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io.netty5.handler.codec.http.HttpObjectEncoder Maven / Gradle / Ivy
/*
* Copyright 2012 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:
*
* https://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.netty5.handler.codec.http;
import io.netty5.buffer.Buffer;
import io.netty5.buffer.BufferAllocator;
import io.netty5.channel.ChannelHandlerContext;
import io.netty5.channel.FileRegion;
import io.netty5.handler.codec.MessageToMessageEncoder;
import io.netty5.handler.codec.http.headers.HttpHeaders;
import io.netty5.util.Resource;
import io.netty5.util.internal.StringUtil;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map.Entry;
import java.util.function.Supplier;
import static io.netty5.handler.codec.http.HttpConstants.CR;
import static io.netty5.handler.codec.http.HttpConstants.LF;
/**
* Encodes an {@link HttpMessage} or an {@link HttpContent} into
* a {@link Buffer}.
*
* Extensibility
*
* Please note that this encoder is designed to be extended to implement
* a protocol derived from HTTP, such as
* RTSP and
* ICAP .
* To implement the encoder of such a derived protocol, extend this class and
* implement all abstract methods properly.
*/
public abstract class HttpObjectEncoder extends MessageToMessageEncoder {
static final short CRLF_SHORT = (CR << 8) | LF;
private static final int ZERO_CRLF_MEDIUM = ('0' << 16) | CRLF_SHORT;
private static final byte[] CRLF = {CR, LF};
private static final byte[] ZERO_CRLF_CRLF = { '0', CR, LF, CR, LF };
private static final float HEADERS_WEIGHT_NEW = 1 / 5f;
private static final float HEADERS_WEIGHT_HISTORICAL = 1 - HEADERS_WEIGHT_NEW;
private static final float TRAILERS_WEIGHT_NEW = HEADERS_WEIGHT_NEW;
private static final float TRAILERS_WEIGHT_HISTORICAL = HEADERS_WEIGHT_HISTORICAL;
private static final int ST_INIT = 0;
private static final int ST_CONTENT_NON_CHUNK = 1;
private static final int ST_CONTENT_CHUNK = 2;
private static final int ST_CONTENT_ALWAYS_EMPTY = 3;
private Supplier crlfBufferSupplier;
private Supplier zeroCrlfCrlfBufferSupplier;
@SuppressWarnings("RedundantFieldInitialization")
private int state = ST_INIT;
/**
* Used to calculate an exponential moving average of the encoded size of the initial line and the headers for
* a guess for future buffer allocations.
*/
private float headersEncodedSizeAccumulator = 256;
/**
* Used to calculate an exponential moving average of the encoded size of the trailers for
* a guess for future buffer allocations.
*/
private float trailersEncodedSizeAccumulator = 256;
@Override
protected void encodeAndClose(ChannelHandlerContext ctx, Object msg, List out) throws Exception {
Buffer buf = null;
if (msg instanceof HttpMessage) {
if (state != ST_INIT) {
throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg)
+ ", state: " + state);
}
@SuppressWarnings({ "unchecked", "CastConflictsWithInstanceof" })
H m = (H) msg;
buf = ctx.bufferAllocator().allocate((int) headersEncodedSizeAccumulator);
// Encode the message.
encodeInitialLine(buf, m);
state = isContentAlwaysEmpty(m) ? ST_CONTENT_ALWAYS_EMPTY :
HttpUtil.isTransferEncodingChunked(m) ? ST_CONTENT_CHUNK : ST_CONTENT_NON_CHUNK;
sanitizeHeadersBeforeEncode(m, state == ST_CONTENT_ALWAYS_EMPTY);
encodeHeaders(m.headers(), buf);
buf.writeShort(CRLF_SHORT);
headersEncodedSizeAccumulator = HEADERS_WEIGHT_NEW * padSizeForAccumulation(buf.readableBytes()) +
HEADERS_WEIGHT_HISTORICAL * headersEncodedSizeAccumulator;
}
// Bypass the encoder in case of an empty buffer, so that the following idiom works:
//
// ch.write(ctx.bufferAllocator().allocate(0)).addListener(ch, ChannelFutureListeners.CLOSE);
//
// See https://github.com/netty/netty/issues/2983 for more information.
if (msg instanceof Buffer && ((Buffer) msg).readableBytes() == 0) {
out.add(msg);
return;
}
if (msg instanceof HttpContent || msg instanceof Buffer || msg instanceof FileRegion) {
switch (state) {
case ST_INIT:
Resource.dispose(msg);
throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg)
+ ", state: " + state);
case ST_CONTENT_NON_CHUNK:
final long contentLength = contentLength(msg);
if (contentLength > 0) {
if (buf != null && buf.writableBytes() >= contentLength && msg instanceof HttpContent) {
// merge into other buffer for performance reasons
buf.writeBytes(((HttpContent) msg).payload());
Resource.dispose(msg);
out.add(buf);
} else {
if (buf != null) {
out.add(buf);
}
out.add(encode(msg));
}
if (msg instanceof LastHttpContent) {
state = ST_INIT;
}
break;
} else {
// do not break, let's fall-through
}
// fall-through!
