1 /*
2 * Copyright 2014 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
5 * "License"); you may not use this file except in compliance with the License. You may obtain a
6 * copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software distributed under the License
11 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12 * or implied. See the License for the specific language governing permissions and limitations under
13 * the License.
14 */
15
16 package io.netty.handler.codec.http2;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.util.internal.UnstableApi;
20
21 /**
22 * Decodes HPACK-encoded headers blocks into {@link Http2Headers}.
23 */
24 @UnstableApi
25 public interface Http2HeadersDecoder {
26 /**
27 * Configuration related elements for the {@link Http2HeadersDecoder} interface
28 */
29 interface Configuration {
30 /**
31 * Represents the value for
32 * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_HEADER_TABLE_SIZE</a>.
33 * This method should only be called by Netty (not users) as a result of a receiving a {@code SETTINGS} frame.
34 */
35 void maxHeaderTableSize(long max) throws Http2Exception;
36
37 /**
38 * Represents the value for
39 * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_HEADER_TABLE_SIZE</a>. The initial value
40 * returned by this method must be {@link Http2CodecUtil#DEFAULT_HEADER_TABLE_SIZE}.
41 */
42 long maxHeaderTableSize();
43
44 /**
45 * Configure the maximum allowed size in bytes of each set of headers.
46 * <p>
47 * This method should only be called by Netty (not users) as a result of a receiving a {@code SETTINGS} frame.
48 * @param max <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a>.
49 * If this limit is exceeded the implementation should attempt to keep the HPACK header tables up to date
50 * by processing data from the peer, but a {@code RST_STREAM} frame will be sent for the offending stream.
51 * @param goAwayMax Must be {@code >= max}. A {@code GO_AWAY} frame will be generated if this limit is exceeded
52 * for any particular stream.
53 * @throws Http2Exception if limits exceed the RFC's boundaries or {@code max > goAwayMax}.
54 */
55 void maxHeaderListSize(long max, long goAwayMax) throws Http2Exception;
56
57 /**
58 * Represents the value for
59 * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a>.
60 */
61 long maxHeaderListSize();
62
63 /**
64 * Represents the upper bound in bytes for a set of headers before a {@code GO_AWAY} should be sent.
65 * This will be {@code <=}
66 * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a>.
67 */
68 long maxHeaderListSizeGoAway();
69 }
70
71 /**
72 * Decodes the given headers block and returns the headers.
73 */
74 Http2Headers decodeHeaders(int streamId, ByteBuf headerBlock) throws Http2Exception;
75
76 /**
77 * Get the {@link Configuration} for this {@link Http2HeadersDecoder}
78 */
79 Configuration configuration();
80 }