server: Parse port numbers from MCP server URLs in CORS proxy (#20208)

* Parse port numbers from MCP server URLs

* Pass scheme to http proxy for determining whether to use SSL

* Fix download on non-standard port and re-add port to logging

* add test

---------

Co-authored-by: Xuan Son Nguyen <son@huggingface.co>

tools/server/tests/unit/test_proxy.py

@@ -0,0 +1,41 @@
+import pytest
+from utils import *
+
+server = ServerPreset.tinyllama2()
+
+
+@pytest.fixture(autouse=True)
+def create_server():
+    global server
+    server = ServerPreset.tinyllama2()
+
+
+def test_mcp_no_proxy():
+    global server
+    server.webui_mcp_proxy = False
+    server.start()
+
+    res = server.make_request("GET", "/cors-proxy")
+    assert res.status_code == 404
+
+
+def test_mcp_proxy():
+    global server
+    server.webui_mcp_proxy = True
+    server.start()
+
+    url = f"http://{server.server_host}:{server.server_port}/cors-proxy?url=http://example.com"
+    res = requests.get(url)
+    assert res.status_code == 200
+    assert "Example Domain" in res.text
+
+
+def test_mcp_proxy_custom_port():
+    global server
+    server.webui_mcp_proxy = True
+    server.start()
+
+    # try getting the server's models API via the proxy
+    res = server.make_request("GET", f"/cors-proxy?url=http://{server.server_host}:{server.server_port}/models")
+    assert res.status_code == 200
+    assert "data" in res.body