/*
* Copyright 2016 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.handler.codec.http2;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageCodec;
import io.netty.handler.codec.http.DefaultHttpContent;
import io.netty.handler.codec.http.DefaultLastHttpContent;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.HttpContent;
import io.netty.handler.codec.http.HttpHeaderNames;
import io.netty.handler.codec.http.HttpHeaderValues;
import io.netty.handler.codec.http.HttpObject;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpUtil;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.LastHttpContent;
import io.netty.util.ReferenceCountUtil;
import io.netty.util.internal.UnstableApi;
import java.util.List;
/**
* This is a server-side adapter so that an http2 codec can be downgraded to
* appear as if it's speaking http/1.1.
*
* In particular, this handler converts from {@link Http2StreamFrame} to {@link
* HttpObject}, and back. For simplicity, it converts to chunked encoding
* unless the entire stream is a single header.
*/
@UnstableApi
public class Http2ServerDowngrader extends MessageToMessageCodec<Http2StreamFrame, HttpObject> {
private final boolean validateHeaders;
public Http2ServerDowngrader(boolean validateHeaders) {
this.validateHeaders = validateHeaders;
}
public Http2ServerDowngrader() {
this(true);
}
@Override
public boolean acceptInboundMessage(Object msg) throws Exception {
return (msg instanceof Http2HeadersFrame) || (msg instanceof Http2DataFrame);
}
@Override
protected void decode(ChannelHandlerContext ctx, Http2StreamFrame frame, List<Object> out) throws Exception {
if (frame instanceof Http2HeadersFrame) {
int id = 0; // not really the id
Http2HeadersFrame headersFrame = (Http2HeadersFrame) frame;
Http2Headers headers = headersFrame.headers();
if (headersFrame.isEndStream()) {
if (headers.method() == null) {
LastHttpContent last = new DefaultLastHttpContent(Unpooled.EMPTY_BUFFER, validateHeaders);
HttpConversionUtil.addHttp2ToHttpHeaders(id, headers, last.trailingHeaders(),
HttpVersion.HTTP_1_1, true, true);
out.add(last);
} else {
FullHttpRequest full = HttpConversionUtil.toFullHttpRequest(id, headers, ctx.alloc(),
validateHeaders);
out.add(full);
}
} else {
HttpRequest req = HttpConversionUtil.toHttpRequest(id, headersFrame.headers(), validateHeaders);
if (!HttpUtil.isContentLengthSet(req)) {
req.headers().add(HttpHeaderNames.TRANSFER_ENCODING, HttpHeaderValues.CHUNKED);
}
out.add(req);
}
} else if (frame instanceof Http2DataFrame) {
Http2DataFrame dataFrame = (Http2DataFrame) frame;
if (dataFrame.isEndStream()) {
out.add(new DefaultLastHttpContent(dataFrame.content(), validateHeaders));
} else {
out.add(new DefaultHttpContent(dataFrame.content()));
}
}
ReferenceCountUtil.retain(frame);
}
private void encodeLastContent(LastHttpContent last, List<Object> out) {
boolean needFiller = !(last instanceof FullHttpResponse) && last.trailingHeaders().isEmpty();
if (last.content().isReadable() || needFiller) {
out.add(new DefaultHttp2DataFrame(last.content(), last.trailingHeaders().isEmpty()));
}
if (!last.trailingHeaders().isEmpty()) {
Http2Headers headers = HttpConversionUtil.toHttp2Headers(last.trailingHeaders(), validateHeaders);
out.add(new DefaultHttp2HeadersFrame(headers, true));
}
}
@Override
protected void encode(ChannelHandlerContext ctx, HttpObject obj, List<Object> out) throws Exception {
if (obj instanceof HttpResponse) {
Http2Headers headers = HttpConversionUtil.toHttp2Headers((HttpResponse) obj, validateHeaders);
boolean noMoreFrames = false;
if (obj instanceof FullHttpResponse) {
FullHttpResponse full = (FullHttpResponse) obj;
noMoreFrames = !full.content().isReadable() && full.trailingHeaders().isEmpty();
}
out.add(new DefaultHttp2HeadersFrame(headers, noMoreFrames));
}
if (obj instanceof LastHttpContent) {
LastHttpContent last = (LastHttpContent) obj;
encodeLastContent(last, out);
} else if (obj instanceof HttpContent) {
HttpContent cont = (HttpContent) obj;
out.add(new DefaultHttp2DataFrame(cont.content(), false));
}
ReferenceCountUtil.retain(obj);
}
}