feat: add patch_mimetype function for consistent mimetype handling

module/webui/patch.py

@@ -39,3 +39,24 @@ def patch_executor():
 
     loop = asyncio.get_event_loop()
     loop.set_default_executor(CachedThreadPoolExecutor.executor)
+
+
+def patch_mimetype():
+    """
+    Patch mimetype db to use the builtin table instead of reading from environment.
+
+    By default, mimetype reads user configured mimetype table from environment. It's good for server but bad on our
+    side, because we deploy on user's machine which may have polluted environment. To have a consistent behaviour on
+    all deployment, we use the builtin mimetype table only.
+    """
+    import mimetypes
+    # lock as inited
+    mimetypes.inited = True
+    # create a new clean instance
+    db = mimetypes.MimeTypes(filenames=())
+    mimetypes._db = db
+    # override global variable
+    mimetypes.encodings_map = db.encodings_map
+    mimetypes.suffix_map = db.suffix_map
+    mimetypes.types_map = db.types_map[True]
+    mimetypes.common_types = db.types_map[False]