http.lua: allow setting HTTP1 reason phrase (#22847)

Signed-off-by: Max Kuznetsov <[email protected]>

changelogs/current.yaml

@@ -134,6 +134,9 @@ new_features:
   change: |
     added the expected :ref:`receive <envoy_v3_api_field_config.core.v3.HealthCheck.HttpHealthCheck.receive>` payload check for HTTP health check.
     Added :ref:`response_buffer_size <envoy_v3_api_field_config.core.v3.HealthCheck.HttpHealthCheck.response_buffer_size>` to configure the maximum HTTP health check response buffer size.
+- area: lua
+  change: |
+    added new headers method "setHttp1ReasonPhrase" for lua filter, please see :ref:`lua header wrapper <config_http_filters_lua_header_wrapper>`.
 - area: lua
   change: |
     added stats for lua filter, please see :ref:`lua filter stats <config_http_filters_lua_stats>`.

docs/root/configuration/http/http_filters/lua_filter.rst

@@ -692,6 +692,17 @@ replace()
 Replaces a header. *key* is a string that supplies the header key. *value* is a string that supplies
 the header value. If the header does not exist, it is added as per the *add()* function.
 
+setHttp1ReasonPhrase()
+^^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block:: lua
+
+  headers:setHttp1ReasonPhrase(reasonPhrase)
+
+Sets a custom HTTP/1 response reason phrase. This call is *only valid in the response flow*.
+*reasonPhrase* is a string that supplies the reason phrase value. Additionally this call only
+effects HTTP/1 connections. It will have no effect if the client is HTTP/2 or HTTP/3.
+
 .. _config_http_filters_lua_buffer_wrapper:
 
 Buffer API

source/extensions/filters/http/lua/BUILD

@@ -45,6 +45,7 @@ envoy_cc_library(
         "//source/common/http:utility_lib",
         "//source/extensions/filters/common/lua:lua_lib",
         "//source/extensions/filters/common/lua:wrappers_lib",
+        "//source/extensions/http/header_formatters/preserve_case:preserve_case_formatter",
     ],
 )
 

source/extensions/filters/http/lua/wrappers.cc

@@ -1,8 +1,10 @@
 #include "source/extensions/filters/http/lua/wrappers.h"
 
+#include "source/common/http/header_map_impl.h"
 #include "source/common/http/header_utility.h"
 #include "source/common/http/utility.h"
 #include "source/extensions/filters/common/lua/wrappers.h"
+#include "source/extensions/http/header_formatters/preserve_case/preserve_case_formatter.h"
 
 namespace Envoy {
 namespace Extensions {
@@ -11,10 +13,11 @@ namespace Lua {
 
 HeaderMapIterator::HeaderMapIterator(HeaderMapWrapper& parent) : parent_(parent) {
   entries_.reserve(parent_.headers_.size());
-  parent_.headers_.iterate([this](const Http::HeaderEntry& header) -> Http::HeaderMap::Iterate {
-    entries_.push_back(&header);
-    return Http::HeaderMap::Iterate::Continue;
-  });
+  parent_.headers_.iterate(
+      [this](const Envoy::Http::HeaderEntry& header) -> Envoy::Http::HeaderMap::Iterate {
+        entries_.push_back(&header);
+        return Envoy::Http::HeaderMap::Iterate::Continue;
+      });
 }
 
 int HeaderMapIterator::luaPairsIterator(lua_State* state) {
@@ -36,14 +39,15 @@ int HeaderMapWrapper::luaAdd(lua_State* state) {
 
   const char* key = luaL_checkstring(state, 2);
   const char* value = luaL_checkstring(state, 3);
-  headers_.addCopy(Http::LowerCaseString(key), value);
+  headers_.addCopy(Envoy::Http::LowerCaseString(key), value);
   return 0;
 }
 
