From bbec18097e3f31b8b2d2ea08f76dc3c1ca859167 Mon Sep 17 00:00:00 2001
From: jay-choe <jay0764@naver.com>
Date: Wed, 18 Sep 2024 15:52:42 +0900
Subject: [PATCH] Remove Content-Type Header when request with empty body POST
 method (Default Client).

- add Content-Length Header with 0 value when `sun.net.http.allowRestrictedHeaders` System Property is set true

- fix not running test to run
---
 core/src/main/java/feign/Client.java          | 12 +++++------
 .../java/feign/client/DefaultClientTest.java  | 21 +++++++++++++++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/core/src/main/java/feign/Client.java b/core/src/main/java/feign/Client.java
index 93a17dd90..bd21792f5 100644
--- a/core/src/main/java/feign/Client.java
+++ b/core/src/main/java/feign/Client.java
@@ -201,19 +201,14 @@ else if (field.equals(ACCEPT_ENCODING)) {
         connection.addRequestProperty("Accept", "*/*");
       }
 
-      boolean hasEmptyBody = false;
       byte[] body = request.body();
-      if (body == null && request.httpMethod().isWithBody()) {
-        body = new byte[0];
-        hasEmptyBody = true;
-      }
 
       if (body != null) {
         /*
          * Ignore disableRequestBuffering flag if the empty body was set, to ensure that internal
          * retry logic applies to such requests.
          */
-        if (disableRequestBuffering && !hasEmptyBody) {
+        if (disableRequestBuffering) {
           if (contentLength != null) {
             connection.setFixedLengthStreamingMode(contentLength);
           } else {
@@ -236,6 +231,11 @@ else if (field.equals(ACCEPT_ENCODING)) {
           }
         }
       }
+
+      if (body == null && request.httpMethod().isWithBody()) {
+        connection.addRequestProperty("Content-Length", "0");
+      }
+
       return connection;
     }
 
diff --git a/core/src/test/java/feign/client/DefaultClientTest.java b/core/src/test/java/feign/client/DefaultClientTest.java
index c8ee70a17..c8fccfb0d 100644
--- a/core/src/test/java/feign/client/DefaultClientTest.java
+++ b/core/src/test/java/feign/client/DefaultClientTest.java
@@ -28,6 +28,7 @@
 import feign.assertj.MockWebServerAssertions;
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.SocketPolicy;
+import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
 
 /**
  * Tests client-specific behavior, such as ensuring Content-Length is sent when specified.
@@ -79,17 +80,37 @@ public void patch() throws Exception {
     assertThat(exception).hasCauseInstanceOf(ProtocolException.class);
   }
 
+  @Test
   @Override
   public void noResponseBodyForPost() throws Exception {
     super.noResponseBodyForPost();
     MockWebServerAssertions.assertThat(server.takeRequest()).hasMethod("POST")
+        .hasNoHeaderNamed("Content-Type");
+  }
+
+  @Test
+  @EnabledIfSystemProperty(named = "sun.net.http.allowRestrictedHeaders", matches = "true")
+  public void noRequestBodyForPostWithAllowRestrictedHeaders() throws Exception {
+    super.noResponseBodyForPost();
+    MockWebServerAssertions.assertThat(server.takeRequest()).hasMethod("POST")
+        .hasNoHeaderNamed("Content-Type")
         .hasHeaders(entry("Content-Length", Collections.singletonList("0")));
   }
 
+  @Test
   @Override
   public void noResponseBodyForPut() throws Exception {
     super.noResponseBodyForPut();
     MockWebServerAssertions.assertThat(server.takeRequest()).hasMethod("PUT")
+        .hasNoHeaderNamed("Content-Type");
+  }
+
+  @Test
+  @EnabledIfSystemProperty(named = "sun.net.http.allowRestrictedHeaders", matches = "true")
+  public void noResponseBodyForPutWithAllowRestrictedHeaders() throws Exception {
+    super.noResponseBodyForPut();
+    MockWebServerAssertions.assertThat(server.takeRequest()).hasMethod("PUT")
+        .hasNoHeaderNamed("Content-Type")
         .hasHeaders(entry("Content-Length", Collections.singletonList("0")));
   }