001/*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.net;
016
017import com.google.common.annotations.Beta;
018import com.google.common.annotations.GwtCompatible;
019
020/**
021 * Contains constant definitions for the HTTP header field names. See:
022 *
023 * <ul>
024 *   <li><a href="http://www.ietf.org/rfc/rfc2109.txt">RFC 2109</a>
025 *   <li><a href="http://www.ietf.org/rfc/rfc2183.txt">RFC 2183</a>
026 *   <li><a href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a>
027 *   <li><a href="http://www.ietf.org/rfc/rfc2965.txt">RFC 2965</a>
028 *   <li><a href="http://www.ietf.org/rfc/rfc5988.txt">RFC 5988</a>
029 * </ul>
030 *
031 *
032 * @author Kurt Alfred Kluever
033 * @since 11.0
034 */
035@GwtCompatible
036public final class HttpHeaders {
037  private HttpHeaders() {}
038
039  // HTTP Request and Response header fields
040
041  /** The HTTP {@code Cache-Control} header field name. */
042  public static final String CACHE_CONTROL = "Cache-Control";
043  /** The HTTP {@code Content-Length} header field name. */
044  public static final String CONTENT_LENGTH = "Content-Length";
045  /** The HTTP {@code Content-Type} header field name. */
046  public static final String CONTENT_TYPE = "Content-Type";
047  /** The HTTP {@code Date} header field name. */
048  public static final String DATE = "Date";
049  /** The HTTP {@code Pragma} header field name. */
050  public static final String PRAGMA = "Pragma";
051  /** The HTTP {@code Via} header field name. */
052  public static final String VIA = "Via";
053  /** The HTTP {@code Warning} header field name. */
054  public static final String WARNING = "Warning";
055
056  // HTTP Request header fields
057
058  /** The HTTP {@code Accept} header field name. */
059  public static final String ACCEPT = "Accept";
060  /** The HTTP {@code Accept-Charset} header field name. */
061  public static final String ACCEPT_CHARSET = "Accept-Charset";
062  /** The HTTP {@code Accept-Encoding} header field name. */
063  public static final String ACCEPT_ENCODING = "Accept-Encoding";
064  /** The HTTP {@code Accept-Language} header field name. */
065  public static final String ACCEPT_LANGUAGE = "Accept-Language";
066  /** The HTTP {@code Access-Control-Request-Headers} header field name. */
067  public static final String ACCESS_CONTROL_REQUEST_HEADERS = "Access-Control-Request-Headers";
068  /** The HTTP {@code Access-Control-Request-Method} header field name. */
069  public static final String ACCESS_CONTROL_REQUEST_METHOD = "Access-Control-Request-Method";
070  /** The HTTP {@code Authorization} header field name. */
071  public static final String AUTHORIZATION = "Authorization";
072  /** The HTTP {@code Connection} header field name. */
073  public static final String CONNECTION = "Connection";
074  /** The HTTP {@code Cookie} header field name. */
075  public static final String COOKIE = "Cookie";
076  /**
077   * The HTTP <a href="https://fetch.spec.whatwg.org/#cross-origin-resource-policy-header">{@code
078   * Cross-Origin-Resource-Policy}</a> header field name.
079   *
080   * @since 28.0
081   */
082  public static final String CROSS_ORIGIN_RESOURCE_POLICY = "Cross-Origin-Resource-Policy";
083  /**
084   * The HTTP <a href="https://tools.ietf.org/html/rfc8470">{@code Early-Data}</a> header field
085   * name.
086   *
087   * @since 27.0
088   */
089  public static final String EARLY_DATA = "Early-Data";
090  /** The HTTP {@code Expect} header field name. */
091  public static final String EXPECT = "Expect";
092  /** The HTTP {@code From} header field name. */
093  public static final String FROM = "From";
094  /**
095   * The HTTP <a href="https://tools.ietf.org/html/rfc7239">{@code Forwarded}</a> header field name.
096   *
097   * @since 20.0
098   */
099  public static final String FORWARDED = "Forwarded";
100  /**
101   * The HTTP {@code Follow-Only-When-Prerender-Shown} header field name.
102   *
103   * @since 17.0
104   */
105  @Beta
106  public static final String FOLLOW_ONLY_WHEN_PRERENDER_SHOWN = "Follow-Only-When-Prerender-Shown";
107  /** The HTTP {@code Host} header field name. */
108  public static final String HOST = "Host";
109  /**
110   * The HTTP <a href="https://tools.ietf.org/html/rfc7540#section-3.2.1">{@code HTTP2-Settings}
111   * </a> header field name.
