/*
* Copyright 2015 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.handler.codec.http2.Http2HeadersEncoder.SensitivityDetector;
import io.netty.util.internal.UnstableApi;
import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_MAX_RESERVED_STREAMS;
import static io.netty.util.internal.ObjectUtil.checkNotNull;
import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;
/**
* Abstract base class which defines commonly used features required to build {@link Http2ConnectionHandler} instances.
*
* <h3>Three ways to build a {@link Http2ConnectionHandler}</h3>
* <h4>Let the builder create a {@link Http2ConnectionHandler}</h4>
* Simply call all the necessary setter methods, and then use {@link #build()} to build a new
* {@link Http2ConnectionHandler}. Setting the following properties are prohibited because they are used for
* other ways of building a {@link Http2ConnectionHandler}.
* conflicts with this option:
* <ul>
* <li>{@link #connection(Http2Connection)}</li>
* <li>{@link #codec(Http2ConnectionDecoder, Http2ConnectionEncoder)}</li>
* </ul>
*
*
* <h4>Let the builder use the {@link Http2ConnectionHandler} you specified</h4>
* Call {@link #connection(Http2Connection)} to tell the builder that you want to build the handler from the
* {@link Http2Connection} you specified. Setting the following properties are prohibited and thus will trigger
* an {@link IllegalStateException} because they conflict with this option.
* <ul>
* <li>{@link #server(boolean)}</li>
* <li>{@link #codec(Http2ConnectionDecoder, Http2ConnectionEncoder)}</li>
* </ul>
*
* <h4>Let the builder use the {@link Http2ConnectionDecoder} and {@link Http2ConnectionEncoder} you specified</h4>
* Call {@link #codec(Http2ConnectionDecoder, Http2ConnectionEncoder)} to tell the builder that you want to built the
* handler from the {@link Http2ConnectionDecoder} and {@link Http2ConnectionEncoder} you specified. Setting the
* following properties are prohibited and thus will trigger an {@link IllegalStateException} because they conflict
* with this option:
* <ul>
* <li>{@link #server(boolean)}</li>
* <li>{@link #connection(Http2Connection)}</li>
* <li>{@link #frameLogger(Http2FrameLogger)}</li>
* <li>{@link #headerSensitivityDetector(SensitivityDetector)}</li>
* <li>{@link #encoderEnforceMaxConcurrentStreams(boolean)}</li>
* <li>{@link #encoderIgnoreMaxHeaderListSize(boolean)}</li>
* </ul>
*
* <h3>Exposing necessary methods in a subclass</h3>
* {@link #build()} method and all property access methods are {@code protected}. Choose the methods to expose to the
* users of your builder implementation and make them {@code public}.
*
* @param <T> The type of handler created by this builder.
* @param <B> The concrete type of this builder.
*/
@UnstableApi
public abstract class AbstractHttp2ConnectionHandlerBuilder<T extends Http2ConnectionHandler,
B extends AbstractHttp2ConnectionHandlerBuilder<T, B>> {
private static final long DEFAULT_GRACEFUL_SHUTDOWN_TIMEOUT_MILLIS = MILLISECONDS.convert(30, SECONDS);
private static final SensitivityDetector DEFAULT_HEADER_SENSITIVITY_DETECTOR = Http2HeadersEncoder.NEVER_SENSITIVE;
// The properties that can always be set.
private Http2Settings initialSettings = Http2Settings.defaultSettings();
private Http2FrameListener frameListener;
private long gracefulShutdownTimeoutMillis = DEFAULT_GRACEFUL_SHUTDOWN_TIMEOUT_MILLIS;
// The property that will prohibit connection() and codec() if set by server(),
// because this property is used only when this builder creates a Http2Connection.
private Boolean isServer;
private Integer maxReservedStreams;
// The property that will prohibit server() and codec() if set by connection().
private Http2Connection connection;
// The properties that will prohibit server() and connection() if set by codec().
private Http2ConnectionDecoder decoder;
private Http2ConnectionEncoder encoder;
// The properties that are:
// * mutually exclusive against codec() and
// * OK to use with server() and connection()
private Boolean validateHeaders;
private Http2FrameLogger frameLogger;
private SensitivityDetector headerSensitivityDetector;
private Boolean encoderEnforceMaxConcurrentStreams;
private Boolean encoderIgnoreMaxHeaderListSize;
/**
* Sets the {@link Http2Settings} to use for the initial connection settings exchange.
