated headers since pre_check_redirect expects already validated headers
test_headers = {"authorization": "Bearer token123"} # already normalized
with patch("httpx.AsyncClient") as mock_client:
mock_response = MagicMock()
mock_response.status_code = 307
mock_response.headers.get.return_value = redirect_url
mock_client.return_value.__aenter__.return_value.get.return_value = mock_response
result = await sse_client.pre_check_redirect(test_url, test_headers)
assert result == redirect_url
# Verify validated headers were passed to the request
mock_client.return_value.__aenter__.return_value.get.assert_called_with(
test_url, timeout=2.0, headers={"Accept": "text/event-stream", **test_headers}
)
async def test_run_tool_with_retry_on_connection_error(self, sse_client):
"""Test that run_tool retries on connection errors."""
# Setup connection state
sse_client._connected = True
sse_client._connection_params = {"url": "http://test.url", "headers": {}}
sse_client._session_context = "test_context"
call_count = 0
async def mock_get_session_side_effect():
nonlocal call_count
call_count += 1
session = AsyncMock()
if call_count == 1:
# First call fails with connection error
from anyio import ClosedResourceError
session.call_tool = AsyncMock(side_effect=ClosedResourceError())
else:
# Second call succeeds
mock_result = MagicMock()
session.call_tool = AsyncMock(return_value=mock_result)
return session
with (
patch.object(sse_client, "_get_or_create_session", side_effect=mock_get_session_side_effect),
patch.object(sse_client, "_get_session_manager") as mock_get_manager,
):
mock_manager = AsyncMock()
mock_get_manager.return_value = mock_manager
result = await sse_client.run_tool("test_tool", {"param": "value"})
# Should have retried and succeeded on second attempt
assert call_count == 2
assert result is not None
# Should have cleaned up the failed session
mock_manager._cleanup_session.assert_called_once_with("test_context")
class TestMCPSessionManager:
@pytest.fixture
def session_manager(self):
return MCPSessionManager()
async def test_session_caching(self, session_manager):
"""Test that sessions are properly cached and reused."""
context_id = "test_context"
connection_params = MagicMock()
transport_type = "stdio"
# Create a mock session that will appear healthy
mock_session = AsyncMock()
mock_session._write_stream = MagicMock()
mock_session._write_stream._closed = False
# Create a mock task that appears to be running
mock_task = AsyncMock()
mock_task.done = MagicMock(return_value=False)
with (
patch.object(session_manager, "_create_stdio_session") as mock_create,
patch.object(session_manager, "_validate_session_connectivity", return_value=True),
):
mock_create.return_value = mock_session
# First call should create session
session1 = await session_manager.get_session(context_id, connection_params, transport_type)
# Manually populate the sessions cache as if the session was created properly
session_manager.sessions[context_id] = {"session": mock_session, "task": mock_task, "type": transport_type}
# Second call should return cached session without creating new one
session2 = await session_manager.get_session(context_id, connection_params, transport_type)
assert session1 == session2
assert session1 == mock_session
# Should only create once since the second call should use the cached session
mock_create.assert_called_once()
async def test_session_cleanup(self, session_manager):
"""Test session cleanup functionality."""
context_id = "test_context"
# Add a session to the manager with proper mock setup
mock_task = AsyncMock()
mock_task.done = MagicMock(return_value=False) # Use MagicMock for sync method
mock_task.cancel = MagicMock() # Use MagicMock for sync method
session_manager.sessions[context_id] = {"session": AsyncMock(), "task": mock_task, "type": "stdio"}
await session_manager._cleanup_session(context_id)
# Should cancel the task and remove from sessions
mock_task.cancel.assert_called_once()
assert context_id not in session_manager.sessions
async def test_server_switch_detection(self, session_manager):
"""Test that server switches are properly detected and handled."""
context_id = "test_context"
# First server
server1_params = MagicMock()
server1_params.command = "server1"
# Second server
server2_params = MagicMock()
server2_params.command = "server2"
with (
patch.object(session_manager, "_create_stdio_session") as mock_create,
patch.object(session_manager, "_validate_session_connectivity", return_value=True),
):
mock_session1 = AsyncMock()
mock_session2 = AsyncMock()
mock_create.side_effect = [mock_session1, mock_session2]
# First connection
session1 = await session_manager.get_session(context_id, server1_params, "stdio")
# Switch to different server should create new session
session2 = await session_manager.get_session(context_id, server2_params, "stdio")
assert session1 != session2
assert mock_create.call_count == 2
# Integration test for header functionality
class TestHeaderValidation:
"""Test the header validation functionality."""