 int HeaderMapWrapper::luaGet(lua_State* state) {
   absl::string_view key = Filters::Common::Lua::getStringViewFromLuaString(state, 2);
-  const Http::HeaderUtility::GetAllOfHeaderAsStringResult value =
-      Http::HeaderUtility::getAllOfHeaderAsString(headers_, Http::LowerCaseString(key));
+  const Envoy::Http::HeaderUtility::GetAllOfHeaderAsStringResult value =
+      Envoy::Http::HeaderUtility::getAllOfHeaderAsString(headers_,
+                                                         Envoy::Http::LowerCaseString(key));
   if (value.result().has_value()) {
     lua_pushlstring(state, value.result().value().data(), value.result().value().size());
     return 1;
@@ -55,7 +59,8 @@ int HeaderMapWrapper::luaGet(lua_State* state) {
 int HeaderMapWrapper::luaGetAtIndex(lua_State* state) {
   absl::string_view key = Filters::Common::Lua::getStringViewFromLuaString(state, 2);
   const int index = luaL_checknumber(state, 3);
-  const Http::HeaderMap::GetResult header_value = headers_.get(Http::LowerCaseString(key));
+  const Envoy::Http::HeaderMap::GetResult header_value =
+      headers_.get(Envoy::Http::LowerCaseString(key));
   if (index >= 0 && header_value.size() > static_cast<uint64_t>(index)) {
     absl::string_view value = header_value[index]->value().getStringView();
     lua_pushlstring(state, value.data(), value.size());
@@ -66,7 +71,8 @@ int HeaderMapWrapper::luaGetAtIndex(lua_State* state) {
 
 int HeaderMapWrapper::luaGetNumValues(lua_State* state) {
   absl::string_view key = Filters::Common::Lua::getStringViewFromLuaString(state, 2);
-  const Http::HeaderMap::GetResult header_value = headers_.get(Http::LowerCaseString(key));
+  const Envoy::Http::HeaderMap::GetResult header_value =
+      headers_.get(Envoy::Http::LowerCaseString(key));
   lua_pushnumber(state, header_value.size());
   return 1;
 }
@@ -93,7 +99,7 @@ int HeaderMapWrapper::luaReplace(lua_State* state) {
 
   const char* key = luaL_checkstring(state, 2);
   const char* value = luaL_checkstring(state, 3);
-  const Http::LowerCaseString lower_key(key);
+  const Envoy::Http::LowerCaseString lower_key(key);
 
   headers_.setCopy(lower_key, value);
 
@@ -104,7 +110,7 @@ int HeaderMapWrapper::luaRemove(lua_State* state) {
   checkModifiable(state);
 
   const char* key = luaL_checkstring(state, 2);
-  headers_.remove(Http::LowerCaseString(key));
+  headers_.remove(Envoy::Http::LowerCaseString(key));
   return 0;
 }
 
@@ -118,8 +124,39 @@ void HeaderMapWrapper::checkModifiable(lua_State* state) {
   }
 }
 
+int HeaderMapWrapper::luaSetHttp1ReasonPhrase(lua_State* state) {
+  checkModifiable(state);
+
+  size_t input_size = 0;
+  const char* phrase = luaL_checklstring(state, 2, &input_size);
+
+  Envoy::Http::StatefulHeaderKeyFormatterOptRef formatter(headers_.formatter());
+
+  if (!formatter.has_value()) {
+    using envoy::extensions::http::header_formatters::preserve_case::v3::
+        PreserveCaseFormatterConfig;
+    using Envoy::Http::ResponseHeaderMapImpl;
+    using Envoy::Http::StatefulHeaderKeyFormatter;
+    using Http::HeaderFormatters::PreserveCase::PreserveCaseHeaderFormatter;
+
+    // Casting here to make sure the call is in the right (response) context
+    ResponseHeaderMapImpl* map = dynamic_cast<ResponseHeaderMapImpl*>(&headers_);
+    if (map) {
+      std::unique_ptr<StatefulHeaderKeyFormatter> fmt =
+          std::make_unique<PreserveCaseHeaderFormatter>(true, PreserveCaseFormatterConfig::DEFAULT);
+      fmt->setReasonPhrase(absl::string_view(phrase, input_size));
+      map->setFormatter(std::move(fmt));
+    }
+  } else {
+    formatter->setReasonPhrase(absl::string_view(phrase, input_size));
+  }
+
+  return 0;
+}
+
 int StreamInfoWrapper::luaProtocol(lua_State* state) {
-  const std::string& protocol = Http::Utility::getProtocolString(stream_info_.protocol().value());
+  const std::string& protocol =
+      Envoy::Http::Utility::getProtocolString(stream_info_.protocol().value());
   lua_pushlstring(state, protocol.data(), protocol.size());
   return 1;
 }

