Netty 4 Does Not Send Request Body

[lukasniemeier-zalando]

When using Netty4ClientHttpRequestFactory request bodies are not send to the server.

Expected Behavior

Request body is transmitted.

Actual Behavior

Server observes empty request body.

Steps to Reproduce

See a85ce45.

Your Environment

• Version used: 797dc47

[lukasniemeier-zalando]

Curiously request bodies are send/flushed when calling close on the body stream, like it's proposed for the request compression plugin in

riptide/riptide-compression/src/main/java/org/zalando/riptide/compression/RequestCompressionPlugin.java

Lines 68 to 71 in f2dde3c

	try (final WrappingHttpOutputMessage compressingMessage =
	new WrappingHttpOutputMessage(message, compression.getOutputStreamDecorator())) {
	entity.writeTo(compressingMessage);
	}

.

[whiskeysierra]

Might be related to spring-projects/spring-framework#19426

[whiskeysierra]

If I enable the factory in the request compression test it fails in mysterious ways:

Spring 4.x

• ✔️ shouldCompressWithGivenAlgorithm
• ✔️ shouldCompressRequestBody
• ❌ shouldBackOffIfAlreadyEncoded
• ✔️ shouldNotCompressEmptyRequestBody

Spring 5.x

• ❌ shouldCompressWithGivenAlgorithm
• ❌ shouldCompressRequestBody
• ✔️ shouldBackOffIfAlreadyEncoded
• ✔️ shouldNotCompressEmptyRequestBody

[whiskeysierra]

The following was added in between 4.x and 5.x within the Netty4ClientHttpRequest and fixes the issue in Spring 4.x:

if (!nettyRequest.headers().contains(HttpHeaders.CONTENT_LENGTH) && this.body.buffer().readableBytes() > 0) {
	nettyRequest.headers().set(HttpHeaders.CONTENT_LENGTH, this.body.buffer().readableBytes());
}

Since that seems to be an issue in Spring I'd say it's not our task to fix. The issues in 5.x could be related to our compression and headers though. My idea was that we set the wrong content length and somehow the whole request is not send. But I can't prove that using the debugger.

[lukasniemeier-zalando]

The following was added in between 4.x and 5.x within the Netty4ClientHttpRequest and fixes the issue in Spring 4.x

Which is funny, see #822 (comment)

[whiskeysierra]

spring-projects/spring-framework@ec8391a#diff-f6d905d4521bc40e2eadc060adb89078