1 // Copyright 2012 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef NET_HTTP_HTTP_VARY_DATA_H_ 6 #define NET_HTTP_HTTP_VARY_DATA_H_ 7 8 #include "base/hash/md5.h" 9 #include "net/base/net_export.h" 10 11 namespace base { 12 class Pickle; 13 class PickleIterator; 14 } 15 16 namespace net { 17 18 struct HttpRequestInfo; 19 class HttpResponseHeaders; 20 21 // Used to implement the HTTP/1.1 Vary header. This class contains a MD5 hash 22 // over the request headers indicated by a Vary header. 23 // 24 // While RFC 2616 requires strict request header comparisons, it is much 25 // cheaper to store a MD5 sum, which should be sufficient. Storing a hash also 26 // avoids messy privacy issues as some of the request headers could hold 27 // sensitive data (e.g., cookies). 28 // 29 // NOTE: This class does not hold onto the contents of the Vary header. 30 // Instead, it relies on the consumer to store that and to supply it again to 31 // the MatchesRequest function for comparing against future HTTP requests. 32 // 33 class NET_EXPORT_PRIVATE HttpVaryData { 34 public: 35 HttpVaryData(); 36 is_valid()37 bool is_valid() const { return is_valid_; } 38 39 // Initialize from a request and its corresponding response headers. 40 // 41 // Returns true if a Vary header was found in the response headers and that 42 // Vary header was not empty. Upon success, the object is also marked as valid 43 // such that is_valid() will return true. Otherwise, false is returned to 44 // indicate that this object is marked as invalid. 45 // 46 bool Init(const HttpRequestInfo& request_info, 47 const HttpResponseHeaders& response_headers); 48 49 // Initialize from a pickle that contains data generated by a call to the 50 // vary data's Persist method. 51 // 52 // Upon success, true is returned and the object is marked as valid such that 53 // is_valid() will return true. Otherwise, false is returned to indicate 54 // that this object is marked as invalid. 55 // 56 bool InitFromPickle(base::PickleIterator* pickle_iter); 57 58 // Call this method to persist the vary data. Illegal to call this on an 59 // invalid object. 60 void Persist(base::Pickle* pickle) const; 61 62 // Call this method to test if the given request matches the previous request 63 // with which this vary data corresponds. The |cached_response_headers| must 64 // be the same response headers used to generate this vary data. 65 bool MatchesRequest(const HttpRequestInfo& request_info, 66 const HttpResponseHeaders& cached_response_headers) const; 67 68 private: 69 // Returns the corresponding request header value. 70 static std::string GetRequestValue(const HttpRequestInfo& request_info, 71 const std::string& request_header); 72 73 // Append to the MD5 context for the given request header. 74 static void AddField(const HttpRequestInfo& request_info, 75 const std::string& request_header, 76 base::MD5Context* context); 77 78 // A digested version of the request headers corresponding to the Vary header. 79 base::MD5Digest request_digest_; 80 81 // True when request_digest_ contains meaningful data. 82 bool is_valid_ = false; 83 }; 84 85 } // namespace net 86 87 #endif // NET_HTTP_HTTP_VARY_DATA_H_ 88