[core] OnlineFileSource - rate limit

6 files changed, 86 insertions, 2 deletions

diff --git a/src/mbgl/storage/response.cpp b/src/mbgl/storage/response.cpp
index 6809220166..a174339074 100644
--- a/src/mbgl/storage/response.cpp
+++ b/src/mbgl/storage/response.cpp
@@ -21,8 +21,8 @@ Response& Response::operator=(const Response& res) {
     return *this;
 }
 
-Response::Error::Error(Reason reason_, std::string message_)
-    : reason(reason_), message(std::move(message_)) {
+Response::Error::Error(Reason reason_, std::string message_, optional<Timestamp> retryAfter_)
+    : reason(reason_), message(std::move(message_)), retryAfter(std::move(retryAfter_)) {
 }
 
 std::ostream& operator<<(std::ostream& os, Response::Error::Reason r) {
@@ -35,6 +35,8 @@ std::ostream& operator<<(std::ostream& os, Response::Error::Reason r) {
         return os << "Response::Error::Reason::Server";
     case Response::Error::Reason::Connection:
         return os << "Response::Error::Reason::Connection";
+    case Response::Error::Reason::RateLimit:
+        return os << "Response::Error::Reason::RateLimit";
     case Response::Error::Reason::Other:
         return os << "Response::Error::Reason::Other";
     }
diff --git a/src/mbgl/util/chrono.cpp b/src/mbgl/util/chrono.cpp
index 55b8a86e39..f338f524b9 100644
--- a/src/mbgl/util/chrono.cpp
+++ b/src/mbgl/util/chrono.cpp
@@ -33,6 +33,10 @@ std::string iso8601(Timestamp timestamp) {
 Timestamp parseTimestamp(const char* timestamp) {
     return std::chrono::time_point_cast<Seconds>(std::chrono::system_clock::from_time_t(parse_date(timestamp)));
 }
+    
+Timestamp parseTimestamp(const int32_t timestamp) {
+    return std::chrono::time_point_cast<Seconds>(std::chrono::system_clock::from_time_t(timestamp));
+}
 
 } // namespace util
 
diff --git a/src/mbgl/util/http_header.cpp b/src/mbgl/util/http_header.cpp
index dceb331a3f..e337d4c8ab 100644
--- a/src/mbgl/util/http_header.cpp
+++ b/src/mbgl/util/http_header.cpp
@@ -28,6 +28,26 @@ CacheControl CacheControl::parse(const std::string& value) {
 optional<Timestamp> CacheControl::toTimePoint() const {
     return maxAge ? util::now() + Seconds(*maxAge) : optional<Timestamp>{};
 }
+    
+optional<Timestamp> parseRetryHeaders(const optional<std::string>& retryAfter,
+                                      const optional<std::string>& xRateLimitReset) {
+    if (retryAfter) {
+        try {
+            auto secs = std::chrono::seconds(std::stoi(*retryAfter));
+            return std::chrono::time_point_cast<Seconds>(std::chrono::system_clock::now() + secs);
+        } catch (...) {
+            return util::parseTimestamp((*retryAfter).c_str());
+        }
+    } else if (xRateLimitReset) {
+        try {
+            return util::parseTimestamp(std::stoi(*xRateLimitReset));
+        } catch (...) {
+            return {};
+        }
+    }
+    
+    return {};
+}
 
 } // namespace http
 } // namespace mbgl
diff --git a/src/mbgl/util/http_header.hpp b/src/mbgl/util/http_header.hpp
index 8a83356977..fa76cb724e 100644
--- a/src/mbgl/util/http_header.hpp
+++ b/src/mbgl/util/http_header.hpp
@@ -17,6 +17,9 @@ public:
 
     optional<Timestamp> toTimePoint() const;
 };
+    
+optional<Timestamp> parseRetryHeaders(const optional<std::string>& retryAfter,
+                                      const optional<std::string>& xRateLimitReset);
 
 } // namespace http
 } // namespace mbgl
diff --git a/src/mbgl/util/http_timeout.cpp b/src/mbgl/util/http_timeout.cpp
new file mode 100644
index 0000000000..ded0128ac9
--- /dev/null
+++ b/src/mbgl/util/http_timeout.cpp
@@ -0,0 +1,40 @@
+#include <mbgl/util/http_timeout.hpp>
+#include <mbgl/util/constants.hpp>
+
+namespace mbgl {
+namespace http {
+
+Duration errorRetryTimeout(Response::Error::Reason failedRequestReason, uint32_t failedRequests, optional<Timestamp> retryAfter) {
+
+    if (failedRequestReason == Response::Error::Reason::Server) {
+        // Retry after one second three times, then start exponential backoff.
+        return Seconds(failedRequests <= 3 ? 1 : 1u << std::min(failedRequests - 3, 31u));
+    } else if (failedRequestReason == Response::Error::Reason::Connection) {
+        // Immediate exponential backoff.
+        assert(failedRequests > 0);
+        return Seconds(1u << std::min(failedRequests - 1, 31u));
+    } else if (failedRequestReason == Response::Error::Reason::RateLimit) {
+        if (retryAfter) {
+            return *retryAfter - util::now();
+        } else {
+            //Default
+            return Seconds(util::DEFAULT_RATE_LIMIT_TIMEOUT);
+        }
+    } else {
+        // No error, or not an error that triggers retries.
+        return Duration::max();
+    }
+}
+
+Duration expirationTimeout(optional<Timestamp> expires, uint32_t expiredRequests) {
+    if (expiredRequests) {
+        return Seconds(1u << std::min(expiredRequests - 1, 31u));
+    } else if (expires) {
+        return std::max(Seconds::zero(), *expires - util::now());
+    } else {
+        return Duration::max();
+    }
+} 
+
+} // namespace http
+} // namespace mbgl
diff --git a/src/mbgl/util/http_timeout.hpp b/src/mbgl/util/http_timeout.hpp
new file mode 100644
index 0000000000..b694794997
--- /dev/null
+++ b/src/mbgl/util/http_timeout.hpp
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <mbgl/storage/response.hpp>
+#include <mbgl/util/optional.hpp>
+#include <mbgl/util/chrono.hpp>
+
+namespace mbgl {
+namespace http {
+
+Duration errorRetryTimeout(Response::Error::Reason failedRequestReason, uint32_t failedRequests, optional<Timestamp> retryAfter = {});
+
+Duration expirationTimeout(optional<Timestamp> expires, uint32_t expiredRequests);
+
+} // namespace http
+} // namespace mbgl