Copilot commented on code in PR #13116:
URL: https://github.com/apache/trafficserver/pull/13116#discussion_r3133246873
##########
src/proxy/http/HttpSM.cc:
##########
@@ -1687,9 +1687,23 @@ HttpSM::handle_api_return()
switch (t_state.next_action) {
case HttpTransact::StateMachineAction_t::TRANSFORM_READ: {
- HttpTunnelProducer *p = setup_transfer_from_transform();
- perform_transform_cache_write_action();
- tunnel.tunnel_run(p);
+ if (t_state.internal_msg_buffer && !t_state.api_server_request_body_set) {
+ SMDbg(dbg_ctl_http, "plugin set internal body, bypassing response
transform for internal transfer");
+ transform_info.vc = nullptr;
+ t_state.api_info.cache_untransformed = true;
+ if (t_state.hdr_info.client_response.valid() == 0 &&
t_state.hdr_info.transform_response.valid()) {
Review Comment:
In this TRANSFORM_READ branch, the server→transform tunnel is typically
already running (started in setup_server_transfer_to_transform). Calling
setup_internal_transfer() will internally call tunnel.reset(), which asserts
that the tunnel is inactive; this can crash (or corrupt tunnel state) if a
plugin sets an internal body at SEND_RESPONSE_HDR time while a response
transform is active. Consider aborting/killing the existing tunnel and cleaning
up the transform VC/entry before switching to internal transfer, or move the
bypass decision earlier (before starting the server→transform tunnel) so
internal transfer is only set up when the tunnel is inactive.
##########
doc/admin-guide/plugins/header_rewrite.en.rst:
##########
@@ -1177,8 +1177,23 @@ set-body
set-body <text>
-Sets the body to ``<text>``. Can also be used to delete a body with ``""``.
This is only useful when overriding the origin status, i.e.
-intercepting/pre-empting a request so that you can override the body from the
body-factory with your own.
+Sets the body to ``<text>``. Can also be used to delete a body with ``""``.
+
+For origin response replacement, ``set-body`` is supported at both
+``READ_RESPONSE_HDR_HOOK`` and ``SEND_RESPONSE_HDR_HOOK``. Prefer
+``READ_RESPONSE_HDR_HOOK`` when possible so body replacement happens before
+response body tunneling starts.
+
+.. note::
+
+ When ``set-body`` replaces an origin response body, ATS emits the
replacement
+ through its internal error-body path. ``Content-Type`` defaults to
+ ``text/html`` unless you override it with ``set-header Content-Type``.
+ Also, ``set-body ""`` does not suppress an origin response body on this
hook;
+ use a non-empty replacement value when sanitizing origin responses.
Review Comment:
This section is a bit self-contradictory: it says `set-body ""` can be used
to delete a body, but then notes that `set-body ""` does not suppress an origin
response body at this hook. Consider clarifying that the empty-string behavior
only deletes the synthetic/internal error body (i.e., clears
`internal_msg_buffer`), and therefore won’t remove an origin response body
unless a non-empty replacement is provided.
##########
tests/gold_tests/pluginTest/header_rewrite/header_rewrite_set_body_origin.replay.yaml:
##########
@@ -0,0 +1,345 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+meta:
+ version: "1.0"
+
+autest:
+ description: 'Test set-body origin replacement without response transforms'
+
+ dns:
+ name: 'dns'
+
+ server:
+ name: 'server'
+
+ client:
+ name: 'client'
+ process_config:
+ other_args: '--thread-limit 1'
+
+ ats:
+ name: 'ts'
+
+ plugin_config:
+ - null_transform.so
+
+ copy_to_config_dir:
+ - 'rules'
+
+ records_config:
+ proxy.config.http.insert_response_via_str: 0
+ proxy.config.http.cache.http: 0
+ proxy.config.diags.debug.enabled: 1
+ proxy.config.diags.debug.tags: 'http|header_rewrite'
+
+ remap_config:
+ # Block 1: READ_RESPONSE hook replacement path (no transform plugin).
+ - from: "http://www.example.com/set_body_read_resp_403/";
+ to: "http://backend.ex:{SERVER_HTTP_PORT}/origin_read_403/";
+ plugins:
+ - name: "header_rewrite.so"
+ args:
+ - "rules/rule_set_body_origin_read_resp.conf"
+
+ # Block 2: SEND_RESPONSE hook replacement path (no transform plugin).
+ - from: "http://www.example.com/set_body_send_resp_403/";
+ to: "http://backend.ex:{SERVER_HTTP_PORT}/origin_send_403/";
+ plugins:
+ - name: "header_rewrite.so"
+ args:
+ - "rules/rule_set_body_origin_send_resp.conf"
+
+ # Block 3a: cache-bypass probe for READ_RESPONSE hook (same URL twice).
