Files
mcp-python-sdk/tests/server/test_read_resource.py
David Soria Parra b1942b31c4 Fix #177: Returning multiple tool results (#222)
* feat: allow lowlevel servers to return a list of resources

The resource/read message in MCP allows of multiple resources
to be returned. However, in the SDK we do not allow this. This
change is such that we allow returning multiple resource in
the lowlevel API if needed. However in FastMCP we stick to
one, since a FastMCP resource defines the mime_type in the decorator
and hence a resource cannot dynamically return different mime_typed resources.
It also is just the better default to only return one resource.
However in the lowlevel API we will allow this.

Strictly speaking this is not a BC break since the new return value
is additive, but if people subclassed server, it will break them.

* feat: lower the type requriements for call_tool to Iterable
2025-02-20 21:31:26 +00:00

115 lines
3.4 KiB
Python

from collections.abc import Iterable
from pathlib import Path
from tempfile import NamedTemporaryFile
import pytest
from pydantic import AnyUrl, FileUrl
import mcp.types as types
from mcp.server.lowlevel.server import ReadResourceContents, Server
@pytest.fixture
def temp_file():
"""Create a temporary file for testing."""
with NamedTemporaryFile(mode="w", delete=False) as f:
f.write("test content")
path = Path(f.name).resolve()
yield path
try:
path.unlink()
except FileNotFoundError:
pass
@pytest.mark.anyio
async def test_read_resource_text(temp_file: Path):
server = Server("test")
@server.read_resource()
async def read_resource(uri: AnyUrl) -> Iterable[ReadResourceContents]:
return [ReadResourceContents(content="Hello World", mime_type="text/plain")]
# Get the handler directly from the server
handler = server.request_handlers[types.ReadResourceRequest]
# Create a request
request = types.ReadResourceRequest(
method="resources/read",
params=types.ReadResourceRequestParams(uri=FileUrl(temp_file.as_uri())),
)
# Call the handler
result = await handler(request)
assert isinstance(result.root, types.ReadResourceResult)
assert len(result.root.contents) == 1
content = result.root.contents[0]
assert isinstance(content, types.TextResourceContents)
assert content.text == "Hello World"
assert content.mimeType == "text/plain"
@pytest.mark.anyio
async def test_read_resource_binary(temp_file: Path):
server = Server("test")
@server.read_resource()
async def read_resource(uri: AnyUrl) -> Iterable[ReadResourceContents]:
return [
ReadResourceContents(
content=b"Hello World", mime_type="application/octet-stream"
)
]
# Get the handler directly from the server
handler = server.request_handlers[types.ReadResourceRequest]
# Create a request
request = types.ReadResourceRequest(
method="resources/read",
params=types.ReadResourceRequestParams(uri=FileUrl(temp_file.as_uri())),
)
# Call the handler
result = await handler(request)
assert isinstance(result.root, types.ReadResourceResult)
assert len(result.root.contents) == 1
content = result.root.contents[0]
assert isinstance(content, types.BlobResourceContents)
assert content.mimeType == "application/octet-stream"
@pytest.mark.anyio
async def test_read_resource_default_mime(temp_file: Path):
server = Server("test")
@server.read_resource()
async def read_resource(uri: AnyUrl) -> Iterable[ReadResourceContents]:
return [
ReadResourceContents(
content="Hello World",
# No mime_type specified, should default to text/plain
)
]
# Get the handler directly from the server
handler = server.request_handlers[types.ReadResourceRequest]
# Create a request
request = types.ReadResourceRequest(
method="resources/read",
params=types.ReadResourceRequestParams(uri=FileUrl(temp_file.as_uri())),
)
# Call the handler
result = await handler(request)
assert isinstance(result.root, types.ReadResourceResult)
assert len(result.root.contents) == 1
content = result.root.contents[0]
assert isinstance(content, types.TextResourceContents)
assert content.text == "Hello World"
assert content.mimeType == "text/plain"