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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.handler.codec.Headers;
19  import io.netty.util.AsciiString;
20  
21  import java.util.Iterator;
22  import java.util.Map.Entry;
23  
24  /**
25   * A collection of headers sent or received via HTTP/2.
26   */
27  public interface Http2Headers extends Headers<CharSequence, CharSequence, Http2Headers> {
28  
29      /**
30       * HTTP/2 pseudo-headers names.
31       */
32      enum PseudoHeaderName {
33          /**
34           * {@code :method}.
35           */
36          METHOD(":method", true),
37  
38          /**
39           * {@code :scheme}.
40           */
41          SCHEME(":scheme", true),
42  
43          /**
44           * {@code :authority}.
45           */
46          AUTHORITY(":authority", true),
47  
48          /**
49           * {@code :path}.
50           */
51          PATH(":path", true),
52  
53          /**
54           * {@code :status}.
55           */
56          STATUS(":status", false),
57  
58          /**
59           * {@code :protocol}, as defined in <a href="https://datatracker.ietf.org/doc/rfc8441/">RFC 8441,
60           * Bootstrapping WebSockets with HTTP/2</a>.
61           */
62          PROTOCOL(":protocol", true);
63  
64          private static final char PSEUDO_HEADER_PREFIX = ':';
65          private static final byte PSEUDO_HEADER_PREFIX_BYTE = (byte) PSEUDO_HEADER_PREFIX;
66  
67          private final AsciiString value;
68          private final boolean requestOnly;
69  
70          PseudoHeaderName(String value, boolean requestOnly) {
71              this.value = AsciiString.cached(value);
72              this.requestOnly = requestOnly;
73          }
74  
75          public AsciiString value() {
76              // Return a slice so that the buffer gets its own reader index.
77              return value;
78          }
79  
80          /**
81           * Indicates whether the specified header follows the pseudo-header format (begins with ':' character)
82           *
83           * @return {@code true} if the header follow the pseudo-header format
84           */
85          public static boolean hasPseudoHeaderFormat(CharSequence headerName) {
86              if (headerName instanceof AsciiString) {
87                  final AsciiString asciiHeaderName = (AsciiString) headerName;
88                  return asciiHeaderName.length() > 0 && asciiHeaderName.byteAt(0) == PSEUDO_HEADER_PREFIX_BYTE;
89              } else {
90                  return headerName.length() > 0 && headerName.charAt(0) == PSEUDO_HEADER_PREFIX;
91              }
92          }
93  
94          /**
95           * Indicates whether the given header name is a valid HTTP/2 pseudo header.
96           */
97          public static boolean isPseudoHeader(CharSequence header) {
98              return getPseudoHeader(header) != null;
99          }
100 
101         /**
102          * Indicates whether the given header name is a valid HTTP/2 pseudo header.
103          */
104         public static boolean isPseudoHeader(AsciiString header) {
105             return getPseudoHeader(header) != null;
106         }
107 
108         /**
109          * Indicates whether the given header name is a valid HTTP/2 pseudo header.
110          */
111         public static boolean isPseudoHeader(String header) {
112             return getPseudoHeader(header) != null;
113         }
114 
115         /**
116          * Returns the {@link PseudoHeaderName} corresponding to the specified header name.
117          *
118          * @return corresponding {@link PseudoHeaderName} if any, {@code null} otherwise.
119          */
120         public static PseudoHeaderName getPseudoHeader(CharSequence header) {
121             if (header instanceof AsciiString) {
122                 return getPseudoHeader((AsciiString) header);
123             }
124             return getPseudoHeaderName(header);
125         }
126 
127         private static PseudoHeaderName getPseudoHeaderName(CharSequence header) {
128             int length = header.length();
129             if (length > 0 && header.charAt(0) == PSEUDO_HEADER_PREFIX) {
130                 switch (length) {
131                 case 5:
132                     // :path
133                     return ":path".contentEquals(header)? PATH : null;
134                 case 7:
135                     // :method, :scheme, :status
136                     if (":method" == header) {
137                         return METHOD;
138                     }
139                     if (":scheme" == header) {
140                         return SCHEME;
141                     }
142                     if (":status" == header) {
143                         return STATUS;
144                     }
145                     if (":method".contentEquals(header)) {
146                         return METHOD;
147                     }
148                     if (":scheme".contentEquals(header)) {
149                         return SCHEME;
150                     }
151                     return ":status".contentEquals(header)? STATUS : null;
152                 case 9:
153                     // :protocol
154                     return ":protocol".contentEquals(header)? PROTOCOL : null;
155                 case 10:
156                     // :authority
157                     return ":authority".contentEquals(header)? AUTHORITY : null;
158                 }
159             }
160             return null;
161         }
162 
163         /**
164          * Returns the {@link PseudoHeaderName} corresponding to the specified header name.