+ - from: "http://www.example.com/cache_probe_read/";
+ to: "http://backend.ex:{SERVER_HTTP_PORT}/cache_probe_read/";
+ plugins:
+ - name: "header_rewrite.so"
+ args:
+ - "rules/rule_set_body_origin_read_resp.conf"
+
+ # Block 3b: cache-bypass probe for SEND_RESPONSE hook (same URL twice).
+ - from: "http://www.example.com/cache_probe_send/";
+ to: "http://backend.ex:{SERVER_HTTP_PORT}/cache_probe_send/";
+ plugins:
+ - name: "header_rewrite.so"
+ args:
+ - "rules/rule_set_body_origin_send_resp.conf"
+
+ # Block 4a: READ_RESPONSE hook with response transform plugin active.
+ - from: "http://www.example.com/set_body_transform_read/";
+ to: "http://backend.ex:{SERVER_HTTP_PORT}/origin_transform_read/";
+ plugins:
+ - name: "header_rewrite.so"
+ args:
+ - "rules/rule_set_body_origin_read_resp.conf"
+
+ # Block 4b: SEND_RESPONSE hook with response transform plugin active.
+ - from: "http://www.example.com/set_body_transform_send/";
+ to: "http://backend.ex:{SERVER_HTTP_PORT}/origin_transform_send/";
+ plugins:
+ - name: "header_rewrite.so"
+ args:
+ - "rules/rule_set_body_origin_send_resp.conf"
+
+sessions:
+
+- transactions:
+ # Block 1 verification: READ_RESPONSE hook replacement.
+ - client-request:
+ method: "GET"
+ version: "1.1"
+ url: /set_body_read_resp_403/
+ headers:
+ fields:
+ - [ Host, www.example.com ]
+ - [ uuid, 1 ]
+
+ server-response:
+ status: 403
+ reason: Forbidden
+ headers:
+ fields:
+ - [ Content-Length, "40" ]
+ - [ Content-Type, "text/plain" ]
+ content:
+ size: 40
+ data: "Sensitive account info: secret-key-12345"
+
+ proxy-response:
+ status: 403
+ headers:
+ fields:
+ - [ Content-Length, { value: "9", as: equal } ]
+ - [ Content-Type, { value: "text/html", as: equal } ]
+ content:
+ size: 9
+ data: "Sanitized"
+
+ # Block 2 verification: SEND_RESPONSE hook replacement.
+ - client-request:
+ method: "GET"
+ version: "1.1"
+ url: /set_body_send_resp_403/
+ headers:
+ fields:
+ - [ Host, www.example.com ]
+ - [ uuid, 2 ]
+
+ server-response:
+ status: 403
+ reason: Forbidden
+ headers:
+ fields:
+ - [ Content-Length, "40" ]
+ - [ Content-Type, "text/plain" ]
+ content:
+ size: 40
+ data: "Sensitive account info: secret-key-12345"
+
+ proxy-response:
+ status: 403
+ headers:
+ fields:
+ - [ Content-Length, { value: "9", as: equal } ]
+ - [ Content-Type, { value: "text/html", as: equal } ]
+ content:
+ size: 9
+ data: "Sanitized"
+
+ # Block 3a verification: cache-bypass probe for READ_RESPONSE.
+ # First response on repeated URL.
+ - client-request:
+ method: "GET"
+ version: "1.1"
+ url: /cache_probe_read/
+ headers:
+ fields:
+ - [ Host, www.example.com ]
+ - [ uuid, 3 ]
+
+ server-response:
+ status: 403
+ reason: Forbidden
+ headers:
+ fields:
+ - [ Content-Length, "5" ]
+ - [ Content-Type, "text/plain" ]
+ content:
+ size: 5
+ data: "first"
+
+ proxy-response:
+ status: 403
+ headers:
+ fields:
+ - [ Content-Length, { value: "9", as: equal } ]
+ content:
+ size: 9
+ data: "Sanitized"
+
+ # Block 3a verification: cache-bypass probe for READ_RESPONSE.
+ # Second response on repeated URL should still be replaced.
+ - client-request:
+ method: "GET"
+ version: "1.1"
+ url: /cache_probe_read/
+ headers:
+ fields:
+ - [ Host, www.example.com ]
+ - [ uuid, 4 ]
+
+ server-response:
+ status: 200
+ reason: OK
+ headers:
Review Comment:
These cache-probe transactions are labeled as part of the “no transform”
matrix, but the replay config globally loads null_transform.so (which adds a
response transform for 200 OK responses). With status=200 here, the second
request will likely run with a transform active, so this doesn’t actually
validate the intended no-transform path. Consider using a non-200 status for
the probe (or otherwise preventing the transform from being installed) if the
goal is to keep this block transform-free.
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