From 1e2c94a945a15b642e766bb82a1a17e7d36e6abc Mon Sep 17 00:00:00 2001
From: Huanyi Xie <74809554+xiehuanyi@users.noreply.github.com>
Date: Sun, 11 Oct 2026 15:16:55 +0300
Subject: [PATCH 1/2] Support slicing header sequences

---
 h11/_headers.py                          | 14 +++++++++++-
 h11/tests/test_headers.py                | 28 ++++++++++++++++++++++++
 newsfragments/headers-slicing.bugfix.rst |  1 +
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 newsfragments/headers-slicing.bugfix.rst

diff --git a/h11/_headers.py b/h11/_headers.py
index 31da3e2..d625ceb 100644
--- a/h11/_headers.py
+++ b/h11/_headers.py
@@ -116,7 +116,19 @@ def __len__(self) -> int:
     def __repr__(self) -> str:
         return "<Headers(%s)>" % repr(list(self))
 
-    def __getitem__(self, idx: int) -> Tuple[bytes, bytes]:  # type: ignore[override]
+    @overload
+    def __getitem__(self, idx: int) -> Tuple[bytes, bytes]:
+        ...
+
+    @overload
+    def __getitem__(self, idx: slice) -> "Headers":
+        ...
+
+    def __getitem__(
+        self, idx: Union[int, slice]
+    ) -> Union[Tuple[bytes, bytes], "Headers"]:
+        if isinstance(idx, slice):
+            return Headers(self._full_items[idx])
         _, name, value = self._full_items[idx]
         return (name, value)
 
diff --git a/h11/tests/test_headers.py b/h11/tests/test_headers.py
index b57274c..b6f65bd 100644
--- a/h11/tests/test_headers.py
+++ b/h11/tests/test_headers.py
@@ -11,6 +11,34 @@
 from .._util import LocalProtocolError
 
 
+@pytest.mark.parametrize(
+    "index",
+    [
+        slice(None, 1),
+        slice(None, 3),
+        slice(1, 1),
+        slice(None, None, -1),
+        slice(None, None, 2),
+    ],
+)
+def test_headers_slicing(index: slice) -> None:
+    headers = Request(
+        method="GET",
+        target="/",
+        headers=[("Host", "example.org"), ("X-First", "one"), ("X-Second", "two")],
+    ).headers
+    items = list(headers)
+    raw_items = headers.raw_items()
+
+    sliced = headers[index]
+
+    assert isinstance(sliced, Headers)
+    assert list(sliced) == items[index]
+    assert sliced.raw_items() == raw_items[index]
+    assert list(headers) == items
+    assert headers.raw_items() == raw_items
+
+
 def test_normalize_and_validate() -> None:
     assert normalize_and_validate([("foo", "bar")]) == [(b"foo", b"bar")]
     assert normalize_and_validate([(b"foo", b"bar")]) == [(b"foo", b"bar")]
diff --git a/newsfragments/headers-slicing.bugfix.rst b/newsfragments/headers-slicing.bugfix.rst
new file mode 100644
index 0000000..8c5f108
--- /dev/null
+++ b/newsfragments/headers-slicing.bugfix.rst
@@ -0,0 +1 @@
+Support slicing the header sequence exposed by events, retaining normalized header pairs and original header-name casing.

From 105816d8e70b316aff04791b0cef692e81c7d81f Mon Sep 17 00:00:00 2001
From: Huanyi Xie <74809554+xiehuanyi@users.noreply.github.com>
Date: Sun, 11 Oct 2026 15:17:34 +0300
Subject: [PATCH 2/2] Name release note after pull request 209

---
 newsfragments/{headers-slicing.bugfix.rst => 209.bugfix.rst} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename newsfragments/{headers-slicing.bugfix.rst => 209.bugfix.rst} (100%)

diff --git a/newsfragments/headers-slicing.bugfix.rst b/newsfragments/209.bugfix.rst
similarity index 100%
rename from newsfragments/headers-slicing.bugfix.rst
rename to newsfragments/209.bugfix.rst