112   *
113   * @since 24.0
114   */
115  public static final String HTTP2_SETTINGS = "HTTP2-Settings";
116  /** The HTTP {@code If-Match} header field name. */
117  public static final String IF_MATCH = "If-Match";
118  /** The HTTP {@code If-Modified-Since} header field name. */
119  public static final String IF_MODIFIED_SINCE = "If-Modified-Since";
120  /** The HTTP {@code If-None-Match} header field name. */
121  public static final String IF_NONE_MATCH = "If-None-Match";
122  /** The HTTP {@code If-Range} header field name. */
123  public static final String IF_RANGE = "If-Range";
124  /** The HTTP {@code If-Unmodified-Since} header field name. */
125  public static final String IF_UNMODIFIED_SINCE = "If-Unmodified-Since";
126  /** The HTTP {@code Last-Event-ID} header field name. */
127  public static final String LAST_EVENT_ID = "Last-Event-ID";
128  /** The HTTP {@code Max-Forwards} header field name. */
129  public static final String MAX_FORWARDS = "Max-Forwards";
130  /** The HTTP {@code Origin} header field name. */
131  public static final String ORIGIN = "Origin";
132  /** The HTTP {@code Proxy-Authorization} header field name. */
133  public static final String PROXY_AUTHORIZATION = "Proxy-Authorization";
134  /** The HTTP {@code Range} header field name. */
135  public static final String RANGE = "Range";
136  /** The HTTP {@code Referer} header field name. */
137  public static final String REFERER = "Referer";
138  /**
139   * The HTTP <a href="https://www.w3.org/TR/referrer-policy/">{@code Referrer-Policy}</a> header
140   * field name.
141   *
142   * @since 23.4
143   */
144  public static final String REFERRER_POLICY = "Referrer-Policy";
145
146  /**
147   * Values for the <a href="https://www.w3.org/TR/referrer-policy/">{@code Referrer-Policy}</a>
148   * header.
149   *
150   * @since 23.4
151   */
152  public static final class ReferrerPolicyValues {
153    private ReferrerPolicyValues() {}
154
155    public static final String NO_REFERRER = "no-referrer";
156    public static final String NO_REFFERER_WHEN_DOWNGRADE = "no-referrer-when-downgrade";
157    public static final String SAME_ORIGIN = "same-origin";
158    public static final String ORIGIN = "origin";
159    public static final String STRICT_ORIGIN = "strict-origin";
160    public static final String ORIGIN_WHEN_CROSS_ORIGIN = "origin-when-cross-origin";
161    public static final String STRICT_ORIGIN_WHEN_CROSS_ORIGIN = "strict-origin-when-cross-origin";
162    public static final String UNSAFE_URL = "unsafe-url";
163  }
164
165  /**
166   * The HTTP <a href="https://www.w3.org/TR/service-workers/#update-algorithm">{@code
167   * Service-Worker}</a> header field name.
168   */
169  public static final String SERVICE_WORKER = "Service-Worker";
170  /** The HTTP {@code TE} header field name. */
171  public static final String TE = "TE";
172  /** The HTTP {@code Upgrade} header field name. */
173  public static final String UPGRADE = "Upgrade";
174  /**
175   * The HTTP <a href="https://w3c.github.io/webappsec-upgrade-insecure-requests/#preference">{@code
176   * Upgrade-Insecure-Requests}</a> header field name.
