From 52e19d5c631d9cbe6cc41b5ea34d7493160f26ee Mon Sep 17 00:00:00 2001
From: Daniel Schobel <dschobel@twitter.com>
Date: Thu, 10 Aug 2017 17:50:00 -0600
Subject: [PATCH] Strip http 'expect' headers when expectation response is
 produced

Motivation:

HttpObjectAggregator differs from HttpServerExpectContinueHandler's handling
of expect headers by not stripping the 'expect' header when a response
is generated.

Modifications:

HttpObjectAggregator now removes the 'expect' header in cases where it generates
a response.

Result:

Consistent and correct behavior between HttpObjectAggregator and HttpServerExpectContinueHandler.
---
 .../codec/http/HttpObjectAggregator.java        | 15 +++++++++++++--
 .../codec/http/HttpObjectAggregatorTest.java    | 17 +++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectAggregator.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectAggregator.java
index 3b3fa42207..0b8bc2e29b 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectAggregator.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectAggregator.java
@@ -30,6 +30,7 @@ import io.netty.util.internal.logging.InternalLoggerFactory;
 
 import static io.netty.handler.codec.http.HttpHeaderNames.CONNECTION;
 import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
+import static io.netty.handler.codec.http.HttpHeaderNames.EXPECT;
 import static io.netty.handler.codec.http.HttpUtil.getContentLength;
 
 /**
@@ -158,8 +159,7 @@ public class HttpObjectAggregator
         }
     }
 
-    @Override
-    protected Object newContinueResponse(HttpMessage start, int maxContentLength, ChannelPipeline pipeline) {
+    private Object continueResponse(HttpMessage start, int maxContentLength, ChannelPipeline pipeline) {
         if (HttpUtil.isUnsupportedExpectation(start)) {
             // if the request contains an unsupported expectation, we return 417
             pipeline.fireUserEventTriggered(HttpExpectationFailedEvent.INSTANCE);
@@ -176,6 +176,17 @@ public class HttpObjectAggregator
         return null;
     }
 
+    @Override
+    protected Object newContinueResponse(HttpMessage start, int maxContentLength, ChannelPipeline pipeline) {
+        Object response = continueResponse(start, maxContentLength, pipeline);
+        // we're going to respond based on the request expectation so there's no
+        // need to propagate the expectation further.
+        if (response != null) {
+            start.headers().remove(EXPECT);
+        }
+        return response;
+    }
+
     @Override
     protected boolean closeAfterContinueResponse(Object msg) {
         return closeOnExpectationFailed && ignoreContentAfterContinueResponse(msg);
diff --git a/codec-http/src/test/java/io/netty/handler/codec/http/HttpObjectAggregatorTest.java b/codec-http/src/test/java/io/netty/handler/codec/http/HttpObjectAggregatorTest.java
index 8a100a7680..7dc0ac5a51 100644
--- a/codec-http/src/test/java/io/netty/handler/codec/http/HttpObjectAggregatorTest.java
+++ b/codec-http/src/test/java/io/netty/handler/codec/http/HttpObjectAggregatorTest.java
@@ -370,6 +370,23 @@ public class HttpObjectAggregatorTest {
         assertFalse(embedder.finish());
     }
 
+    @Test
+    public void testValidRequestWith100ContinueAndDecoder() {
+        EmbeddedChannel embedder = new EmbeddedChannel(new HttpRequestDecoder(), new HttpObjectAggregator(100));
+        embedder.writeInbound(Unpooled.copiedBuffer(
+            "GET /upload HTTP/1.1\r\n" +
+                "Expect: 100-continue\r\n" +
+                "Content-Length: 0\r\n\r\n", CharsetUtil.US_ASCII));
+
+        FullHttpResponse response = embedder.readOutbound();
+        assertEquals(HttpResponseStatus.CONTINUE, response.status());
+        FullHttpRequest request = embedder.readInbound();
+        assertFalse(request.headers().contains(HttpHeaderNames.EXPECT));
+        request.release();
+        response.release();
+        assertFalse(embedder.finish());
+    }
+
     @Test
     public void testOversizedRequestWith100ContinueAndDecoder() {
         EmbeddedChannel embedder = new EmbeddedChannel(new HttpRequestDecoder(), new HttpObjectAggregator(4));