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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  import io.netty.util.internal.UnstableApi;
21  
22  import java.util.Iterator;
23  import java.util.Map.Entry;
24  
25  /**
26   * A collection of headers sent or received via HTTP/2.
27   */
28  @UnstableApi
29  public interface Http2Headers extends Headers<CharSequence, CharSequence, Http2Headers> {
30  
31      /**
32       * HTTP/2 pseudo-headers names.
33       */
34      enum PseudoHeaderName {
35          /**
36           * {@code :method}.
37           */
38          METHOD(":method", true),
39  
40          /**
41           * {@code :scheme}.
42           */
43          SCHEME(":scheme", true),
44  
45          /**
46           * {@code :authority}.
47           */
48          AUTHORITY(":authority", true),
49  
50          /**
51           * {@code :path}.
52           */
53          PATH(":path", true),
54  
55          /**
56           * {@code :status}.
57           */
58          STATUS(":status", false),
59  
60          /**
61           * {@code :protocol}, as defined in <a href="https://datatracker.ietf.org/doc/rfc8441/">RFC 8441,
62           * Bootstrapping WebSockets with HTTP/2</a>.
63           */
64          PROTOCOL(":protocol", true);
65  
66          private static final char PSEUDO_HEADER_PREFIX = ':';
67          private static final byte PSEUDO_HEADER_PREFIX_BYTE = (byte) PSEUDO_HEADER_PREFIX;
68  
69          private final AsciiString value;
70          private final boolean requestOnly;
71  
72          PseudoHeaderName(String value, boolean requestOnly) {
73              this.value = AsciiString.cached(value);
74              this.requestOnly = requestOnly;
75          }
76  
77          public AsciiString value() {
78              // Return a slice so that the buffer gets its own reader index.
79              return value;
80          }
81  
82          /**
83           * Indicates whether the specified header follows the pseudo-header format (begins with ':' character)
84           *
85           * @return {@code true} if the header follow the pseudo-header format
86           */
87          public static boolean hasPseudoHeaderFormat(CharSequence headerName) {
88              if (headerName instanceof AsciiString) {
89                  final AsciiString asciiHeaderName = (AsciiString) headerName;
90                  return asciiHeaderName.length() > 0 && asciiHeaderName.byteAt(0) == PSEUDO_HEADER_PREFIX_BYTE;
91              } else {
92                  return headerName.length() > 0 && headerName.charAt(0) == PSEUDO_HEADER_PREFIX;
93              }
94          }
95  
96          /**
97           * Indicates whether the given header name is a valid HTTP/2 pseudo header.
98           */
99          public static boolean isPseudoHeader(CharSequence header) {
100             return getPseudoHeader(header) != null;
101         }
102 
103         /**
104          * Indicates whether the given header name is a valid HTTP/2 pseudo header.
105          */
106         public static boolean isPseudoHeader(AsciiString header) {
107             return getPseudoHeader(header) != null;
108         }
109 
110         /**
111          * Indicates whether the given header name is a valid HTTP/2 pseudo header.
112          */
113         public static boolean isPseudoHeader(String header) {
114             return getPseudoHeader(header) != null;
115         }
116 
117         /**
118          * Returns the {@link PseudoHeaderName} corresponding to the specified header name.
119          *
120          * @return corresponding {@link PseudoHeaderName} if any, {@code null} otherwise.
121          */
122         public static PseudoHeaderName getPseudoHeader(CharSequence header) {
123             if (header instanceof AsciiString) {
124                 return getPseudoHeader((AsciiString) header);
125             }
126             return getPseudoHeaderName(header);
127         }
128 
129         private static PseudoHeaderName getPseudoHeaderName(CharSequence header) {
130             int length = header.length();
131             if (length > 0 && header.charAt(0) == PSEUDO_HEADER_PREFIX) {
132                 switch (length) {
133                 case 5:
134                     // :path
135                     return ":path".contentEquals(header)? PATH : null;
136                 case 7:
137                     // :method, :scheme, :status
138                     if (":method" == header) {
139                         return METHOD;
140                     }
141                     if (":scheme" == header) {
142                         return SCHEME;
143                     }
144                     if (":status" == header) {
145                         return STATUS;
146                     }
147                     if (":method".contentEquals(header)) {
148                         return METHOD;
149                     }
150                     if (":scheme".contentEquals(header)) {
151                         return SCHEME;
152                     }
153                     return ":status".contentEquals(header)? STATUS : null;
154                 case 9:
155                     // :protocol
156                     return ":protocol".contentEquals(header)? PROTOCOL : null;
157                 case 10:
158                     // :authority
159                     return ":authority".contentEquals(header)? AUTHORITY : null;
160                 }
161             }
162             return null;
163         }
164 
165         /**
166          * Returns the {@link PseudoHeaderName} corresponding to the specified header name.