def test_validate_headers_valid_input(self):
"""Test header validation with valid headers."""
headers = {"Authorization": "Bearer token123", "Content-Type": "application/json", "X-API-Key": "secret-key"}
result = validate_headers(headers)
# Headers should be normalized to lowercase
expected = {"authorization": "Bearer token123", "content-type": "application/json", "x-api-key": "secret-key"}
assert result == expected
def test_validate_headers_empty_input(self):
"""Test header validation with empty/None input."""
assert validate_headers({}) == {}
assert validate_headers(None) == {}
def test_validate_headers_invalid_names(self):
"""Test header validation with invalid header names."""
headers = {
"Invalid Header": "value", # spaces not allowed
"Header@Name": "value", # @ not allowed
"Header Name": "value", # spaces not allowed
"Valid-Header": "value", # this should pass
}
result = validate_headers(headers)
# Only the valid header should remain
assert result == {"valid-header": "value"}
def test_validate_headers_sanitize_values(self):
"""Test header value sanitization."""
headers = {
"Authorization": "Bearer \x00token\x1f with\r\ninjection",
"Clean-Header": " clean value ",
"Empty-After-Clean": "\x00\x01\x02",
"Tab-Header": "value\twith\ttabs", # tabs should be preserved
}
result = validate_headers(headers)
# Control characters should be removed, whitespace trimmed
# Header with injection attempts should be skipped
expected = {"clean-header": "clean value", "tab-header": "value\twith\ttabs"}
assert result == expected
def test_validate_headers_non_string_values(self):
"""Test header validation with non-string values."""
headers = {"String-Header": "valid", "Number-Header": 123, "None-Header": None, "List-Header": ["value"]}
result = validate_headers(headers)
# Only string headers should remain
assert result == {"string-header": "valid"}
def test_validate_headers_injection_attempts(self):
"""Test header validation against injection attempts."""
headers = {
"Injection1": "value\r\nInjected-Header: malicious",
"Injection2": "value\nX-Evil: attack",
"Safe-Header": "safe-value",
}
result = validate_headers(headers)
# Injection attempts should be filtered out
assert result == {"safe-header": "safe-value"}
class TestSSEHeaderIntegration:
"""Integration test to verify headers are properly passed through the entire SSE flow."""
async def test_headers_processing(self):
"""Test that headers flow properly from server config through to SSE client connection."""
# Test the header processing function directly
headers_input = [
{"key": "Authorization", "value": "Bearer test-token"},
{"key": "X-API-Key", "value": "secret-key"},
]
expected_headers = {
"authorization": "Bearer test-token", # normalized to lowercase
"x-api-key": "secret-key",
}
# Test _process_headers function with validation
processed_headers = _process_headers(headers_input)
assert processed_headers == expected_headers
# Test different input formats
# Test dict input with validation
dict_headers = {"Authorization": "Bearer dict-token", "Invalid Header": "bad"}
result = _process_headers(dict_headers)
# Invalid header should be filtered out, valid header normalized
assert result == {"authorization": "Bearer dict-token"}
# Test None input
assert _process_headers(None) == {}
# Test empty list
assert _process_headers([]) == {}
# Test malformed list
malformed_headers = [{"key": "Auth"}, {"value": "token"}] # Missing value/key
assert _process_headers(malformed_headers) == {}
# Test list with invalid header names
invalid_headers = [
{"key": "Valid-Header", "value": "good"},
{"key": "Invalid Header", "value": "bad"}, # spaces not allowed
]
result = _process_headers(invalid_headers)
assert result == {"valid-header": "good"}
async def test_sse_client_header_storage(self):
"""Test that SSE client properly stores headers in connection params."""