165          *
166          * @return corresponding {@link PseudoHeaderName} if any, {@code null} otherwise.
167          */
168         public static PseudoHeaderName getPseudoHeader(AsciiString header) {
169             int length = header.length();
170             if (length > 0 && header.charAt(0) == PSEUDO_HEADER_PREFIX) {
171                 switch (length) {
172                 case 5:
173                     // :path
174                     return PATH.value().equals(header) ? PATH : null;
175                 case 7:
176                     if (header == METHOD.value()) {
177                         return METHOD;
178                     }
179                     if (header == SCHEME.value()) {
180                         return SCHEME;
181                     }
182                     if (header == STATUS.value()) {
183                         return STATUS;
184                     }
185                     // :method, :scheme, :status
186                     if (METHOD.value().equals(header)) {
187                         return METHOD;
188                     }
189                     if (SCHEME.value().equals(header)) {
190                         return SCHEME;
191                     }
192                     return STATUS.value().equals(header)? STATUS : null;
193                 case 9:
194                     // :protocol
195                     return PROTOCOL.value().equals(header)? PROTOCOL : null;
196                 case 10:
197                     // :authority
198                     return AUTHORITY.value().equals(header)? AUTHORITY : null;
199                 }
200             }
201             return null;
202         }
203 
204         /**
205          * Indicates whether the pseudo-header is to be used in a request context.
206          *
207          * @return {@code true} if the pseudo-header is to be used in a request context
208          */
209         public boolean isRequestOnly() {
210             return requestOnly;
211         }
212     }
213 
214     /**
215      * Returns an iterator over all HTTP/2 headers. The iteration order is as follows:
216      *   1. All pseudo headers (order not specified).
217      *   2. All non-pseudo headers (in insertion order).
218      */
219     @Override
220     Iterator<Entry<CharSequence, CharSequence>> iterator();
221 
222     /**
223      * Equivalent to {@link #getAll(Object)} but no intermediate list is generated.
224      * @param name the name of the header to retrieve
225      * @return an {@link Iterator} of header values corresponding to {@code name}.
226      */
227     Iterator<CharSequence> valueIterator(CharSequence name);
228 
229     /**
230      * Sets the {@link PseudoHeaderName#METHOD} header
231      */
232     Http2Headers method(CharSequence value);
233 
234     /**
235      * Sets the {@link PseudoHeaderName#SCHEME} header
236      */
237     Http2Headers scheme(CharSequence value);
238 
239     /**
240      * Sets the {@link PseudoHeaderName#AUTHORITY} header
241      */
242     Http2Headers authority(CharSequence value);
243 
244     /**
245      * Sets the {@link PseudoHeaderName#PATH} header
246      */
247     Http2Headers path(CharSequence value);
248 
249     /**
250      * Sets the {@link PseudoHeaderName#STATUS} header
251      */
252     Http2Headers status(CharSequence value);
253 
254     /**
255      * Gets the {@link PseudoHeaderName#METHOD} header or {@code null} if there is no such header
256      */
257     CharSequence method();
258 
259     /**
260      * Gets the {@link PseudoHeaderName#SCHEME} header or {@code null} if there is no such header
261      */
262     CharSequence scheme();
263 
264     /**
265      * Gets the {@link PseudoHeaderName#AUTHORITY} header or {@code null} if there is no such header
266      */
267     CharSequence authority();
268 
269     /**
270      * Gets the {@link PseudoHeaderName#PATH} header or {@code null} if there is no such header
271      */
272     CharSequence path();
273 
274     /**
275      * Gets the {@link PseudoHeaderName#STATUS} header or {@code null} if there is no such header
276      */
277     CharSequence status();
278 
279     /**
280      * Returns {@code true} if a header with the {@code name} and {@code value} exists, {@code false} otherwise.
281      * <p>
282      * If {@code caseInsensitive} is {@code true} then a case insensitive compare is done on the value.
283      *
284      * @param name the name of the header to find
285      * @param value the value of the header to find
286      * @param caseInsensitive {@code true} then a case insensitive compare is run to compare values.
287      * otherwise a case sensitive compare is run to compare values.
288      */
289     boolean contains(CharSequence name, CharSequence value, boolean caseInsensitive);
290 }