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TRAC D.A.P. gateway component, provides authentication, routing, load balancing and API translation
/*
* Copyright 2022 Accenture Global Solutions Limited
*
* Licensed 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 org.finos.tracdap.gateway.proxy.http;
import org.finos.tracdap.common.exception.EUnexpected;
import org.finos.tracdap.config.RouteConfig;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http2.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.annotation.Nonnull;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
public class Http1to2Proxy extends Http2ChannelDuplexHandler {
private final Logger log = LoggerFactory.getLogger(getClass());
private final RouteConfig routeConfig;
private final Map streams;
private final AtomicInteger nextSeqId;
private final int connId;
private int inboundSeqId;
public Http1to2Proxy(RouteConfig routeConfig, int connId) {
this.routeConfig = routeConfig;
this.connId = connId;
this.streams = new HashMap<>();
this.nextSeqId = new AtomicInteger(0);
this.inboundSeqId = -1;
}
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
if (msg instanceof HttpRequest)
newSeqStream(promise);
var frames = translateRequestFrames(msg);
var notLastFrame = frames.subList(0, frames.size() - 1);
var lastFrame = frames.get(frames.size() - 1);
for (var frame : notLastFrame)
ctx.write(frame);
ctx.write(lastFrame, promise);
}
@Override
public void channelRead(@Nonnull ChannelHandlerContext ctx, @Nonnull Object msg) throws Exception {
if (!(msg instanceof Http2Frame))
throw new EUnexpected();
var frame = (Http2Frame) msg;
var httpObjs = translateResponseFrame(frame);
for (var httpObj : httpObjs)
ctx.fireChannelRead(httpObj);
}
private void newSeqStream(ChannelPromise promise) {
inboundSeqId = nextSeqId.getAndIncrement();
var stream = this.newStream();
streams.put(inboundSeqId, stream);
promise.addListener(f -> log.info("conn = {}, seq {} -> stream {}", connId, inboundSeqId, stream.id()));
}
private List translateRequestFrames(Object http1) {
var seqId = inboundSeqId;
var stream = streams.get(seqId);
if (stream == null)
throw new EUnexpected();
var frames = new ArrayList();
if (http1 instanceof HttpRequest) {
var h1Request = (HttpRequest) http1;
var h1Headers = h1Request.headers();
var h2Headers = new DefaultHttp2Headers()
.method(h1Request.method().name())
.scheme(routeConfig.getTarget().getScheme())
.path(h1Request.uri());
if (h1Headers.contains(HttpHeaderNames.HOST))
h2Headers.authority(h1Headers.get(HttpHeaderNames.HOST));
else
h2Headers.authority(routeConfig.getTarget().getHost());
// Copy across all other HTTP/1 headers that we are not explicitly changing or removing
@SuppressWarnings("deprecation") // KEEP_ALIVE is deprecated, but still filter it out
var filterHeaders = List.of(
HttpHeaderNames.HOST.toString(), // Using HTTP/2 :authority
HttpHeaderNames.CONNECTION.toString(), // Not allowed in HTTP/2
HttpHeaderNames.KEEP_ALIVE.toString(), // Not allowed in HTTP/2
HttpHeaderNames.TE.toString()); // Make sure we never send te: trailers
for (var header : h1Headers)
if (!filterHeaders.contains(header.getKey().toLowerCase()))
h2Headers.add(header.getKey().toLowerCase(), header.getValue());
var frame = new DefaultHttp2HeadersFrame(h2Headers, false).stream(stream);
frames.add(frame);
}
if (http1 instanceof HttpContent) {
var h1Content = (HttpContent) http1;
var contentBuf = h1Content.content();
var MAX_DATA_SIZE = 16 * 1024;
contentBuf.retain();
while (contentBuf.readableBytes() > MAX_DATA_SIZE) {
var slice = contentBuf.readSlice(MAX_DATA_SIZE);
var frame = new DefaultHttp2DataFrame(slice).stream(stream);
frames.add(frame);
}
var endStreamFlag = (http1 instanceof LastHttpContent);
var slice = contentBuf.readSlice(contentBuf.readableBytes());
var padding = 256 - (slice.readableBytes() % 256) % 256;
var frame = new DefaultHttp2DataFrame(slice, endStreamFlag, padding).stream(stream);
frames.add(frame);
}
if (frames.isEmpty())
throw new EUnexpected();
return frames;
}
private List translateResponseFrame(Http2Frame frame) {
if (frame instanceof Http2HeadersFrame)
return translateResponseHeaders((Http2HeadersFrame) frame);
if (frame instanceof Http2DataFrame)
return translateResponseData((Http2DataFrame) frame);
throw new EUnexpected();
}
private List translateResponseHeaders(Http2HeadersFrame headersFrame) {
var h2Headers = headersFrame.headers();
var h1Headers = new DefaultHttpHeaders();
for (var header : h2Headers)
if (!header.getKey().toString().startsWith(":"))
h1Headers.add(header.getKey(), header.getValue());
if (!h1Headers.contains(HttpHeaderNames.CONTENT_LENGTH))
h1Headers.add(HttpHeaderNames.TRANSFER_ENCODING, HttpHeaderValues.CHUNKED);
if (h2Headers.contains(":status")) { // regular HTTP/2 headers frame
var statusCode = HttpResponseStatus.parseLine(h2Headers.get(":status"));
var headerObj = new DefaultHttpResponse(HttpVersion.HTTP_1_1, statusCode, h1Headers);
if (headersFrame.isEndStream())
return List.of(headerObj, new DefaultLastHttpContent());
else
return List.of(headerObj);
}
// HTTP/2 trailers frame
else {
// Trailers cannot be converted back to HTTP/1, neither is it safe to discard them
// Since the TE header was removed from the request headers,
// The server should not send a response including trailers
log.error("conn = {}, Unexpected trailers frame in HTTP/2 response", connId);
throw new EUnexpected();
}
}
private List translateResponseData(Http2DataFrame dataFrame) {
dataFrame.content().retain();
if (dataFrame.isEndStream())
return List.of(new DefaultLastHttpContent(dataFrame.content()));
else
return List.of(new DefaultHttpContent(dataFrame.content()));
}
}