sse_client = MCPSseClient()
test_url = "http://test.url"
test_headers = {"Authorization": "Bearer test123", "Custom": "value"}
expected_headers = {"authorization": "Bearer test123", "custom": "value"} # normalized
with (
patch.object(sse_client, "validate_url", return_value=(True, "")),
patch.object(sse_client, "pre_check_redirect", return_value=test_url),
patch.object(sse_client, "_get_or_create_session") as mock_get_session,
):
mock_session = AsyncMock()
mock_tool = MagicMock()
mock_tool.name = "test_tool"
list_tools_result = MagicMock()
list_tools_result.tools = [mock_tool]
mock_session.list_tools = AsyncMock(return_value=list_tools_result)
mock_get_session.return_value = mock_session
await sse_client.connect_to_server(test_url, test_headers)
# Verify headers are stored correctly in connection params (normalized)
assert sse_client._connection_params is not None
assert sse_client._connection_params["headers"] == expected_headers
assert sse_client._connection_params["url"] == test_url
class TestMCPUtilityFunctions:
"""Test utility functions from util.py that don't have dedicated test classes."""
def test_sanitize_mcp_name(self):
"""Test MCP name sanitization."""
assert util.sanitize_mcp_name("Test Name 123") == "test_name_123"
assert util.sanitize_mcp_name(" ") == ""
assert util.sanitize_mcp_name("123abc") == "_123abc"
assert util.sanitize_mcp_name("Tést-😀-Námé") == "test_name"
assert util.sanitize_mcp_name("a" * 100) == "a" * 46
def test_get_unique_name(self):
"""Test unique name generation."""
names = {"foo", "foo_1"}
assert util.get_unique_name("foo", 10, names) == "foo_2"
assert util.get_unique_name("bar", 10, names) == "bar"
assert util.get_unique_name("longname", 4, {"long"}) == "lo_1"
def test_is_valid_key_value_item(self):
"""Test key-value item validation."""
assert util._is_valid_key_value_item({"key": "a", "value": "b"}) is True
assert util._is_valid_key_value_item({"key": "a"}) is False
assert util._is_valid_key_value_item(["key", "value"]) is False
assert util._is_valid_key_value_item(None) is False
def test_validate_node_installation(self):
"""Test Node.js installation validation."""
import shutil
if shutil.which("node"):
assert util._validate_node_installation("npx something") == "npx something"
else:
with pytest.raises(ValueError, match="Node.js is not installed"):
util._validate_node_installation("npx something")
assert util._validate_node_installation("echo test") == "echo test"
def test_create_input_schema_from_json_schema(self):
"""Test JSON schema to Pydantic model conversion."""
schema = {
"type": "object",
"properties": {
"foo": {"type": "string", "description": "desc"},
"bar": {"type": "integer"},
},
"required": ["foo"],
}
model_class = util.create_input_schema_from_json_schema(schema)
instance = model_class(foo="abc", bar=1)
assert instance.foo == "abc"
assert instance.bar == 1
with pytest.raises(Exception): # noqa: B017, PT011
model_class(bar=1) # missing required field
@pytest.mark.asyncio
async def test_validate_connection_params(self):
"""Test connection parameter validation."""
# Valid parameters
await util._validate_connection_params("Stdio", command="echo test")
await util._validate_connection_params("SSE", url="http://test")
# Invalid parameters
with pytest.raises(ValueError, match="Command is required for Stdio mode"):
await util._validate_connection_params("Stdio", command=None)
with pytest.raises(ValueError, match="URL is required for SSE mode"):
await util._validate_connection_params("SSE", url=None)
with pytest.raises(ValueError, match="Invalid mode"):
await util._validate_connection_params("InvalidMode")
@pytest.mark.asyncio
async def test_get_flow_snake_case_mocked(self):
"""Test flow lookup by snake case name with mocked session."""
class DummyFlow:
def __init__(self, name: str, user_id: str, *, is_component: bool = False, action_name: str | None = None):
self.name = name
self.user_id = user_id
self.is_component = is_component
self.action_name = action_name
class DummyExec:
def __init__(self, flows: list[DummyFlow]):
self._flows = flows
def all(self):
return self._flows
class DummySession:
def __init__(self, flows: list[DummyFlow]):
self._flows = flows
async def exec(self, stmt): # noqa: ARG002
return DummyExec(self._flows)
user_id = "123e4567-e89b-12d3-a456-426614174000"
flows = [DummyFlow("Test Flow", user_id), DummyFlow("Other", user_id)]
# Should match sanitized name
result = await util.get_flow_snake_case(util.sanitize_mcp_name("Test Flow"), user_id, DummySession(flows))
assert result is flows[0]
# Should return None if not found
result = await util.get_flow_snake_case("notfound", user_id, DummySession(flows))
assert result is None