|
| 1 | +import multiprocessing |
| 2 | +import socket |
| 3 | +import time |
| 4 | +from typing import AsyncGenerator, Generator |
| 5 | + |
| 6 | +import anyio |
| 7 | +import pytest |
| 8 | +import uvicorn |
| 9 | +from pydantic import AnyUrl |
| 10 | +from starlette.applications import Starlette |
| 11 | +from starlette.requests import Request |
| 12 | +from starlette.routing import WebSocketRoute |
| 13 | + |
| 14 | +from mcp.client.session import ClientSession |
| 15 | +from mcp.client.websocket import websocket_client |
| 16 | +from mcp.server import Server |
| 17 | +from mcp.server.websocket import websocket_server |
| 18 | +from mcp.shared.exceptions import McpError |
| 19 | +from mcp.types import ( |
| 20 | + EmptyResult, |
| 21 | + ErrorData, |
| 22 | + InitializeResult, |
| 23 | + ReadResourceResult, |
| 24 | + TextContent, |
| 25 | + TextResourceContents, |
| 26 | + Tool, |
| 27 | +) |
| 28 | + |
| 29 | +SERVER_NAME = "test_server_for_WS" |
| 30 | + |
| 31 | + |
| 32 | +@pytest.fixture |
| 33 | +def server_port() -> int: |
| 34 | + with socket.socket() as s: |
| 35 | + s.bind(("127.0.0.1", 0)) |
| 36 | + return s.getsockname()[1] |
| 37 | + |
| 38 | + |
| 39 | +@pytest.fixture |
| 40 | +def server_url(server_port: int) -> str: |
| 41 | + return f"ws://127.0.0.1:{server_port}" |
| 42 | + |
| 43 | + |
| 44 | +# Test server implementation |
| 45 | +class ServerTest(Server): |
| 46 | + def __init__(self): |
| 47 | + super().__init__(SERVER_NAME) |
| 48 | + |
| 49 | + @self.read_resource() |
| 50 | + async def handle_read_resource(uri: AnyUrl) -> str | bytes: |
| 51 | + if uri.scheme == "foobar": |
| 52 | + return f"Read {uri.host}" |
| 53 | + elif uri.scheme == "slow": |
| 54 | + # Simulate a slow resource |
| 55 | + await anyio.sleep(2.0) |
| 56 | + return f"Slow response from {uri.host}" |
| 57 | + |
| 58 | + raise McpError( |
| 59 | + error=ErrorData( |
| 60 | + code=404, message="OOPS! no resource with that URI was found" |
| 61 | + ) |
| 62 | + ) |
| 63 | + |
| 64 | + @self.list_tools() |
| 65 | + async def handle_list_tools() -> list[Tool]: |
| 66 | + return [ |
| 67 | + Tool( |
| 68 | + name="test_tool", |
| 69 | + description="A test tool", |
| 70 | + inputSchema={"type": "object", "properties": {}}, |
| 71 | + ) |
| 72 | + ] |
| 73 | + |
| 74 | + @self.call_tool() |
| 75 | + async def handle_call_tool(name: str, args: dict) -> list[TextContent]: |
| 76 | + return [TextContent(type="text", text=f"Called {name}")] |
| 77 | + |
| 78 | + |
| 79 | +# Test fixtures |
| 80 | +def make_server_app() -> Starlette: |
| 81 | + """Create test Starlette app with WebSocket transport""" |
| 82 | + server = ServerTest() |
| 83 | + |
| 84 | + async def handle_ws(websocket): |
| 85 | + async with websocket_server( |
| 86 | + websocket.scope, websocket.receive, websocket.send |
| 87 | + ) as streams: |
| 88 | + await server.run( |
| 89 | + streams[0], streams[1], server.create_initialization_options() |
| 90 | + ) |
| 91 | + |
| 92 | + app = Starlette( |
| 93 | + routes=[ |
| 94 | + WebSocketRoute("/ws", endpoint=handle_ws), |
| 95 | + ] |
| 96 | + ) |
| 97 | + |
| 98 | + return app |
| 99 | + |
| 100 | + |
| 101 | +def run_server(server_port: int) -> None: |
| 102 | + app = make_server_app() |
| 103 | + server = uvicorn.Server( |
| 104 | + config=uvicorn.Config( |
| 105 | + app=app, host="127.0.0.1", port=server_port, log_level="error" |
| 106 | + ) |
| 107 | + ) |
| 108 | + print(f"starting server on {server_port}") |
| 109 | + server.run() |
| 110 | + |
| 111 | + # Give server time to start |
| 112 | + while not server.started: |
| 113 | + print("waiting for server to start") |
| 114 | + time.sleep(0.5) |
| 115 | + |
| 116 | + |
| 117 | +@pytest.fixture() |
| 118 | +def server(server_port: int) -> Generator[None, None, None]: |
| 119 | + proc = multiprocessing.Process( |
| 120 | + target=run_server, kwargs={"server_port": server_port}, daemon=True |
| 121 | + ) |
| 122 | + print("starting process") |
| 123 | + proc.start() |
| 124 | + |
| 125 | + # Wait for server to be running |
| 126 | + max_attempts = 20 |
| 127 | + attempt = 0 |
| 128 | + print("waiting for server to start") |
| 129 | + while attempt < max_attempts: |
| 130 | + try: |
| 131 | + with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s: |