*/
protected Http2Settings initialSettings() {
return initialSettings;
}
/**
* Sets the {@link Http2Settings} to use for the initial connection settings exchange.
*/
protected B initialSettings(Http2Settings settings) {
initialSettings = checkNotNull(settings, "settings");
return self();
}
/**
* Returns the listener of inbound frames.
*
* @return {@link Http2FrameListener} if set, or {@code null} if not set.
*/
protected Http2FrameListener frameListener() {
return frameListener;
}
/**
* Sets the listener of inbound frames.
* This listener will only be set if the decoder's listener is {@code null}.
*/
protected B frameListener(Http2FrameListener frameListener) {
this.frameListener = checkNotNull(frameListener, "frameListener");
return self();
}
/**
* Returns the graceful shutdown timeout of the {@link Http2Connection} in milliseconds.
*/
protected long gracefulShutdownTimeoutMillis() {
return gracefulShutdownTimeoutMillis;
}
/**
* Sets the graceful shutdown timeout of the {@link Http2Connection} in milliseconds.
*/
protected B gracefulShutdownTimeoutMillis(long gracefulShutdownTimeoutMillis) {
this.gracefulShutdownTimeoutMillis = gracefulShutdownTimeoutMillis;
return self();
}
/**
* Returns if {@link #build()} will to create a {@link Http2Connection} in server mode ({@code true})
* or client mode ({@code false}).
*/
protected boolean isServer() {
return isServer != null ? isServer : true;
}
/**
* Sets if {@link #build()} will to create a {@link Http2Connection} in server mode ({@code true})
* or client mode ({@code false}).
*/
protected B server(boolean isServer) {
enforceConstraint("server", "connection", connection);
enforceConstraint("server", "codec", decoder);
enforceConstraint("server", "codec", encoder);
this.isServer = isServer;
return self();
}
/**
* Get the maximum number of streams which can be in the reserved state at any given time.
* <p>
* By default this value will be ignored on the server for local endpoint. This is because the RFC provides
* no way to explicitly communicate a limit to how many states can be in the reserved state, and instead relies
* on the peer to send RST_STREAM frames when they will be rejected.
*/
protected int maxReservedStreams() {
return maxReservedStreams != null ? maxReservedStreams : DEFAULT_MAX_RESERVED_STREAMS;
}
/**
* Set the maximum number of streams which can be in the reserved state at any given time.
*/
protected B maxReservedStreams(int maxReservedStreams) {
enforceConstraint("server", "connection", connection);
enforceConstraint("server", "codec", decoder);
enforceConstraint("server", "codec", encoder);
this.maxReservedStreams = checkPositiveOrZero(maxReservedStreams, "maxReservedStreams");
return self();
}
/**
* Returns the {@link Http2Connection} to use.
*
* @return {@link Http2Connection} if set, or {@code null} if not set.
*/
protected Http2Connection connection() {
return connection;
}
/**
* Sets the {@link Http2Connection} to use.
*/
protected B connection(Http2Connection connection) {
enforceConstraint("connection", "maxReservedStreams", maxReservedStreams);
enforceConstraint("connection", "server", isServer);
enforceConstraint("connection", "codec", decoder);
enforceConstraint("connection", "codec", encoder);
this.connection = checkNotNull(connection, "connection");
return self();
}
/**
* Returns the {@link Http2ConnectionDecoder} to use.
*
* @return {@link Http2ConnectionDecoder} if set, or {@code null} if not set.