177   *
178   * @since 28.1
179   */
180  public static final String UPGRADE_INSECURE_REQUESTS = "Upgrade-Insecure-Requests";
181
182  /** The HTTP {@code User-Agent} header field name. */
183  public static final String USER_AGENT = "User-Agent";
184
185  // HTTP Response header fields
186
187  /** The HTTP {@code Accept-Ranges} header field name. */
188  public static final String ACCEPT_RANGES = "Accept-Ranges";
189  /** The HTTP {@code Access-Control-Allow-Headers} header field name. */
190  public static final String ACCESS_CONTROL_ALLOW_HEADERS = "Access-Control-Allow-Headers";
191  /** The HTTP {@code Access-Control-Allow-Methods} header field name. */
192  public static final String ACCESS_CONTROL_ALLOW_METHODS = "Access-Control-Allow-Methods";
193  /** The HTTP {@code Access-Control-Allow-Origin} header field name. */
194  public static final String ACCESS_CONTROL_ALLOW_ORIGIN = "Access-Control-Allow-Origin";
195  /** The HTTP {@code Access-Control-Allow-Credentials} header field name. */
196  public static final String ACCESS_CONTROL_ALLOW_CREDENTIALS = "Access-Control-Allow-Credentials";
197  /** The HTTP {@code Access-Control-Expose-Headers} header field name. */
198  public static final String ACCESS_CONTROL_EXPOSE_HEADERS = "Access-Control-Expose-Headers";
199  /** The HTTP {@code Access-Control-Max-Age} header field name. */
200  public static final String ACCESS_CONTROL_MAX_AGE = "Access-Control-Max-Age";
201  /** The HTTP {@code Age} header field name. */
202  public static final String AGE = "Age";
203  /** The HTTP {@code Allow} header field name. */
204  public static final String ALLOW = "Allow";
205  /** The HTTP {@code Content-Disposition} header field name. */
206  public static final String CONTENT_DISPOSITION = "Content-Disposition";
207  /** The HTTP {@code Content-Encoding} header field name. */
208  public static final String CONTENT_ENCODING = "Content-Encoding";
209  /** The HTTP {@code Content-Language} header field name. */
210  public static final String CONTENT_LANGUAGE = "Content-Language";
211  /** The HTTP {@code Content-Location} header field name. */
212  public static final String CONTENT_LOCATION = "Content-Location";
213  /** The HTTP {@code Content-MD5} header field name. */
214  public static final String CONTENT_MD5 = "Content-MD5";
215  /** The HTTP {@code Content-Range} header field name. */
216  public static final String CONTENT_RANGE = "Content-Range";
217  /**
218   * The HTTP <a href="http://w3.org/TR/CSP/#content-security-policy-header-field">{@code
219   * Content-Security-Policy}</a> header field name.
220   *
221   * @since 15.0
222   */
223  public static final String CONTENT_SECURITY_POLICY = "Content-Security-Policy";
224  /**
225   * The HTTP <a href="http://w3.org/TR/CSP/#content-security-policy-report-only-header-field">
226   * {@code Content-Security-Policy-Report-Only}</a> header field name.
227   *
228   * @since 15.0
229   */
230  public static final String CONTENT_SECURITY_POLICY_REPORT_ONLY =
231      "Content-Security-Policy-Report-Only";
232  /**
233   * The HTTP nonstandard {@code X-Content-Security-Policy} header field name. It was introduced in
234   * <a href="https://www.w3.org/TR/2011/WD-CSP-20111129/">CSP v.1</a> and used by the Firefox until
235   * version 23 and the Internet Explorer version 10. Please, use {@link #CONTENT_SECURITY_POLICY}
236   * to pass the CSP.
237   *
238   * @since 20.0
239   */
240  public static final String X_CONTENT_SECURITY_POLICY = "X-Content-Security-Policy";
241  /**
242   * The HTTP nonstandard {@code X-Content-Security-Policy-Report-Only} header field name. It was
243   * introduced in <a href="https://www.w3.org/TR/2011/WD-CSP-20111129/">CSP v.1</a> and used by the
244   * Firefox until version 23 and the Internet Explorer version 10. Please, use {@link
245   * #CONTENT_SECURITY_POLICY_REPORT_ONLY} to pass the CSP.
246   *
247   * @since 20.0
248   */
249  public static final String X_CONTENT_SECURITY_POLICY_REPORT_ONLY =
250      "X-Content-Security-Policy-Report-Only";
251  /**
252   * The HTTP nonstandard {@code X-WebKit-CSP} header field name. It was introduced in <a
253   * href="https://www.w3.org/TR/2011/WD-CSP-20111129/">CSP v.1</a> and used by the Chrome until
254   * version 25. Please, use {@link #CONTENT_SECURITY_POLICY} to pass the CSP.
255   *
256   * @since 20.0
257   */
258  public static final String X_WEBKIT_CSP = "X-WebKit-CSP";
259  /**
260   * The HTTP nonstandard {@code X-WebKit-CSP-Report-Only} header field name. It was introduced in
261   * <a href="https://www.w3.org/TR/2011/WD-CSP-20111129/">CSP v.1</a> and used by the Chrome until
262   * version 25. Please, use {@link #CONTENT_SECURITY_POLICY_REPORT_ONLY} to pass the CSP.
