When compression is enabled via a predicate the response body is not compressed

[wilkinsona]

Expected behavior

The response body is compressed when the headers state that it is.

Actual behavior

The response body is not compressed.

Steps to reproduce

Apply the following diff to 0.7.x:

diff --git a/src/test/java/reactor/ipc/netty/http/server/HttpSendFileTests.java b/src/test/java/reactor/ipc/netty/http/server/HttpSendFileTests.java
index 87114cd..8dff809 100644
--- a/src/test/java/reactor/ipc/netty/http/server/HttpSendFileTests.java
+++ b/src/test/java/reactor/ipc/netty/http/server/HttpSendFileTests.java
@@ -115,6 +115,20 @@ public class HttpSendFileTests {
                }
        }

+       @Test
+       public void sendZipFileCompressionPredicate() throws IOException {
+               Path path = Files.createTempFile(null, ".zip");
+               Files.copy(this.getClass().getResourceAsStream("/zipFile.zip"), path, StandardCopyOption.REPLACE_EXISTING);
+               path.toFile().deleteOnExit();
+
+               try (FileSystem zipFs = FileSystems.newFileSystem(path, null)) {
+                       Path fromZipFile = zipFs.getPath("/largeFile.txt");
+                       long fileSize = Files.size(fromZipFile);
+
+                       assertSendFile(out -> out.sendFile(fromZipFile, 0, fileSize), true);
+               }
+       }
+
        private void assertSendFile(Function<HttpServerResponse, NettyOutbound> fn) {
                assertSendFile(fn, false);
        }
@@ -130,7 +144,7 @@ public class HttpSendFileTests {

        private void assertSendFile(Function<HttpServerResponse, NettyOutbound> fn, boolean compression, Consumer<String> bodyAssertion) {
                NettyContext context =
-                               HttpServer.create(opt -> customizeServerOptions(opt.host("localhost")))
+                               HttpServer.create(opt -> customizeServerOptions(opt.host("localhost").compression((req, resp) -> true)))
                                          .newHandler((req, resp) -> fn.apply(resp))
                                          .block();

The intent of the new test is to use the predicate that's used to configure the server options to dictate whether or not the response is compressed. If you run it, it should fail like this:

reactor.ipc.netty.http.server.HttpsSendFileTests > sendZipFileCompressionPredicate FAILED
    io.netty.handler.codec.compression.DecompressionException: Input is not in the GZIP format

Alternatively, there's a less minimal example here.

Reactor Netty version

0.7.8.RELEASE

JVM version (e.g. java -version)

java version "1.8.0_151"
Java(TM) SE Runtime Environment (build 1.8.0_151-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.151-b12, mixed mode)

OS version (e.g. uname -a)

macOS

[violetagg]

Closed #411 via caa1adf