fix handling of no host header (#24)

* fix handling of no host header
* use the same route on encode as in decode
as if there is no route on decode, there will not be one on encode.

Author: yuval-k

source/extensions/filters/http/transformation/transformation_filter.cc

@@ -28,7 +28,6 @@ void TransformationFilter::onDestroy() { resetInternalState(); }
 Http::FilterHeadersStatus
 TransformationFilter::decodeHeaders(Http::HeaderMap &header_map,
                                     bool end_stream) {
-
   checkRequestActive();
 
   if (is_error()) {
@@ -86,7 +85,6 @@ TransformationFilter::decodeTrailers(Http::HeaderMap &) {
 Http::FilterHeadersStatus
 TransformationFilter::encodeHeaders(Http::HeaderMap &header_map,
                                     bool end_stream) {
-
   checkResponseActive();
 
   if (!responseActive()) {
@@ -142,7 +140,6 @@ void TransformationFilter::checkRequestActive() {
 }
 
 void TransformationFilter::checkResponseActive() {
-  route_ = encoder_callbacks_->route();
   response_transformation_ =
       getTransformFromRoute(TransformationFilter::Direction::Response);
 }

test/extensions/filters/http/transformation/transformation_filter_test.cc

@@ -36,6 +36,14 @@ class TransformationFilterTest : public testing::Test {
             perFilterConfig(SoloHttpFilterNames::get().Transformation))
         .WillByDefault(Return(route_config_wrapper_.get()));
 
+    ON_CALL(encoder_filter_callbacks_, route())
+        .WillByDefault(Invoke([this]() -> Router::RouteConstSharedPtr {
+          if (headers_.Host() == nullptr) {
+            throw std::runtime_error("no host");
+          }
+          return encoder_filter_callbacks_.route_;
+        }));
+
     filter_ = std::make_unique<TransformationFilter>();
     filter_->setDecoderFilterCallbacks(filter_callbacks_);
     filter_->setEncoderFilterCallbacks(encoder_filter_callbacks_);
@@ -116,6 +124,21 @@ TEST_F(TransformationFilterTest, TransformsResponseOnHeaders) {
   EXPECT_EQ(Http::FilterHeadersStatus::Continue, res);
 }
 
+TEST_F(TransformationFilterTest, TransformsResponseOnHeadersNoHost) {
+  headers_.remove(":authority");
+  route_config_.mutable_response_transformation()
+      ->mutable_transformation_template()
+      ->mutable_body()
+      ->set_text("solo");
+
+  initFilter();
+
+  // no encode headers to simulate local reply error.
+  EXPECT_CALL(encoder_filter_callbacks_, addEncodedData(_, false)).Times(0);
+  auto res = filter_->encodeHeaders(headers_, true);
+  EXPECT_EQ(Http::FilterHeadersStatus::Continue, res);
+}
+
 TEST_F(TransformationFilterTest, ErrorOnBadTemplate) {
   initFilterWithBodyTemplate("{{nonexistentvar}}");