From 64a0045743fc1f464b4bb0bc75c29755f775c828 Mon Sep 17 00:00:00 2001
From: ghdtjdwn <seongjuice999@gmail.com>
Date: Wed, 11 Nov 2026 10:29:31 +0900
Subject: [PATCH 1/2] opentelemetry-instrumentation-wsgi: capture Content-Type
 and Content-Length request headers

PEP 3333 passes these two headers as CONTENT_TYPE and CONTENT_LENGTH,
without the HTTP_ prefix, so they were never matched by
OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST.
---
 .../instrumentation/wsgi/__init__.py          |  5 ++++
 .../tests/test_wsgi_middleware.py             | 25 +++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/instrumentation/opentelemetry-instrumentation-wsgi/src/opentelemetry/instrumentation/wsgi/__init__.py b/instrumentation/opentelemetry-instrumentation-wsgi/src/opentelemetry/instrumentation/wsgi/__init__.py
index e4c969dc9f..86b94ca7fd 100644
--- a/instrumentation/opentelemetry-instrumentation-wsgi/src/opentelemetry/instrumentation/wsgi/__init__.py
+++ b/instrumentation/opentelemetry-instrumentation-wsgi/src/opentelemetry/instrumentation/wsgi/__init__.py
@@ -448,6 +448,11 @@ def collect_custom_request_headers_attributes(environ: WSGIEnvironment) -> dict[
         for key, val in environ.items()
         if key.startswith(_CARRIER_KEY_PREFIX)
     }
+    # PEP 3333: these two have no HTTP_ prefix and may be empty or absent
+    for key in ("CONTENT_TYPE", "CONTENT_LENGTH"):
+        val = environ.get(key)
+        if val:
+            headers[key.replace("_", "-")] = val
 
     return sanitize.sanitize_header_values(
         headers,
diff --git a/instrumentation/opentelemetry-instrumentation-wsgi/tests/test_wsgi_middleware.py b/instrumentation/opentelemetry-instrumentation-wsgi/tests/test_wsgi_middleware.py
index a49a35d3de..4cbfa8a6e5 100644
--- a/instrumentation/opentelemetry-instrumentation-wsgi/tests/test_wsgi_middleware.py
+++ b/instrumentation/opentelemetry-instrumentation-wsgi/tests/test_wsgi_middleware.py
@@ -1208,6 +1208,31 @@ def test_custom_request_headers_added_in_server_span(self) -> None:
                     for point in metric.data.data_points:
                         self.assertTrue(set(expected).isdisjoint(point.attributes))
 
+    @mock.patch.dict(
+        "os.environ",
+        {OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST: "Content-Type,Content-Length"},
+    )
+    def test_custom_request_headers_content_type_and_length(self) -> None:
+        self.environ.update(
+            {
+                "CONTENT_TYPE": "application/json",
+                "CONTENT_LENGTH": "7",
+                "HTTP_CONTENT_TYPE": "text/html",
+            }
+        )
+        self.assertEqual(
+            otel_wsgi.collect_custom_request_headers_attributes(self.environ),
+            {
+                "http.request.header.content_type": ["application/json"],
+                "http.request.header.content_length": ["7"],
+            },
+        )
+        self.environ["CONTENT_LENGTH"] = ""
+        self.assertEqual(
+            otel_wsgi.collect_custom_request_headers_attributes(self.environ),
+            {"http.request.header.content_type": ["application/json"]},
+        )
+
     @mock.patch.dict(
         "os.environ",
         {OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST: "Custom-Test-Header-1"},

From c5c697d31baa2476b7b8bc250eb6d83663d5d877 Mon Sep 17 00:00:00 2001
From: ghdtjdwn <seongjuice999@gmail.com>
Date: Wed, 11 Nov 2026 10:31:09 +0900
Subject: [PATCH 2/2] Add changelog fragment

---
 .changelog/5321.fixed | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 .changelog/5321.fixed

diff --git a/.changelog/5321.fixed b/.changelog/5321.fixed
new file mode 100644
index 0000000000..be4284e3b9
--- /dev/null
+++ b/.changelog/5321.fixed
@@ -0,0 +1 @@
+`opentelemetry-instrumentation-wsgi`: capture `Content-Type` and `Content-Length` request headers