[Misc] Normalize --host parameter to use plain hostname without scheme (#19309)

Co-authored-by: 墨楼 <huangzhilin.hzl@antgroup.com>
Co-authored-by: Liangsheng Yin <lsyincs@gmail.com>
Co-authored-by: Liangsheng Yin <hnyls2002@gmail.com>

python/sglang/utils.py

@@ -12,6 +12,7 @@ import sys
 import time
 import traceback
 import urllib.request
+import warnings
 import weakref
 from collections import OrderedDict
 from concurrent.futures import ThreadPoolExecutor
@@ -122,6 +123,19 @@ def dump_state_text(filename: str, states: list, mode: str = "w"):
             )
 
 
+def normalize_base_url(host: str, port: int) -> str:
+    if host.startswith("http://") or host.startswith("https://"):
+        warnings.warn(
+            f"Including the scheme in --host ('{host}') is deprecated. "
+            f"Pass just the hostname (e.g. '127.0.0.1') instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+    else:
+        host = f"http://{host}"
+    return f"{host}:{port}"
+
+
 class HttpResponse:
     def __init__(self, resp):
         self.resp = resp