Add HTTP keep-alive support

Signed-off-by: Graham <gpe@openrs2.org>

game/src/main/kotlin/org/openrs2/game/net/crossdomain/CrossDomainChannelHandler.kt

@@ -7,6 +7,7 @@ import io.netty.channel.SimpleChannelInboundHandler
 import io.netty.handler.codec.http.HttpMethod
 import io.netty.handler.codec.http.HttpRequest
 import io.netty.handler.codec.http.HttpResponseStatus
+import io.netty.handler.timeout.IdleStateEvent
 import org.openrs2.buffer.use
 import org.openrs2.game.net.http.Http
 
@@ -39,5 +40,21 @@ public object CrossDomainChannelHandler : SimpleChannelInboundHandler<HttpReques
 
     override fun channelReadComplete(ctx: ChannelHandlerContext) {
         ctx.flush()
+
+        if (ctx.channel().isWritable) {
+            ctx.read()
+        }
+    }
+
+    override fun channelWritabilityChanged(ctx: ChannelHandlerContext) {
+        if (ctx.channel().isWritable) {
+            ctx.read()
+        }
+    }
+
+    override fun userEventTriggered(ctx: ChannelHandlerContext, evt: Any) {
+        if (evt is IdleStateEvent) {
+            ctx.close()
+        }
     }
 }

game/src/main/kotlin/org/openrs2/game/net/http/Http.kt

@@ -11,15 +11,22 @@ import io.netty.handler.codec.http.HttpMethod
 import io.netty.handler.codec.http.HttpRequest
 import io.netty.handler.codec.http.HttpResponseStatus
 import io.netty.handler.codec.http.HttpVersion
+import io.netty.handler.codec.http.LastHttpContent
 import io.netty.util.ReferenceCounted
 import org.openrs2.buffer.copiedBuffer
 import org.openrs2.buffer.use
 
 public object Http {
+    public const val TIMEOUT_SECS: Long = 30
     public const val MAX_CONTENT_LENGTH: Int = 65536
     public const val TEXT_X_CROSS_DOMAIN_POLICY: String = "text/x-cross-domain-policy"
     private const val BANNER = "OpenRS2"
 
+    private fun isKeepAlive(request: HttpRequest, version: HttpVersion): Boolean {
+        val connection = request.headers().get(HttpHeaderNames.CONNECTION) ?: return version.isKeepAliveDefault
+        return HttpHeaderValues.KEEP_ALIVE.contentEquals(connection)
+    }
+
     private fun writeResponse(
         ctx: ChannelHandlerContext,
         request: HttpRequest,
@@ -34,17 +41,32 @@ public object Http {
             HttpVersion.HTTP_1_1
         }
 
+        val keepAlive = isKeepAlive(request, version)
+
         val response = DefaultHttpResponse(version, status)
-        response.headers().add(HttpHeaderNames.CONNECTION, HttpHeaderValues.CLOSE)
+        response.headers().add(HttpHeaderNames.CONNECTION, if (keepAlive) {
+            HttpHeaderValues.KEEP_ALIVE
+        } else {
+            HttpHeaderValues.CLOSE
+        })
         response.headers().add(HttpHeaderNames.SERVER, BANNER)
         response.headers().add(HttpHeaderNames.CONTENT_TYPE, contentType)
         response.headers().add(HttpHeaderNames.CONTENT_LENGTH, contentLength)
 
-        if (request.method() == HttpMethod.HEAD) {
-            ctx.write(response).addListener(ChannelFutureListener.CLOSE)
+        ctx.write(response, ctx.voidPromise())
+
+        if (request.method() != HttpMethod.HEAD) {
+            ctx.write(content.retain(), ctx.voidPromise())
+        }
+
+        writeLastChunk(ctx, keepAlive)
+    }
+
+    private fun writeLastChunk(ctx: ChannelHandlerContext, keepAlive: Boolean) {
+        if (keepAlive) {
+            ctx.write(LastHttpContent.EMPTY_LAST_CONTENT, ctx.voidPromise())
         } else {
-            ctx.write(response, ctx.voidPromise())
-            ctx.write(content.retain()).addListener(ChannelFutureListener.CLOSE)
+            ctx.write(LastHttpContent.EMPTY_LAST_CONTENT).addListener(ChannelFutureListener.CLOSE)
         }
     }
 