263   *
264   * @since 20.0
265   */
266  public static final String X_WEBKIT_CSP_REPORT_ONLY = "X-WebKit-CSP-Report-Only";
267  /** The HTTP {@code ETag} header field name. */
268  public static final String ETAG = "ETag";
269  /** The HTTP {@code Expires} header field name. */
270  public static final String EXPIRES = "Expires";
271  /** The HTTP {@code Last-Modified} header field name. */
272  public static final String LAST_MODIFIED = "Last-Modified";
273  /** The HTTP {@code Link} header field name. */
274  public static final String LINK = "Link";
275  /** The HTTP {@code Location} header field name. */
276  public static final String LOCATION = "Location";
277  /**
278   * The HTTP <a href="https://googlechrome.github.io/OriginTrials/#header">{@code Origin-Trial}</a>
279   * header field name.
280   *
281   * @since 27.1
282   */
283  public static final String ORIGIN_TRIAL = "Origin-Trial";
284  /** The HTTP {@code P3P} header field name. Limited browser support. */
285  public static final String P3P = "P3P";
286  /** The HTTP {@code Proxy-Authenticate} header field name. */
287  public static final String PROXY_AUTHENTICATE = "Proxy-Authenticate";
288  /** The HTTP {@code Refresh} header field name. Non-standard header supported by most browsers. */
289  public static final String REFRESH = "Refresh";
290  /**
291   * The HTTP <a href="https://www.w3.org/TR/reporting/">{@code Report-To}</a> header field name.
292   *
293   * @since 27.1
294   */
295  public static final String REPORT_TO = "Report-To";
296  /** The HTTP {@code Retry-After} header field name. */
297  public static final String RETRY_AFTER = "Retry-After";
298  /** The HTTP {@code Server} header field name. */
299  public static final String SERVER = "Server";
300  /**
301   * The HTTP <a href="https://www.w3.org/TR/server-timing/">{@code Server-Timing}</a> header field
302   * name.
303   *
304   * @since 23.6
305   */
306  public static final String SERVER_TIMING = "Server-Timing";
307  /**
308   * The HTTP <a href="https://www.w3.org/TR/service-workers/#update-algorithm">{@code
309   * Service-Worker-Allowed}</a> header field name.
310   *
311   * @since 20.0
312   */
313  public static final String SERVICE_WORKER_ALLOWED = "Service-Worker-Allowed";
314  /** The HTTP {@code Set-Cookie} header field name. */
315  public static final String SET_COOKIE = "Set-Cookie";
316  /** The HTTP {@code Set-Cookie2} header field name. */
317  public static final String SET_COOKIE2 = "Set-Cookie2";
318
319  /**
320   * The HTTP <a href="http://goo.gl/Dxx19N">{@code SourceMap}</a> header field name.
321   *
322   * @since 27.1
323   */
324  @Beta public static final String SOURCE_MAP = "SourceMap";
325
326  /**
327   * The HTTP <a href="http://tools.ietf.org/html/rfc6797#section-6.1">{@code
328   * Strict-Transport-Security}</a> header field name.
329   *
330   * @since 15.0
331   */
332  public static final String STRICT_TRANSPORT_SECURITY = "Strict-Transport-Security";
333  /**
334   * The HTTP <a href="http://www.w3.org/TR/resource-timing/#cross-origin-resources">{@code
335   * Timing-Allow-Origin}</a> header field name.
336   *
337   * @since 15.0
338   */
339  public static final String TIMING_ALLOW_ORIGIN = "Timing-Allow-Origin";
340  /** The HTTP {@code Trailer} header field name. */
341  public static final String TRAILER = "Trailer";
342  /** The HTTP {@code Transfer-Encoding} header field name. */
343  public static final String TRANSFER_ENCODING = "Transfer-Encoding";
344  /** The HTTP {@code Vary} header field name. */
345  public static final String VARY = "Vary";
346  /** The HTTP {@code WWW-Authenticate} header field name. */
347  public static final String WWW_AUTHENTICATE = "WWW-Authenticate";
348
349  // Common, non-standard HTTP header fields
350
351  /** The HTTP {@code DNT} header field name. */
352  public static final String DNT = "DNT";
353  /** The HTTP {@code X-Content-Type-Options} header field name. */
354  public static final String X_CONTENT_TYPE_OPTIONS = "X-Content-Type-Options";
355  /** The HTTP {@code X-Do-Not-Track} header field name. */
356  public static final String X_DO_NOT_TRACK = "X-Do-Not-Track";
357  /** The HTTP {@code X-Forwarded-For} header field name (superseded by {@code Forwarded}). */
358  public static final String X_FORWARDED_FOR = "X-Forwarded-For";
359  /** The HTTP {@code X-Forwarded-Proto} header field name. */
360  public static final String X_FORWARDED_PROTO = "X-Forwarded-Proto";
361  /**
362   * The HTTP <a href="http://goo.gl/lQirAH">{@code X-Forwarded-Host}</a> header field name.