*/
protected Http2ConnectionDecoder decoder() {
return decoder;
}
/**
* Returns the {@link Http2ConnectionEncoder} to use.
*
* @return {@link Http2ConnectionEncoder} if set, or {@code null} if not set.
*/
protected Http2ConnectionEncoder encoder() {
return encoder;
}
/**
* Sets the {@link Http2ConnectionDecoder} and {@link Http2ConnectionEncoder} to use.
*/
protected B codec(Http2ConnectionDecoder decoder, Http2ConnectionEncoder encoder) {
enforceConstraint("codec", "server", isServer);
enforceConstraint("codec", "maxReservedStreams", maxReservedStreams);
enforceConstraint("codec", "connection", connection);
enforceConstraint("codec", "frameLogger", frameLogger);
enforceConstraint("codec", "validateHeaders", validateHeaders);
enforceConstraint("codec", "headerSensitivityDetector", headerSensitivityDetector);
enforceConstraint("codec", "encoderEnforceMaxConcurrentStreams", encoderEnforceMaxConcurrentStreams);
checkNotNull(decoder, "decoder");
checkNotNull(encoder, "encoder");
if (decoder.connection() != encoder.connection()) {
throw new IllegalArgumentException("The specified encoder and decoder have different connections.");
}
this.decoder = decoder;
this.encoder = encoder;
return self();
}
/**
* Returns if HTTP headers should be validated according to
* <a href="https://tools.ietf.org/html/rfc7540#section-8.1.2.6">RFC 7540, 8.1.2.6</a>.
*/
protected boolean isValidateHeaders() {
return validateHeaders != null ? validateHeaders : true;
}
/**
* Sets if HTTP headers should be validated according to
* <a href="https://tools.ietf.org/html/rfc7540#section-8.1.2.6">RFC 7540, 8.1.2.6</a>.
*/
protected B validateHeaders(boolean validateHeaders) {
enforceNonCodecConstraints("validateHeaders");
this.validateHeaders = validateHeaders;
return self();
}
/**
* Returns the logger that is used for the encoder and decoder.
*
* @return {@link Http2FrameLogger} if set, or {@code null} if not set.
*/
protected Http2FrameLogger frameLogger() {
return frameLogger;
}
/**
* Sets the logger that is used for the encoder and decoder.
*/
protected B frameLogger(Http2FrameLogger frameLogger) {
enforceNonCodecConstraints("frameLogger");
this.frameLogger = checkNotNull(frameLogger, "frameLogger");
return self();
}
/**
* Returns if the encoder should queue frames if the maximum number of concurrent streams
* would otherwise be exceeded.
*/
protected boolean encoderEnforceMaxConcurrentStreams() {
return encoderEnforceMaxConcurrentStreams != null ? encoderEnforceMaxConcurrentStreams : false;
}
/**
* Sets if the encoder should queue frames if the maximum number of concurrent streams
* would otherwise be exceeded.
*/
protected B encoderEnforceMaxConcurrentStreams(boolean encoderEnforceMaxConcurrentStreams) {
enforceNonCodecConstraints("encoderEnforceMaxConcurrentStreams");
this.encoderEnforceMaxConcurrentStreams = encoderEnforceMaxConcurrentStreams;
return self();
}
/**
* Returns the {@link SensitivityDetector} to use.
*/
protected SensitivityDetector headerSensitivityDetector() {
return headerSensitivityDetector != null ? headerSensitivityDetector : DEFAULT_HEADER_SENSITIVITY_DETECTOR;
}
/**
* Sets the {@link SensitivityDetector} to use.
*/
protected B headerSensitivityDetector(SensitivityDetector headerSensitivityDetector) {
enforceNonCodecConstraints("headerSensitivityDetector");
this.headerSensitivityDetector = checkNotNull(headerSensitivityDetector, "headerSensitivityDetector");
return self();
}
/**
* Sets if the <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a>
* should be ignored when encoding headers.
