io.netty.handler.codec.http2.DefaultHttp2HeadersDecoder Maven / Gradle / Ivy
/*
* Copyright 2014 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.netty.handler.codec.http2;
import io.netty.buffer.ByteBuf;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.UnstableApi;
import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_HEADER_LIST_SIZE;
import static io.netty.handler.codec.http2.Http2Error.COMPRESSION_ERROR;
import static io.netty.handler.codec.http2.Http2Error.INTERNAL_ERROR;
import static io.netty.handler.codec.http2.Http2Exception.connectionError;
@UnstableApi
public class DefaultHttp2HeadersDecoder implements Http2HeadersDecoder, Http2HeadersDecoder.Configuration {
private static final float HEADERS_COUNT_WEIGHT_NEW = 1 / 5f;
private static final float HEADERS_COUNT_WEIGHT_HISTORICAL = 1 - HEADERS_COUNT_WEIGHT_NEW;
private final HpackDecoder hpackDecoder;
private final boolean validateHeaders;
private final boolean validateHeaderValues;
private long maxHeaderListSizeGoAway;
/**
* Used to calculate an exponential moving average of header sizes to get an estimate of how large the data
* structure for storing headers should be.
*/
private float headerArraySizeAccumulator = 8;
public DefaultHttp2HeadersDecoder() {
this(true);
}
/**
* Create a new instance.
* @param validateHeaders {@code true} to validate headers are valid according to the RFC.
*/
public DefaultHttp2HeadersDecoder(boolean validateHeaders) {
this(validateHeaders, DEFAULT_HEADER_LIST_SIZE);
}
/**
* Create a new instance.
*
* @param validateHeaders {@code true} to validate headers are valid according to the RFC.
* This validates everything except header values.
* @param validateHeaderValues {@code true} to validate that header values are valid according to the RFC.
* Since this is potentially expensive, it can be enabled separately from {@code validateHeaders}.
*/
public DefaultHttp2HeadersDecoder(boolean validateHeaders, boolean validateHeaderValues) {
this(validateHeaders, validateHeaderValues, DEFAULT_HEADER_LIST_SIZE);
}
/**
* Create a new instance.
* @param validateHeaders {@code true} to validate headers are valid according to the RFC.
* @param maxHeaderListSize This is the only setting that can be configured before notifying the peer.
* This is because SETTINGS_MAX_HEADER_LIST_SIZE
* allows a lower than advertised limit from being enforced, and the default limit is unlimited
* (which is dangerous).
*/
public DefaultHttp2HeadersDecoder(boolean validateHeaders, long maxHeaderListSize) {
this(validateHeaders, false, new HpackDecoder(maxHeaderListSize));
}
/**
* Create a new instance.
* @param validateHeaders {@code true} to validate headers are valid according to the RFC.
* This validates everything except header values.
* @param validateHeaderValues {@code true} to validate that header values are valid according to the RFC.
* Since this is potentially expensive, it can be enabled separately from {@code validateHeaders}.
* @param maxHeaderListSize This is the only setting that can be configured before notifying the peer.
* This is because SETTINGS_MAX_HEADER_LIST_SIZE
* allows a lower than advertised limit from being enforced, and the default limit is unlimited
* (which is dangerous).
*/
public DefaultHttp2HeadersDecoder(boolean validateHeaders, boolean validateHeaderValues, long maxHeaderListSize) {
this(validateHeaders, validateHeaderValues, new HpackDecoder(maxHeaderListSize));
}
/**
* Create a new instance.
* @param validateHeaders {@code true} to validate headers are valid according to the RFC.
* This validates everything except header values.
* @param maxHeaderListSize This is the only setting that can be configured before notifying the peer.
* This is because SETTINGS_MAX_HEADER_LIST_SIZE
* allows a lower than advertised limit from being enforced, and the default limit is unlimited
* (which is dangerous).
* @param initialHuffmanDecodeCapacity Does nothing, do not use.