363   *
364   * @since 20.0
365   */
366  public static final String X_FORWARDED_HOST = "X-Forwarded-Host";
367  /**
368   * The HTTP <a href="http://goo.gl/YtV2at">{@code X-Forwarded-Port}</a> header field name.
369   *
370   * @since 20.0
371   */
372  public static final String X_FORWARDED_PORT = "X-Forwarded-Port";
373  /** The HTTP {@code X-Frame-Options} header field name. */
374  public static final String X_FRAME_OPTIONS = "X-Frame-Options";
375  /** The HTTP {@code X-Powered-By} header field name. */
376  public static final String X_POWERED_BY = "X-Powered-By";
377  /**
378   * The HTTP <a href="http://tools.ietf.org/html/draft-evans-palmer-key-pinning">{@code
379   * Public-Key-Pins}</a> header field name.
380   *
381   * @since 15.0
382   */
383  @Beta public static final String PUBLIC_KEY_PINS = "Public-Key-Pins";
384  /**
385   * The HTTP <a href="http://tools.ietf.org/html/draft-evans-palmer-key-pinning">{@code
386   * Public-Key-Pins-Report-Only}</a> header field name.
387   *
388   * @since 15.0
389   */
390  @Beta public static final String PUBLIC_KEY_PINS_REPORT_ONLY = "Public-Key-Pins-Report-Only";
391  /** The HTTP {@code X-Requested-With} header field name. */
392  public static final String X_REQUESTED_WITH = "X-Requested-With";
393  /** The HTTP {@code X-User-IP} header field name. */
394  public static final String X_USER_IP = "X-User-IP";
395  /**
396   * The HTTP <a href="https://goo.gl/VKpXxa">{@code X-Download-Options}</a> header field name.
397   *
398   * <p>When the new X-Download-Options header is present with the value {@code noopen}, the user is
399   * prevented from opening a file download directly; instead, they must first save the file
400   * locally.
401   *
402   * @since 24.1
403   */
404  @Beta public static final String X_DOWNLOAD_OPTIONS = "X-Download-Options";
405  /** The HTTP {@code X-XSS-Protection} header field name. */
406  public static final String X_XSS_PROTECTION = "X-XSS-Protection";
407  /**
408   * The HTTP <a
409   * href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-DNS-Prefetch-Control">{@code
410   * X-DNS-Prefetch-Control}</a> header controls DNS prefetch behavior. Value can be "on" or "off".
411   * By default, DNS prefetching is "on" for HTTP pages and "off" for HTTPS pages.
412   */
413  public static final String X_DNS_PREFETCH_CONTROL = "X-DNS-Prefetch-Control";
414  /**
415   * The HTTP <a href="http://html.spec.whatwg.org/multipage/semantics.html#hyperlink-auditing">
416   * {@code Ping-From}</a> header field name.
417   *
418   * @since 19.0
419   */
420  public static final String PING_FROM = "Ping-From";
421  /**
422   * The HTTP <a href="http://html.spec.whatwg.org/multipage/semantics.html#hyperlink-auditing">
423   * {@code Ping-To}</a> header field name.
424   *
425   * @since 19.0
426   */
427  public static final String PING_TO = "Ping-To";
428
429  /**
430   * The HTTP <a
431   * href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Link_prefetching_FAQ#As_a_server_admin.2C_can_I_distinguish_prefetch_requests_from_normal_requests.3F">{@code
432   * Purpose}</a> header field name.
433   *
434   * @since 28.0
435   */
436  public static final String PURPOSE = "Purpose";
437  /**
438   * The HTTP <a
439   * href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Link_prefetching_FAQ#As_a_server_admin.2C_can_I_distinguish_prefetch_requests_from_normal_requests.3F">{@code
440   * X-Purpose}</a> header field name.
441   *
442   * @since 28.0
443   */
444  public static final String X_PURPOSE = "X-Purpose";
445  /**
446   * The HTTP <a
447   * href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Link_prefetching_FAQ#As_a_server_admin.2C_can_I_distinguish_prefetch_requests_from_normal_requests.3F">{@code
448   * X-Moz}</a> header field name.
