Move uvicorn import to usage (#502)

pyproject.toml

@@ -29,7 +29,7 @@ dependencies = [
     "starlette>=0.27",
     "sse-starlette>=1.6.1",
     "pydantic-settings>=2.5.2",
-    "uvicorn>=0.23.1",
+    "uvicorn>=0.23.1; sys_platform != 'emscripten'",
 ]
 
 [project.optional-dependencies]

src/mcp/server/fastmcp/server.py

@@ -15,7 +15,6 @@ from typing import Any, Generic, Literal
 
 import anyio
 import pydantic_core
-import uvicorn
 from pydantic import BaseModel, Field
 from pydantic.networks import AnyUrl
 from pydantic_settings import BaseSettings, SettingsConfigDict
@@ -466,6 +465,7 @@ class FastMCP:
 
     async def run_sse_async(self) -> None:
         """Run the server using SSE transport."""
+        import uvicorn
         starlette_app = self.sse_app()
 
         config = uvicorn.Config(

uv.lock

@@ -496,7 +496,7 @@ dependencies = [
     { name = "pydantic-settings" },
     { name = "sse-starlette" },
     { name = "starlette" },
-    { name = "uvicorn" },
+    { name = "uvicorn", marker = "sys_platform != 'emscripten'" },
 ]
 
 [package.optional-dependencies]
@@ -540,7 +540,7 @@ requires-dist = [
     { name = "sse-starlette", specifier = ">=1.6.1" },
     { name = "starlette", specifier = ">=0.27" },
     { name = "typer", marker = "extra == 'cli'", specifier = ">=0.12.4" },
-    { name = "uvicorn", specifier = ">=0.23.1" },
+    { name = "uvicorn", marker = "sys_platform != 'emscripten'", specifier = ">=0.23.1" },
     { name = "websockets", marker = "extra == 'ws'", specifier = ">=15.0.1" },
 ]
 provides-extras = ["cli", "rich", "ws"]
@@ -1618,4 +1618,4 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/2b/fb/c492d6daa5ec067c2988ac80c61359ace5c4c674c532985ac5a123436cec/websockets-15.0.1-pp310-pypy310_pp73-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:b359ed09954d7c18bbc1680f380c7301f92c60bf924171629c5db97febb12f04", size = 174155 },
     { url = "https://files.pythonhosted.org/packages/68/a1/dcb68430b1d00b698ae7a7e0194433bce4f07ded185f0ee5fb21e2a2e91e/websockets-15.0.1-pp310-pypy310_pp73-win_amd64.whl", hash = "sha256:cad21560da69f4ce7658ca2cb83138fb4cf695a2ba3e475e0559e05991aa8122", size = 176884 },
     { url = "https://files.pythonhosted.org/packages/fa/a8/5b41e0da817d64113292ab1f8247140aac61cbf6cfd085d6a0fa77f4984f/websockets-15.0.1-py3-none-any.whl", hash = "sha256:f7a866fbc1e97b5c617ee4116daaa09b722101d4a3c170c787450ba409f9736f", size = 169743 },
-]
+]