2025-12-25 upload

venv/Lib/site-packages/mitmproxy/addons/disable_h2c.py

@@ -0,0 +1,42 @@
+import logging
+
+
+class DisableH2C:
+    """
+    We currently only support HTTP/2 over a TLS connection.
+
+    Some clients try to upgrade a connection from HTTP/1.1 to h2c. We need to
+    remove those headers to avoid protocol errors if one endpoints suddenly
+    starts sending HTTP/2 frames.
+
+    Some clients might use HTTP/2 Prior Knowledge to directly initiate a session
+    by sending the connection preface. We just kill those flows.
+    """
+
+    def process_flow(self, f):
+        if f.request.headers.get("upgrade", "") == "h2c":
+            logging.warning(
+                "HTTP/2 cleartext connections (h2c upgrade requests) are currently not supported."
+            )
+            del f.request.headers["upgrade"]
+            if "connection" in f.request.headers:
+                del f.request.headers["connection"]
+            if "http2-settings" in f.request.headers:
+                del f.request.headers["http2-settings"]
+
+        is_connection_preface = (
+            f.request.method == "PRI"
+            and f.request.path == "*"
+            and f.request.http_version == "HTTP/2.0"
+        )
+        if is_connection_preface:
+            if f.killable:
+                f.kill()
+            logging.warning(
+                "Initiating HTTP/2 connections with prior knowledge are currently not supported."
+            )
+
+    # Handlers
+
+    def request(self, f):
+        self.process_flow(f)