case ST_CONTENT_ALWAYS_EMPTY:
Resource.dispose(msg);
if (buf != null) {
// We allocated a buffer so add it now.
out.add(buf);
} else {
// Need to produce some output otherwise an IllegalStateException will be thrown as we did not
// write anything. Writing an empty buffer will not actually write anything on the wire, so if
// there is a user error with msg it will not be visible externally
out.add(ctx.bufferAllocator().allocate(0));
}
break;
case ST_CONTENT_CHUNK:
if (buf != null) {
// We allocated a buffer so add it now.
out.add(buf);
}
encodeChunkedContent(ctx, msg, contentLength(msg), out);
break;
default:
throw new Error();
}
if (msg instanceof LastHttpContent) {
state = ST_INIT;
}
} else if (buf != null) {
out.add(buf);
}
}
/**
* Encode the {@link HttpHeaders} into a {@link Buffer}.
*/
protected void encodeHeaders(HttpHeaders headers, Buffer buf) {
for (Entry header : headers) {
HttpHeadersEncoder.encoderHeader(header.getKey(), header.getValue(), buf);
}
}
private void encodeChunkedContent(ChannelHandlerContext ctx, Object msg, long contentLength, List out) {
if (contentLength > 0) {
String lengthHex = Long.toHexString(contentLength);
Buffer buf = ctx.bufferAllocator().allocate(lengthHex.length() + 2);
buf.writeCharSequence(lengthHex, StandardCharsets.US_ASCII);
buf.writeShort(CRLF_SHORT);
out.add(buf);
out.add(encode(msg));
out.add(crlfBuffer(ctx.bufferAllocator()));
}
if (msg instanceof LastHttpContent) {
HttpHeaders headers = ((LastHttpContent) msg).trailingHeaders();
if (headers.isEmpty()) {
out.add(zeroCrlfCrlfBuffer(ctx.bufferAllocator()));
} else {
Buffer buf = ctx.bufferAllocator().allocate((int) trailersEncodedSizeAccumulator);
buf.writeMedium(ZERO_CRLF_MEDIUM);
encodeHeaders(headers, buf);
buf.writeShort(CRLF_SHORT);
trailersEncodedSizeAccumulator = TRAILERS_WEIGHT_NEW * padSizeForAccumulation(buf.readableBytes()) +
TRAILERS_WEIGHT_HISTORICAL * trailersEncodedSizeAccumulator;
out.add(buf);
}
if (contentLength == 0) {
// EmptyLastHttpContent or LastHttpContent with empty payload
((LastHttpContent) msg).close();
}
} else if (contentLength == 0) {
// Need to produce some output otherwise an
// IllegalStateException will be thrown
out.add(encode(msg));
}
}
/**
* Allows to sanitize headers of the message before encoding these.
*/
protected void sanitizeHeadersBeforeEncode(@SuppressWarnings("unused") H msg, boolean isAlwaysEmpty) {
// noop
}
/**
* Determine whether a message has a content or not. Some message may have headers indicating
* a content without having an actual content, e.g the response to an HEAD or CONNECT request.
*
* @param msg the message to test
* @return {@code true} to signal the message has no content
*/
protected boolean isContentAlwaysEmpty(@SuppressWarnings("unused") H msg) {
return false;
}
@Override
public boolean acceptOutboundMessage(Object msg) throws Exception {
return msg instanceof HttpObject || msg instanceof Buffer || msg instanceof FileRegion;
}
private static Object encode(Object msg) {
if (msg instanceof Buffer) {
return msg;
}
if (msg instanceof HttpContent) {
return ((HttpContent) msg).payload();
}
if (msg instanceof FileRegion) {
return msg;
}
Resource.dispose(msg);
throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg));
}
private static long contentLength(Object msg) {
if (msg instanceof HttpContent) {
return ((HttpContent) msg).payload().readableBytes();
}
if (msg instanceof Buffer) {
return ((Buffer) msg).readableBytes();
}
if (msg instanceof FileRegion) {
return ((FileRegion) msg).count();
}
Resource.dispose(msg);
throw new IllegalStateException("unexpected message type: " + StringUtil.simpleClassName(msg));
}
/**
* Add some additional overhead to the buffer. The rational is that it is better to slightly over allocate and waste
* some memory, rather than under allocate and require a resize/copy.
* @param readableBytes The readable bytes in the buffer.
* @return The {@code readableBytes} with some additional padding.
*/
private static int padSizeForAccumulation(int readableBytes) {
return (readableBytes << 2) / 3;
}
protected abstract void encodeInitialLine(Buffer buf, H message) throws Exception;
protected Buffer crlfBuffer(BufferAllocator allocator) {
if (crlfBufferSupplier == null) {
crlfBufferSupplier = allocator.constBufferSupplier(CRLF);
}
return crlfBufferSupplier.get();
}
protected Buffer zeroCrlfCrlfBuffer(BufferAllocator allocator) {
if (zeroCrlfCrlfBufferSupplier == null) {
zeroCrlfCrlfBufferSupplier = allocator.constBufferSupplier(ZERO_CRLF_CRLF);
}
return zeroCrlfCrlfBufferSupplier.get();
}
}
