commit fccbf2db6bcb97e556e46f8ca15437de38657cf5
author sorin <sorin@chromium.org> Mon Apr 04 20:34:34 2016
committer Commit bot <commit-bot@chromium.org> Mon Apr 04 20:36:03 2016
tree 3cb5ce9f9d544c8e11bf8d09ffd06227a5fcc68e
parent e7fe613bd9261fad4ceb22bea0446854ce975273

Allow fallback from https to http for component update checks.

Component updater relies on its custom message signing protocol to
guarantee the integrity of update checks.

As a failover mechanism and to improve the update success rates,
fallback to HTTP is allowed. This is similar to
what Google Update (Omaha) has been doing.

BUG=590070

Review URL: https://codereview.chromium.org/1740333002

Cr-Commit-Position: refs/heads/master@{#384993}

components/update_client/request_sender.h

diff --git a/components/update_client/request_sender.h b/components/update_client/request_sender.h
index ddf5cca..b5daaa2e 100644
--- a/components/update_client/request_sender.h
+++ b/components/update_client/request_sender.h
@@ -5,6 +5,8 @@
 #ifndef COMPONENTS_UPDATE_CLIENT_REQUEST_SENDER_H_
 #define COMPONENTS_UPDATE_CLIENT_REQUEST_SENDER_H_
 
+#include <stdint.h>
+
 #include <string>
 #include <vector>
 
@@ -35,8 +37,13 @@
 class RequestSender : public net::URLFetcherDelegate {
  public:
   // If |error| is 0, then the response is provided in the |response| parameter.
-  using RequestSenderCallback =
-      base::Callback<void(int error, const std::string& response)>;
+  // |retry_after_sec| contains the value of the X-Retry-After response header,
+  // when the response was received from a cryptographically secure URL. The
+  // range for this value is [-1, 86400]. If |retry_after_sec| is -1 it means
+  // that the header could not be found, or trusted, or had an invalid value.
+  // The upper bound represents a delay of one day.
+  using RequestSenderCallback = base::Callback<
+      void(int error, const std::string& response, int retry_after_sec)>;
 
   static int kErrorResponseNotTrusted;
 
@@ -57,9 +64,15 @@
   // Decodes and returns the public key used by CUP.
   static std::string GetKey(const char* key_bytes_base64);
 
-  // Returns the Etag of the server response or an empty string if the
-  // Etag is not available.
-  static std::string GetServerETag(const net::URLFetcher* source);
+  // Returns the string value of a header of the server response or an empty
+  // string if the header is not available.
+  static std::string GetStringHeaderValue(const net::URLFetcher* source,
+                                          const char* header_name);
+
+  // Returns the integral value of a header of the server response or -1 if
+  // if the header is not available or a conversion error has occured.
+  static int64_t GetInt64HeaderValue(const net::URLFetcher* source,
+                                     const char* header_name);
 
   // Overrides for URLFetcherDelegate.
   void OnURLFetchComplete(const net::URLFetcher* source) override;
@@ -67,19 +80,20 @@
   // Implements the error handling and url fallback mechanism.
   void SendInternal();
 
-  // Called when SendInternal complets. |response_body|and |response_etag|
+  // Called when SendInternal completes. |response_body| and |response_etag|
   // contain the body and the etag associated with the HTTP response.
   void SendInternalComplete(int error,
                             const std::string& response_body,
-                            const std::string& response_etag);
+                            const std::string& response_etag,
+                            int retry_after_sec);
 
   // Helper function to handle a non-continuable error in Send.
-  void HandleSendError(int error);
+  void HandleSendError(int error, int retry_after_sec);
 
   base::ThreadChecker thread_checker_;
 
   const scoped_refptr<Configurator> config_;
-  bool use_signing_;
+  bool use_signing_;  // True if CUP signing is used.
   std::vector<GURL> urls_;
   std::string request_body_;
   RequestSenderCallback request_sender_callback_;