449   *
450   * @since 28.0
451   */
452  public static final String X_MOZ = "X-Moz";
453
454  /**
455   * The HTTP <a href="https://w3c.github.io/webappsec-fetch-metadata/">{@code Sec-Fetch-Dest}</a>
456   * header field name.
457   *
458   * @since 27.1
459   */
460  public static final String SEC_FETCH_DEST = "Sec-Fetch-Dest";
461  /**
462   * The HTTP <a href="https://w3c.github.io/webappsec-fetch-metadata/">{@code Sec-Fetch-Mode}</a>
463   * header field name.
464   *
465   * @since 27.1
466   */
467  public static final String SEC_FETCH_MODE = "Sec-Fetch-Mode";
468  /**
469   * The HTTP <a href="https://w3c.github.io/webappsec-fetch-metadata/">{@code Sec-Fetch-Site}</a>
470   * header field name.
471   *
472   * @since 27.1
473   */
474  public static final String SEC_FETCH_SITE = "Sec-Fetch-Site";
475  /**
476   * The HTTP <a href="https://w3c.github.io/webappsec-fetch-metadata/">{@code Sec-Fetch-User}</a>
477   * header field name.
478   *
479   * @since 27.1
480   */
481  public static final String SEC_FETCH_USER = "Sec-Fetch-User";
482  /**
483   * The HTTP <a href="https://w3c.github.io/webappsec-fetch-metadata/">{@code Sec-Metadata}</a>
484   * header field name.
485   *
486   * @since 26.0
487   */
488  public static final String SEC_METADATA = "Sec-Metadata";
489  /**
490   * The HTTP <a href="https://tools.ietf.org/html/draft-ietf-tokbind-https">{@code
491   * Sec-Token-Binding}</a> header field name.
492   *
493   * @since 25.1
494   */
495  public static final String SEC_TOKEN_BINDING = "Sec-Token-Binding";
496  /**
497   * The HTTP <a href="https://tools.ietf.org/html/draft-ietf-tokbind-ttrp">{@code
498   * Sec-Provided-Token-Binding-ID}</a> header field name.
499   *
500   * @since 25.1
501   */
502  public static final String SEC_PROVIDED_TOKEN_BINDING_ID = "Sec-Provided-Token-Binding-ID";
503  /**
504   * The HTTP <a href="https://tools.ietf.org/html/draft-ietf-tokbind-ttrp">{@code
505   * Sec-Referred-Token-Binding-ID}</a> header field name.
506   *
507   * @since 25.1
508   */
509  public static final String SEC_REFERRED_TOKEN_BINDING_ID = "Sec-Referred-Token-Binding-ID";
510  /**
511   * The HTTP <a href="https://tools.ietf.org/html/rfc6455">{@code Sec-WebSocket-Accept}</a> header
512   * field name.
513   *
514   * @since 28.0
515   */
516  public static final String SEC_WEBSOCKET_ACCEPT = "Sec-WebSocket-Accept";
517  /**
518   * The HTTP <a href="https://tools.ietf.org/html/rfc6455">{@code Sec-WebSocket-Extensions}</a>
519   * header field name.
520   *
521   * @since 28.0
522   */
523  public static final String SEC_WEBSOCKET_EXTENSIONS = "Sec-WebSocket-Extensions";
524  /**
525   * The HTTP <a href="https://tools.ietf.org/html/rfc6455">{@code Sec-WebSocket-Key}</a> header
526   * field name.
527   *
528   * @since 28.0
529   */
530  public static final String SEC_WEBSOCKET_KEY = "Sec-WebSocket-Key";
531  /**
532   * The HTTP <a href="https://tools.ietf.org/html/rfc6455">{@code Sec-WebSocket-Protocol}</a>
533   * header field name.
534   *
535   * @since 28.0
536   */
537  public static final String SEC_WEBSOCKET_PROTOCOL = "Sec-WebSocket-Protocol";
538  /**
539   * The HTTP <a href="https://tools.ietf.org/html/rfc6455">{@code Sec-WebSocket-Version}</a> header
540   * field name.
541   *
542   * @since 28.0
543   */
544  public static final String SEC_WEBSOCKET_VERSION = "Sec-WebSocket-Version";
545  /**
546   * The HTTP <a href="https://tools.ietf.org/html/rfc8586">{@code CDN-Loop}</a> header field name.
547   *
548   * @since 28.0
549   */
550  public static final String CDN_LOOP = "CDN-Loop";
551}