package com.typesafe.netty.http;
import com.typesafe.netty.CancelledSubscriber;
import com.typesafe.netty.HandlerPublisher;
import com.typesafe.netty.HandlerSubscriber;
import io.netty.channel.*;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker;
import io.netty.handler.codec.http.websocketx.WebSocketVersion;
import org.reactivestreams.Publisher;
import java.util.Collections;
import java.util.List;
import java.util.NoSuchElementException;
/**
* Handler that reads {@link HttpRequest} messages followed by {@link HttpContent} messages and produces
* {@link StreamedHttpRequest} messages, and converts written {@link StreamedHttpResponse} messages into
* {@link HttpResponse} messages followed by {@link HttpContent} messages.
*
* This allows request and response bodies to be handled using reactive streams.
*
* There are two types of messages that this handler will send down the chain, {@link StreamedHttpRequest},
* and {@link FullHttpRequest}. If {@link io.netty.channel.ChannelOption#AUTO_READ} is false for the channel,
* then any {@link StreamedHttpRequest} messages <em>must</em> be subscribed to consume the body, otherwise
* it's possible that no read will be done of the messages.
*
* There are three types of messages that this handler accepts for writing, {@link StreamedHttpResponse},
* {@link WebSocketHttpResponse} and {@link FullHttpResponse}. Writing any other messages may potentially
* lead to HTTP message mangling.
*
* As long as messages are returned in the order that they arrive, this handler implicitly supports HTTP
* pipelining.
*/
public class HttpStreamsServerHandler extends HttpStreamsHandler<HttpRequest, HttpResponse> {
private HttpRequest lastRequest = null;
private Outgoing webSocketResponse = null;
private int inFlight = 0;
private boolean continueExpected = true;
private boolean sendContinue = false;
private boolean close = false;
private final List<ChannelHandler> dependentHandlers;
public HttpStreamsServerHandler() {
this(Collections.<ChannelHandler>emptyList());
}
/**
* Create a new handler that is depended on by the given handlers.
*
* The list of dependent handlers will be removed from the chain when this handler is removed from the chain,
* for example, when the connection is upgraded to use websockets. This is useful, for example, for removing
* the reactive streams publisher/subscriber from the chain in that event.
*
* @param dependentHandlers The handlers that depend on this handler.
*/
public HttpStreamsServerHandler(List<ChannelHandler> dependentHandlers) {
super(HttpRequest.class, HttpResponse.class);
this.dependentHandlers = dependentHandlers;
}
@Override
protected boolean hasBody(HttpRequest request) {
// Http requests don't have a body if they define 0 content length, or no content length and no transfer
// encoding
return HttpUtil.getContentLength(request, 0) != 0 || HttpUtil.isTransferEncodingChunked(request);
}
@Override
protected HttpRequest createEmptyMessage(HttpRequest request) {
return new EmptyHttpRequest(request);
}
@Override
protected HttpRequest createStreamedMessage(HttpRequest httpRequest, Publisher<HttpContent> stream) {
return new DelegateStreamedHttpRequest(httpRequest, stream);
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
// Set to false, since if it was true, and the client is sending data, then the
// client must no longer be expecting it (due to a timeout, for example).
continueExpected = false;
sendContinue = false;
if (msg instanceof HttpRequest) {
HttpRequest request = (HttpRequest) msg;
lastRequest = request;
if (HttpUtil.is100ContinueExpected(request)) {
continueExpected = true;
}
}
super.channelRead(ctx, msg);
}
@Override
protected void receivedInMessage(ChannelHandlerContext ctx) {
inFlight++;
}
@Override
protected void sentOutMessage(ChannelHandlerContext ctx) {
inFlight--;
if (inFlight == 1 && continueExpected && sendContinue) {
ctx.writeAndFlush(new DefaultFullHttpResponse(lastRequest.protocolVersion(), HttpResponseStatus.CONTINUE));
sendContinue = false;
continueExpected = false;
}
if (close) {
ctx.close();
}
}
@Override
protected void unbufferedWrite(ChannelHandlerContext ctx, HttpStreamsHandler<HttpRequest, HttpResponse>.Outgoing out) {
if (out.message instanceof WebSocketHttpResponse) {
if ((lastRequest instanceof FullHttpRequest) || !hasBody(lastRequest)) {
handleWebSocketResponse(ctx, out);
} else {
// If the response has a streamed body, then we can't send the WebSocket response until we've received
// the body.