*/
public DefaultHttp2HeadersDecoder(boolean validateHeaders, long maxHeaderListSize,
@Deprecated int initialHuffmanDecodeCapacity) {
this(validateHeaders, false, new HpackDecoder(maxHeaderListSize));
}
/**
* Exposed for testing only! Default values used in the initial settings frame are overridden intentionally
* for testing but violate the RFC if used outside the scope of testing.
*/
DefaultHttp2HeadersDecoder(boolean validateHeaders, boolean validateHeaderValues, HpackDecoder hpackDecoder) {
this.hpackDecoder = ObjectUtil.checkNotNull(hpackDecoder, "hpackDecoder");
this.validateHeaders = validateHeaders;
this.validateHeaderValues = validateHeaderValues;
maxHeaderListSizeGoAway =
Http2CodecUtil.calculateMaxHeaderListSizeGoAway(hpackDecoder.getMaxHeaderListSize());
}
@Override
public void maxHeaderTableSize(long max) throws Http2Exception {
hpackDecoder.setMaxHeaderTableSize(max);
}
@Override
public long maxHeaderTableSize() {
return hpackDecoder.getMaxHeaderTableSize();
}
@Override
public void maxHeaderListSize(long max, long goAwayMax) throws Http2Exception {
if (goAwayMax < max || goAwayMax < 0) {
throw connectionError(INTERNAL_ERROR, "Header List Size GO_AWAY %d must be non-negative and >= %d",
goAwayMax, max);
}
hpackDecoder.setMaxHeaderListSize(max);
maxHeaderListSizeGoAway = goAwayMax;
}
@Override
public long maxHeaderListSize() {
return hpackDecoder.getMaxHeaderListSize();
}
@Override
public long maxHeaderListSizeGoAway() {
return maxHeaderListSizeGoAway;
}
@Override
public Configuration configuration() {
return this;
}
@Override
public Http2Headers decodeHeaders(int streamId, ByteBuf headerBlock) throws Http2Exception {
try {
final Http2Headers headers = newHeaders();
hpackDecoder.decode(streamId, headerBlock, headers, validateHeaders);
headerArraySizeAccumulator = HEADERS_COUNT_WEIGHT_NEW * headers.size() +
HEADERS_COUNT_WEIGHT_HISTORICAL * headerArraySizeAccumulator;
return headers;
} catch (Http2Exception e) {
throw e;
} catch (Throwable e) {
// Default handler for any other types of errors that may have occurred. For example,
// the Header builder throws IllegalArgumentException if the key or value was invalid
// for any reason (e.g. the key was an invalid pseudo-header).
throw connectionError(COMPRESSION_ERROR, e, "Error decoding headers: %s", e.getMessage());
}
}
/**
* A weighted moving average estimating how many headers are expected during the decode process.
* @return an estimate of how many headers are expected during the decode process.
*/
protected final int numberOfHeadersGuess() {
return (int) headerArraySizeAccumulator;
}
/**
* Determines if the headers should be validated as a result of the decode operation.
*
* Note: This does not include validation of header values, since that is potentially
* expensive to do. Value validation is instead {@linkplain #validateHeaderValues() enabled separately}.
*
* @return {@code true} if the headers should be validated as a result of the decode operation.
*/
protected final boolean validateHeaders() {
return validateHeaders;
}
/**
* Determines if the header values should be validated as a result of the decode operation.
*
* Note: This only validates the values of headers. All other header validations are
* instead {@linkplain #validateHeaders() enabled separately}.
*
* @return {@code true} if the header values should be validated as a result of the decode operation.
*/
protected boolean validateHeaderValues() { // Not 'final' due to backwards compatibility.
return validateHeaderValues;
}
/**
* Create a new {@link Http2Headers} object which will store the results of the decode operation.
* @return a new {@link Http2Headers} object which will store the results of the decode operation.
*/
protected Http2Headers newHeaders() {
return new DefaultHttp2Headers(validateHeaders, validateHeaderValues, (int) headerArraySizeAccumulator);
}
}