game/src/main/kotlin/org/openrs2/game/net/http/HttpChannelHandler.kt

@@ -6,6 +6,7 @@ import io.netty.channel.SimpleChannelInboundHandler
 import io.netty.handler.codec.http.HttpHeaderValues
 import io.netty.handler.codec.http.HttpRequest
 import io.netty.handler.codec.http.HttpResponseStatus
+import io.netty.handler.timeout.IdleStateEvent
 import org.openrs2.buffer.use
 import org.openrs2.game.net.FileProvider
 import javax.inject.Inject
@@ -39,5 +40,21 @@ public class HttpChannelHandler @Inject constructor(
 
     override fun channelReadComplete(ctx: ChannelHandlerContext) {
         ctx.flush()
+
+        if (ctx.channel().isWritable) {
+            ctx.read()
+        }
+    }
+
+    override fun channelWritabilityChanged(ctx: ChannelHandlerContext) {
+        if (ctx.channel().isWritable) {
+            ctx.read()
+        }
+    }
+
+    override fun userEventTriggered(ctx: ChannelHandlerContext, evt: Any) {
+        if (evt is IdleStateEvent) {
+            ctx.close()
+        }
     }
 }

game/src/main/kotlin/org/openrs2/game/net/http/HttpChannelInitializer.kt

@@ -5,6 +5,8 @@ import io.netty.channel.ChannelInitializer
 import io.netty.handler.codec.http.HttpObjectAggregator
 import io.netty.handler.codec.http.HttpRequestDecoder
 import io.netty.handler.codec.http.HttpResponseEncoder
+import io.netty.handler.timeout.IdleStateHandler
+import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -14,6 +16,7 @@ public class HttpChannelInitializer @Inject constructor(
 ) : ChannelInitializer<Channel>() {
     override fun initChannel(ch: Channel) {
         ch.pipeline().addLast(
+            IdleStateHandler(true, Http.TIMEOUT_SECS, Http.TIMEOUT_SECS, Http.TIMEOUT_SECS, TimeUnit.SECONDS),
             HttpRequestDecoder(),
             HttpResponseEncoder(),
             HttpObjectAggregator(Http.MAX_CONTENT_LENGTH),

game/src/main/kotlin/org/openrs2/game/net/login/LoginChannelHandler.kt

@@ -9,6 +9,7 @@ import io.netty.handler.codec.http.HttpObjectAggregator
 import io.netty.handler.codec.http.HttpRequestDecoder
 import io.netty.handler.codec.http.HttpResponseEncoder
 import io.netty.handler.codec.string.StringDecoder
+import io.netty.handler.timeout.IdleStateHandler
 import org.openrs2.buffer.copiedBuffer
 import org.openrs2.game.net.crossdomain.CrossDomainChannelHandler
 import org.openrs2.game.net.http.Http
@@ -22,6 +23,7 @@ import org.openrs2.protocol.js5.Js5ResponseEncoder
 import org.openrs2.protocol.js5.XorDecoder
 import org.openrs2.protocol.login.LoginRequest
 import org.openrs2.protocol.login.LoginResponse
+import java.util.concurrent.TimeUnit
 import javax.inject.Inject
 import javax.inject.Provider
 
@@ -75,6 +77,7 @@ public class LoginChannelHandler @Inject constructor(
 
     private fun handleInitCrossDomainConnection(ctx: ChannelHandlerContext) {
         ctx.pipeline().addLast(
+            IdleStateHandler(true, Http.TIMEOUT_SECS, Http.TIMEOUT_SECS, Http.TIMEOUT_SECS, TimeUnit.SECONDS),
             HttpRequestDecoder(),
             HttpResponseEncoder(),
             HttpObjectAggregator(Http.MAX_CONTENT_LENGTH),