| 132 | + s.connect(("127.0.0.1", server_port)) |
| 133 | + break |
| 134 | + except ConnectionRefusedError: |
| 135 | + time.sleep(0.1) |
| 136 | + attempt += 1 |
| 137 | + else: |
| 138 | + raise RuntimeError( |
| 139 | + "Server failed to start after {} attempts".format(max_attempts) |
| 140 | + ) |
| 141 | + |
| 142 | + yield |
| 143 | + |
| 144 | + print("killing server") |
| 145 | + # Signal the server to stop |
| 146 | + proc.kill() |
| 147 | + proc.join(timeout=2) |
| 148 | + if proc.is_alive(): |
| 149 | + print("server process failed to terminate") |
| 150 | + |
| 151 | + |
| 152 | +@pytest.fixture() |
| 153 | +async def initialized_ws_client_session( |
| 154 | + server, server_url: str |
| 155 | +) -> AsyncGenerator[ClientSession, None]: |
| 156 | + """Create and initialize a WebSocket client session""" |
| 157 | + async with websocket_client(server_url + "/ws") as streams: |
| 158 | + async with ClientSession(*streams) as session: |
| 159 | + # Test initialization |
| 160 | + result = await session.initialize() |
| 161 | + assert isinstance(result, InitializeResult) |
| 162 | + assert result.serverInfo.name == SERVER_NAME |
| 163 | + |
| 164 | + # Test ping |
| 165 | + ping_result = await session.send_ping() |
| 166 | + assert isinstance(ping_result, EmptyResult) |
| 167 | + |
| 168 | + yield session |
| 169 | + |
| 170 | + |
| 171 | +# Tests |
| 172 | +@pytest.mark.anyio |
| 173 | +async def test_ws_client_basic_connection(server: None, server_url: str) -> None: |
| 174 | + """Test the WebSocket connection establishment""" |
| 175 | + async with websocket_client(server_url + "/ws") as streams: |
| 176 | + async with ClientSession(*streams) as session: |
| 177 | + # Test initialization |
| 178 | + result = await session.initialize() |
| 179 | + assert isinstance(result, InitializeResult) |
| 180 | + assert result.serverInfo.name == SERVER_NAME |
| 181 | + |
| 182 | + # Test ping |
| 183 | + ping_result = await session.send_ping() |
| 184 | + assert isinstance(ping_result, EmptyResult) |
| 185 | + |
| 186 | + |
| 187 | +@pytest.mark.anyio |
| 188 | +async def test_ws_client_happy_request_and_response( |
| 189 | + initialized_ws_client_session: ClientSession, |
| 190 | +) -> None: |
| 191 | + """Test a successful request and response via WebSocket""" |
| 192 | + result = await initialized_ws_client_session.read_resource("foobar://example") |
| 193 | + assert isinstance(result, ReadResourceResult) |
| 194 | + assert isinstance(result.contents, list) |
| 195 | + assert len(result.contents) > 0 |
| 196 | + assert isinstance(result.contents[0], TextResourceContents) |
| 197 | + assert result.contents[0].text == "Read example" |
| 198 | + |
| 199 | + |
| 200 | +@pytest.mark.anyio |
| 201 | +async def test_ws_client_exception_handling( |
| 202 | + initialized_ws_client_session: ClientSession, |
| 203 | +) -> None: |
| 204 | + """Test exception handling in WebSocket communication""" |
| 205 | + with pytest.raises(McpError) as exc_info: |
| 206 | + await initialized_ws_client_session.read_resource("unknown://example") |
| 207 | + assert exc_info.value.error.code == 404 |
| 208 | + |
| 209 | + |
| 210 | +@pytest.mark.anyio |
| 211 | +async def test_ws_client_timeout( |
| 212 | + initialized_ws_client_session: ClientSession, |
| 213 | +) -> None: |
| 214 | + """Test timeout handling in WebSocket communication""" |
| 215 | + # Set a very short timeout to trigger a timeout exception |
| 216 | + with pytest.raises(TimeoutError): |
| 217 | + with anyio.fail_after(0.1): # 100ms timeout |
| 218 | + await initialized_ws_client_session.read_resource("slow://example") |
| 219 | + |
| 220 | + # Now test that we can still use the session after a timeout |
| 221 | + with anyio.fail_after(5): # Longer timeout to allow completion |
| 222 | + result = await initialized_ws_client_session.read_resource("foobar://example") |
| 223 | + assert isinstance(result, ReadResourceResult) |
| 224 | + assert isinstance(result.contents, list) |
| 225 | + assert len(result.contents) > 0 |
| 226 | + assert isinstance(result.contents[0], TextResourceContents) |
| 227 | + assert result.contents[0].text == "Read example" |
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