1 files changed, 21 insertions, 0 deletions
diff --git a/mitmproxy/addons/disable_h2c_upgrade.py b/mitmproxy/addons/disable_h2c_upgrade.py
new file mode 100644
index 00000000..f4a36d5f
--- /dev/null
+++ b/mitmproxy/addons/disable_h2c_upgrade.py
@@ -0,0 +1,21 @@
+class DisableH2CleartextUpgrade:
+
+    """
+    We currently only support HTTP/2 over a TLS connection. Some clients try
+    to upgrade a connection from HTTP/1.1 to h2c, so we need to remove those
+    headers to avoid protocol errors if one endpoints suddenly starts sending
+    HTTP/2 frames.
+    """
+
+    def process_flow(self, f):
+        if f.request.headers.get('upgrade', '') == 'h2c':
+            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']
+
+    # Handlers
+
+    def request(self, f):
+        self.process_flow(f)