167          *
168          * @return corresponding {@link PseudoHeaderName} if any, {@code null} otherwise.
169          */
170         public static PseudoHeaderName getPseudoHeader(AsciiString header) {
171             int length = header.length();
172             if (length > 0 && header.charAt(0) == PSEUDO_HEADER_PREFIX) {
173                 switch (length) {
174                 case 5:
175                     // :path
176                     return PATH.value().equals(header) ? PATH : null;
177                 case 7:
178                     if (header == METHOD.value()) {
179                         return METHOD;
180                     }
181                     if (header == SCHEME.value()) {
182                         return SCHEME;
183                     }
184                     if (header == STATUS.value()) {
185                         return STATUS;
186                     }
187                     // :method, :scheme, :status
188                     if (METHOD.value().equals(header)) {
189                         return METHOD;
190                     }
191                     if (SCHEME.value().equals(header)) {
192                         return SCHEME;
193                     }
194                     return STATUS.value().equals(header)? STATUS : null;
195                 case 9:
196                     // :protocol
197                     return PROTOCOL.value().equals(header)? PROTOCOL : null;
198                 case 10:
199                     // :authority
200                     return AUTHORITY.value().equals(header)? AUTHORITY : null;
201                 }
202             }
203             return null;
204         }
205 
206         /**
207          * Indicates whether the pseudo-header is to be used in a request context.
208          *
209          * @return {@code true} if the pseudo-header is to be used in a request context
210          */
211         public boolean isRequestOnly() {
212             return requestOnly;
213         }
214     }
215 
216     /**
217      * Returns an iterator over all HTTP/2 headers. The iteration order is as follows:
218      *   1. All pseudo headers (order not specified).
219      *   2. All non-pseudo headers (in insertion order).
220      */
221     @Override
222     Iterator<Entry<CharSequence, CharSequence>> iterator();
223 
224     /**
225      * Equivalent to {@link #getAll(Object)} but no intermediate list is generated.
226      * @param name the name of the header to retrieve
227      * @return an {@link Iterator} of header values corresponding to {@code name}.
228      */
229     Iterator<CharSequence> valueIterator(CharSequence name);
230 
231     /**
232      * Sets the {@link PseudoHeaderName#METHOD} header
233      */
234     Http2Headers method(CharSequence value);
235 
236     /**
237      * Sets the {@link PseudoHeaderName#SCHEME} header
238      */
239     Http2Headers scheme(CharSequence value);
240 
241     /**
242      * Sets the {@link PseudoHeaderName#AUTHORITY} header
243      */
244     Http2Headers authority(CharSequence value);
245 
246     /**
247      * Sets the {@link PseudoHeaderName#PATH} header
248      */
249     Http2Headers path(CharSequence value);
250 
251     /**
252      * Sets the {@link PseudoHeaderName#STATUS} header
253      */
254     Http2Headers status(CharSequence value);
255 
256     /**
257      * Gets the {@link PseudoHeaderName#METHOD} header or {@code null} if there is no such header
258      */
259     CharSequence method();
260 
261     /**
262      * Gets the {@link PseudoHeaderName#SCHEME} header or {@code null} if there is no such header
263      */
264     CharSequence scheme();
265 
266     /**
267      * Gets the {@link PseudoHeaderName#AUTHORITY} header or {@code null} if there is no such header
268      */
269     CharSequence authority();
270 
271     /**
272      * Gets the {@link PseudoHeaderName#PATH} header or {@code null} if there is no such header
273      */
274     CharSequence path();
275 
276     /**
277      * Gets the {@link PseudoHeaderName#STATUS} header or {@code null} if there is no such header
278      */
279     CharSequence status();
280 
281     /**
282      * Returns {@code true} if a header with the {@code name} and {@code value} exists, {@code false} otherwise.
283      * <p>
284      * If {@code caseInsensitive} is {@code true} then a case insensitive compare is done on the value.
285      *
286      * @param name the name of the header to find
287      * @param value the value of the header to find
288      * @param caseInsensitive {@code true} then a case insensitive compare is run to compare values.
289      * otherwise a case sensitive compare is run to compare values.
290      */
291     boolean contains(CharSequence name, CharSequence value, boolean caseInsensitive);
292 }