Integrate FastMCP

This commit integrates FastMCP, a high-level MCP server implementation originally written by Jeremiah Lowin,
into the official MCP SDK. It also updates dependencies and adds new dev dependencies.
It moves the existing SDK into a .lowlevel .

tests/server/fastmcp/resources/test_resource_template.py

@@ -0,0 +1,181 @@
+import json
+import pytest
+from pydantic import BaseModel
+
+from mcp.server.fastmcp.resources import FunctionResource, ResourceTemplate
+
+
+class TestResourceTemplate:
+    """Test ResourceTemplate functionality."""
+
+    def test_template_creation(self):
+        """Test creating a template from a function."""
+
+        def my_func(key: str, value: int) -> dict:
+            return {"key": key, "value": value}
+
+        template = ResourceTemplate.from_function(
+            fn=my_func,
+            uri_template="test://{key}/{value}",
+            name="test",
+        )
+        assert template.uri_template == "test://{key}/{value}"
+        assert template.name == "test"
+        assert template.mime_type == "text/plain"  # default
+        test_input = {"key": "test", "value": 42}
+        assert template.fn(**test_input) == my_func(**test_input)
+
+    def test_template_matches(self):
+        """Test matching URIs against a template."""
+
+        def my_func(key: str, value: int) -> dict:
+            return {"key": key, "value": value}
+
+        template = ResourceTemplate.from_function(
+            fn=my_func,
+            uri_template="test://{key}/{value}",
+            name="test",
+        )
+
+        # Valid match
+        params = template.matches("test://foo/123")
+        assert params == {"key": "foo", "value": "123"}
+
+        # No match
+        assert template.matches("test://foo") is None
+        assert template.matches("other://foo/123") is None
+
+    async def test_create_resource(self):
+        """Test creating a resource from a template."""
+
+        def my_func(key: str, value: int) -> dict:
+            return {"key": key, "value": value}
+
+        template = ResourceTemplate.from_function(
+            fn=my_func,
+            uri_template="test://{key}/{value}",
+            name="test",
+        )
+
+        resource = await template.create_resource(
+            "test://foo/123",
+            {"key": "foo", "value": 123},
+        )
+
+        assert isinstance(resource, FunctionResource)
+        content = await resource.read()
+        assert isinstance(content, str)
+        data = json.loads(content)
+        assert data == {"key": "foo", "value": 123}
+
+    async def test_template_error(self):
+        """Test error handling in template resource creation."""
+
+        def failing_func(x: str) -> str:
+            raise ValueError("Test error")
+
+        template = ResourceTemplate.from_function(
+            fn=failing_func,
+            uri_template="fail://{x}",
+            name="fail",
+        )
+
+        with pytest.raises(ValueError, match="Error creating resource from template"):
+            await template.create_resource("fail://test", {"x": "test"})
+
+    async def test_async_text_resource(self):
+        """Test creating a text resource from async function."""
+
+        async def greet(name: str) -> str:
+            return f"Hello, {name}!"
+
+        template = ResourceTemplate.from_function(
+            fn=greet,
+            uri_template="greet://{name}",
+            name="greeter",
+        )
+
+        resource = await template.create_resource(
+            "greet://world",
+            {"name": "world"},
+        )
+
+        assert isinstance(resource, FunctionResource)
+        content = await resource.read()
+        assert content == "Hello, world!"
+
+    async def test_async_binary_resource(self):
+        """Test creating a binary resource from async function."""
+
+        async def get_bytes(value: str) -> bytes:
+            return value.encode()
+
+        template = ResourceTemplate.from_function(
+            fn=get_bytes,
+            uri_template="bytes://{value}",
+            name="bytes",
+        )
+
+        resource = await template.create_resource(
+            "bytes://test",
+            {"value": "test"},
+        )
+
+        assert isinstance(resource, FunctionResource)
+        content = await resource.read()
+        assert content == b"test"
+
+    async def test_basemodel_conversion(self):
+        """Test handling of BaseModel types."""
+
+        class MyModel(BaseModel):
+            key: str
+            value: int
+
+        def get_data(key: str, value: int) -> MyModel:
+            return MyModel(key=key, value=value)
+
+        template = ResourceTemplate.from_function(
+            fn=get_data,
+            uri_template="test://{key}/{value}",
+            name="test",
+        )
+
+        resource = await template.create_resource(
+            "test://foo/123",
+            {"key": "foo", "value": 123},
+        )
+
+        assert isinstance(resource, FunctionResource)
+        content = await resource.read()
+        assert isinstance(content, str)
+        data = json.loads(content)
+        assert data == {"key": "foo", "value": 123}
+
+    async def test_custom_type_conversion(self):
+        """Test handling of custom types."""
+
+        class CustomData:
+            def __init__(self, value: str):
+                self.value = value
+
+            def __str__(self) -> str:
+                return self.value
+
+        def get_data(value: str) -> CustomData:
+            return CustomData(value)
+
+        template = ResourceTemplate.from_function(
+            fn=get_data,
+            uri_template="test://{value}",
+            name="test",
+        )
+
+        resource = await template.create_resource(
+            "test://hello",
+            {"value": "hello"},
+        )
+
+        assert isinstance(resource, FunctionResource)
+        content = await resource.read()
+        assert content == "hello"