source/extensions/filters/http/lua/wrappers.h

@@ -50,6 +50,7 @@ class HeaderMapWrapper : public Filters::Common::Lua::BaseLuaObject<HeaderMapWra
             {"getNumValues", static_luaGetNumValues},
             {"remove", static_luaRemove},
             {"replace", static_luaReplace},
+            {"setHttp1ReasonPhrase", static_luaSetHttp1ReasonPhrase},
             {"__pairs", static_luaPairs}};
   }
 
@@ -105,6 +106,13 @@ class HeaderMapWrapper : public Filters::Common::Lua::BaseLuaObject<HeaderMapWra
    */
   DECLARE_LUA_FUNCTION(HeaderMapWrapper, luaReplace);
 
+  /**
+   * Set a HTTP1 reason phrase
+   * @param 1 (string): reason phrase
+   * @return nothing.
+   */
+  DECLARE_LUA_FUNCTION(HeaderMapWrapper, luaSetHttp1ReasonPhrase);
+
   void checkModifiable(lua_State* state);
 
   // Envoy::Lua::BaseLuaObject

test/extensions/filters/http/lua/lua_integration_test.cc

@@ -1235,5 +1235,26 @@ name: lua
   testRewriteResponse(FILTER_AND_CODE);
 }
 
+// Test whether setting the HTTP1 reason phrase
+TEST_P(LuaIntegrationTest, Http1ReasonPhrase) {
+  const std::string FILTER_AND_CODE =
+      R"EOF(
+name: lua
+typed_config:
+  "@type": type.googleapis.com/envoy.extensions.filters.http.lua.v3.Lua
+  default_source_code:
+    inline_string: |
+      function envoy_on_response(response_handle)
+        response_handle:headers():setHttp1ReasonPhrase("Slow Down")
+      end
+)EOF";
+
+  initializeFilter(FILTER_AND_CODE);
+
+  std::string response;
+  sendRawHttpAndWaitForResponse(lookupPort("http"), "GET / HTTP/1.1\r\n\r\n", &response, true);
+  EXPECT_TRUE(response.find("HTTP/1.1 400 Slow Down\r\n") == 0);
+}
+
 } // namespace
 } // namespace Envoy

test/extensions/filters/http/lua/wrappers_test.cc

@@ -276,6 +276,26 @@ TEST_F(LuaHeaderMapWrapperTest, IteratorAcrossYield) {
                             "[string \"...\"]:5: object used outside of proper scope");
 }
 
+// Verify setting the HTTP1 reason phrase
+TEST_F(LuaHeaderMapWrapperTest, SetHttp1ReasonPhrase) {
+  const std::string SCRIPT{R"EOF(
+    function callMe(object)
+      object:setHttp1ReasonPhrase("Slow Down")
+    end
+  )EOF"};
+
+  InSequence s;
+  setup(SCRIPT);
+
+  auto headers = Http::ResponseHeaderMapImpl::create();
+  HeaderMapWrapper::create(coroutine_->luaState(), *headers, []() { return true; });
+  start("callMe");
+
+  Http::StatefulHeaderKeyFormatterOptRef formatter(headers->formatter());
+  EXPECT_EQ(true, formatter.has_value());
+  EXPECT_EQ("Slow Down", formatter->getReasonPhrase());
+}
+
 class LuaStreamInfoWrapperTest
     : public Filters::Common::Lua::LuaWrappersTestBase<StreamInfoWrapper> {
 public: