Add content compression support to StyxServer object

components/proxy/src/main/kotlin/com/hotels/styx/servers/StyxHttpServer.kt

@@ -40,6 +40,7 @@ object StyxHttpServer {
     val SCHEMA = `object`(
             field("port", integer()),
             field("handler", string()),
+            optional("compressResponses", bool()),
             optional("tlsSettings", `object`(
                     optional("sslProvider", string()),
                     optional("certificateFile", string()),
@@ -79,6 +80,7 @@ private data class StyxHttpServerTlsSettings(
 private data class StyxHttpServerConfiguration(
         val port: Int,
         val handler: String,
+        val compressResponses: Boolean,
         val tlsSettings: StyxHttpServerTlsSettings?,
 
         val maxInitialLength: Int = 4096,
@@ -101,6 +103,7 @@ internal class StyxHttpServerFactory : StyxServerFactory {
 
         val environment = context.environment()
         val proxyServerConfig = ProxyServerConfig.Builder()
+                .setCompressResponses(config.compressResponses)
                 .setMaxInitialLength(config.maxInitialLength)
                 .setMaxHeaderSize(config.maxHeaderSize)
                 .setMaxChunkSize(config.maxChunkSize)

components/proxy/src/test/kotlin/com/hotels/styx/servers/StyxHttpServerTest.kt

@@ -49,7 +49,9 @@ import io.kotlintest.specs.FeatureSpec
 import reactor.core.publisher.Flux
 import reactor.core.publisher.toFlux
 import reactor.core.publisher.toMono
+import java.nio.charset.Charset
 import java.nio.charset.StandardCharsets.UTF_8
+import java.util.zip.GZIPInputStream
 
 class StyxHttpServerTest : FeatureSpec({
     feature("HTTP request handling") {
@@ -109,6 +111,46 @@ class StyxHttpServerTest : FeatureSpec({
         }
     }
 
+    feature("Response compression") {
+
+        val serverConfig = configBlock("""
+                port: 0
+                handler: aHandler
+                compressResponses: true
+              """.trimIndent())
+
+        val server = StyxHttpServerFactory().create("test-01", routingContext, serverConfig, db)
+        val guavaServer = toGuavaService(server)
+        guavaServer.startAsync().awaitRunning()
+
+        scenario("Responses are compressed if accept-encoding is set to gzip") {
+            StyxHttpClient.Builder().build().send(get("/blah")
+                    .header(HOST, "localhost:${server.inetAddress().port}")
+                    .header("accept-encoding", "7z, gzip")
+                    .build())
+                    .wait()!!
+                    .let {
+                        it.status() shouldBe OK
+                        it.header("content-encoding").get() shouldBe "gzip"
+                        ungzip(it.body(), UTF_8) shouldBe "Hello, test!"
+                    }
+        }
+
+        scenario("Does not compress response if accept-encoding not sent") {
+            StyxHttpClient.Builder().build().send(get("/blah")
+                    .header(HOST, "localhost:${server.inetAddress().port}")
+                    .build())
+                    .wait()!!
+                    .let {
+                        it.status() shouldBe OK
+                        it.header("content-encoding").isPresent shouldBe false
+                        it.bodyAs(UTF_8) shouldBe "Hello, test!"
+                    }
+        }
+
+        guavaServer.stopAsync().awaitTerminated()
+    }
+
     feature("Max initial line length") {
         val serverConfig = configBlock("""
                 port: 0
@@ -302,12 +344,25 @@ private fun createConnection(port: Int) = NettyConnectionFactory.Builder()
 
 private val response = HttpResponse.response(OK)
         .header("source", "secure")
+        .header("content-type", "text/plain")
         .body("Hello, test!", UTF_8)
         .build()
 
+private val compressedResponse = HttpResponse.response(OK)
+        .header("source", "secure")
+        .header("content-type", "text/plain")
+        .header("content-encoding", "gzip")
+        .body("Hello, test!", UTF_8) // Not actually compressed, just claims to be, which is all we want.
+        .build()
+
 private val routingContext = RoutingObjectFactoryContext(
         routeRefLookup = routeLookup {
-            ref("aHandler" to RoutingObject { _, _ -> Eventual.of(response.stream()) })
+            ref("aHandler" to RoutingObject { request, _ ->
+                when(request.url().toString()) {
+                    "/compressed" -> Eventual.of(compressedResponse.stream())
+                    else -> Eventual.of(response.stream())
+                }
+            })
 
             ref("aggregator" to RoutingObject { request, _ ->
                 request
@@ -317,6 +372,8 @@ private val routingContext = RoutingObjectFactoryContext(
         })
         .get()
 
+private fun ungzip(content: ByteArray, charset: Charset): String = GZIPInputStream(content.inputStream()).bufferedReader(charset).use { it.readText() }
+
 private val db = StyxObjectStore<StyxObjectRecord<InetServer>>()
 
 private val crtFile = fixturesHome(StyxHttpServerTest::class.java, "/ssl/testCredentials.crt").toString()