Add support for 308 permanent redirects.

net/http/http_response_headers.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // The rules for header parsing were borrowed from Firefox:
 // http://lxr.mozilla.org/seamonkey/source/netwerk/protocol/http/src/nsHttpResponseHead.cpp
 // The rules for parsing content-types were also borrowed from Firefox:
 // http://lxr.mozilla.org/mozilla/source/netwerk/base/src/nsURLHelper.cpp#834
 
 #include "net/http/http_response_headers.h"
@@ skipping 904 matching lines @@
   return true;
 }
 
 // static
 bool HttpResponseHeaders::IsRedirectResponseCode(int response_code) {
   // Users probably want to see 300 (multiple choice) pages, so we don't count
   // them as redirects that need to be followed.
   return (response_code == 301 ||
           response_code == 302 ||
           response_code == 303 ||
-          response_code == 307);
+          response_code == 307 ||
+          response_code == 308);
 }
 
 // From RFC 2616 section 13.2.4:
 //
 // The calculation to determine if a response has expired is quite simple:
 //
 //   response_is_fresh = (freshness_lifetime > current_age)
 //
 // Of course, there are other factors that can force a response to always be
 // validated or re-fetched.
@@ skipping 78 matching lines @@
   //
   // From RFC 2616 section 14.9.4:
   //
   //   When the must-revalidate directive is present in a response received by
   //   a cache, that cache MUST NOT use the entry after it becomes stale to
   //   respond to a subsequent request without first revalidating it with the
   //   origin server. (I.e., the cache MUST do an end-to-end revalidation every
   //   time, if, based solely on the origin server's Expires or max-age value,
   //   the cached response is stale.)
   //
+  // https://datatracker.ietf.org/doc/draft-reschke-http-status-308/ is an
+  // experimental RFC that adds 308 permanent redirect as well, for which "any
+  // future references ... SHOULD use one of the returned URIs."

[mmenke, 2014/04/23 15:45:29]

Is there a non-expired doc I should be pointing to instead?  I can't seem to
find one.

   if ((response_code_ == 200 || response_code_ == 203 ||
        response_code_ == 206) &&
       !HasHeaderValue("cache-control", "must-revalidate")) {
     // TODO(darin): Implement a smarter heuristic.
     Time last_modified_value;
     if (GetLastModifiedValue(&last_modified_value)) {
       // The last-modified value can be a date in the past!
       if (last_modified_value <= date_value)
         return (date_value - last_modified_value) / 10;
     }
   }
 
   // These responses are implicitly fresh (unless otherwise overruled):
-  if (response_code_ == 300 || response_code_ == 301 || response_code_ == 410)
+  if (response_code_ == 300 || response_code_ == 301 || response_code_ == 308 ||
+      response_code_ == 410) {
     return TimeDelta::Max();
+  }
 
   return TimeDelta();  // not fresh
 }
 
 // From RFC 2616 section 13.2.3:
 //
 // Summary of age calculation algorithm, when a cache receives a response:
 //
 //   /*
 //    * age_value
@@ skipping 448 matching lines @@
     // should not generate representation metadata other than Cache-Control,
     // Content-Location, Date, ETag, Expires, and Vary.
     return ProxyService::MISSING_VIA_HEADER;
   }
   // There is no bypass event.
   return ProxyService::BYPASS_EVENT_TYPE_MAX;
 }
 #endif  // defined(SPDY_PROXY_AUTH_ORIGIN)
 
 }  // namespace net