* @param ignoreMaxHeaderListSize {@code true} to ignore
* <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a>.
* @return this.
*/
protected B encoderIgnoreMaxHeaderListSize(boolean ignoreMaxHeaderListSize) {
enforceNonCodecConstraints("encoderIgnoreMaxHeaderListSize");
this.encoderIgnoreMaxHeaderListSize = ignoreMaxHeaderListSize;
return self();
}
/**
* Create a new {@link Http2ConnectionHandler}.
*/
protected T build() {
if (encoder != null) {
assert decoder != null;
return buildFromCodec(decoder, encoder);
}
Http2Connection connection = this.connection;
if (connection == null) {
connection = new DefaultHttp2Connection(isServer(), maxReservedStreams());
}
return buildFromConnection(connection);
}
private T buildFromConnection(Http2Connection connection) {
Long maxHeaderListSize = initialSettings.maxHeaderListSize();
Http2FrameReader reader = new DefaultHttp2FrameReader(maxHeaderListSize == null ?
new DefaultHttp2HeadersDecoder(isValidateHeaders()) :
new DefaultHttp2HeadersDecoder(isValidateHeaders(), maxHeaderListSize));
Http2FrameWriter writer = encoderIgnoreMaxHeaderListSize == null ?
new DefaultHttp2FrameWriter(headerSensitivityDetector()) :
new DefaultHttp2FrameWriter(headerSensitivityDetector(), encoderIgnoreMaxHeaderListSize);
if (frameLogger != null) {
reader = new Http2InboundFrameLogger(reader, frameLogger);
writer = new Http2OutboundFrameLogger(writer, frameLogger);
}
Http2ConnectionEncoder encoder = new DefaultHttp2ConnectionEncoder(connection, writer);
boolean encoderEnforceMaxConcurrentStreams = encoderEnforceMaxConcurrentStreams();
if (encoderEnforceMaxConcurrentStreams) {
if (connection.isServer()) {
encoder.close();
reader.close();
throw new IllegalArgumentException(
"encoderEnforceMaxConcurrentStreams: " + encoderEnforceMaxConcurrentStreams +
" not supported for server");
}
encoder = new StreamBufferingEncoder(encoder);
}
Http2ConnectionDecoder decoder = new DefaultHttp2ConnectionDecoder(connection, encoder, reader);
return buildFromCodec(decoder, encoder);
}
private T buildFromCodec(Http2ConnectionDecoder decoder, Http2ConnectionEncoder encoder) {
final T handler;
try {
// Call the abstract build method
handler = build(decoder, encoder, initialSettings);
} catch (Throwable t) {
encoder.close();
decoder.close();
throw new IllegalStateException("failed to build a Http2ConnectionHandler", t);
}
// Setup post build options
handler.gracefulShutdownTimeoutMillis(gracefulShutdownTimeoutMillis);
if (handler.decoder().frameListener() == null) {
handler.decoder().frameListener(frameListener);
}
return handler;
}
/**
* Implement this method to create a new {@link Http2ConnectionHandler} or its subtype instance.
* <p>
* The return of this method will be subject to the following:
* <ul>
* <li>{@link #frameListener(Http2FrameListener)} will be set if not already set in the decoder</li>
* <li>{@link #gracefulShutdownTimeoutMillis(long)} will always be set</li>
* </ul>
*/
protected abstract T build(Http2ConnectionDecoder decoder, Http2ConnectionEncoder encoder,
Http2Settings initialSettings) throws Exception;
/**
* Returns {@code this}.
*/
@SuppressWarnings("unchecked")
protected final B self() {
return (B) this;
}
private void enforceNonCodecConstraints(String rejected) {
enforceConstraint(rejected, "server/connection", decoder);
enforceConstraint(rejected, "server/connection", encoder);
}
private static void enforceConstraint(String methodName, String rejectorName, Object value) {
if (value != null) {
throw new IllegalStateException(
methodName + "() cannot be called because " + rejectorName + "() has been called already.");
}
}
}