webSocketResponse = out;
}
} else {
String connection = out.message.headers().get(HttpHeaderNames.CONNECTION);
if (lastRequest.protocolVersion().isKeepAliveDefault()) {
if ("close".equalsIgnoreCase(connection)) {
close = true;
}
} else {
if (!"keep-alive".equalsIgnoreCase(connection)) {
close = true;
}
}
if (inFlight == 1 && continueExpected) {
HttpUtil.setKeepAlive(out.message, false);
close = true;
continueExpected = false;
}
// According to RFC 7230 a server MUST NOT send a Content-Length or a Transfer-Encoding when the status
// code is 1xx or 204, also a status code 304 may not have a Content-Length or Transfer-Encoding set.
if (!HttpUtil.isContentLengthSet(out.message) && !HttpUtil.isTransferEncodingChunked(out.message)
&& canHaveBody(out.message)) {
HttpUtil.setKeepAlive(out.message, false);
close = true;
}
super.unbufferedWrite(ctx, out);
}
}
private boolean canHaveBody(HttpResponse message) {
HttpResponseStatus status = message.status();
// All 1xx (Informational), 204 (No Content), and 304 (Not Modified)
// responses do not include a message body
return !(status == HttpResponseStatus.CONTINUE || status == HttpResponseStatus.SWITCHING_PROTOCOLS ||
status == HttpResponseStatus.PROCESSING || status == HttpResponseStatus.NO_CONTENT ||
status == HttpResponseStatus.NOT_MODIFIED);
}
@Override
protected void consumedInMessage(ChannelHandlerContext ctx) {
if (webSocketResponse != null) {
handleWebSocketResponse(ctx, webSocketResponse);
webSocketResponse = null;
}
}
private void handleWebSocketResponse(ChannelHandlerContext ctx, Outgoing out) {
WebSocketHttpResponse response = (WebSocketHttpResponse) out.message;
WebSocketServerHandshaker handshaker = response.handshakerFactory().newHandshaker(lastRequest);
if (handshaker == null) {
HttpResponse res = new DefaultFullHttpResponse(
HttpVersion.HTTP_1_1,
HttpResponseStatus.UPGRADE_REQUIRED);
res.headers().set(HttpHeaderNames.SEC_WEBSOCKET_VERSION, WebSocketVersion.V13.toHttpHeaderValue());
HttpUtil.setContentLength(res, 0);
super.unbufferedWrite(ctx, new Outgoing(res, out.promise));
response.subscribe(new CancelledSubscriber<>());
} else {
// First, insert new handlers in the chain after us for handling the websocket
ChannelPipeline pipeline = ctx.pipeline();
HandlerPublisher<WebSocketFrame> publisher = new HandlerPublisher<>(ctx.executor(), WebSocketFrame.class);
HandlerSubscriber<WebSocketFrame> subscriber = new HandlerSubscriber<>(ctx.executor());
pipeline.addAfter(ctx.executor(), ctx.name(), "websocket-subscriber", subscriber);
pipeline.addAfter(ctx.executor(), ctx.name(), "websocket-publisher", publisher);
// Now remove ourselves from the chain
ctx.pipeline().remove(ctx.name());
// Now do the handshake
// Wrap the request in an empty request because we don't need the WebSocket handshaker ignoring the body,
// we already have handled the body.
handshaker.handshake(ctx.channel(), new EmptyHttpRequest(lastRequest));
// And hook up the subscriber/publishers
response.subscribe(subscriber);
publisher.subscribe(response);
}
}
@Override
protected void bodyRequested(ChannelHandlerContext ctx) {
if (continueExpected) {
if (inFlight == 1) {
ctx.writeAndFlush(new DefaultFullHttpResponse(lastRequest.protocolVersion(), HttpResponseStatus.CONTINUE));
continueExpected = false;
} else {
sendContinue = true;
}
}
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
super.handlerRemoved(ctx);
for (ChannelHandler dependent: dependentHandlers) {
try {
ctx.pipeline().remove(dependent);
} catch (NoSuchElementException e) {
// Ignore, maybe something else removed it
}
}
}
}
