Add transfer rate limit support to NetworkCurl

This can be used for testing for poor network connectivity
Introduce max_transfer_bytes_per_second field in
NetworkInitializationSettings. When non-zero, this value is applied
per connection via CURLOPT_MAX_RECV_SPEED_LARGE and
CURLOPT_MAX_SEND_SPEED_LARGE (requires libcurl >= 7.15.5).

Relates-To: HERESUP-62561
Signed-off-by: Ming Li <ming.5.li@here.com>
Signed-off-by: Rustam Gamidov <ext-rustam.gamidov@here.com>

Author: rustam-gamidov-here

olp-cpp-sdk-core/include/olp/core/http/NetworkInitializationSettings.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2023-2025 HERE Europe B.V.
+ * Copyright (C) 2023-2026 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,8 @@
 
 #pragma once
 
+#include <string>
+
 #include <olp/core/CoreApi.h>
 #include <olp/core/http/CertificateSettings.h>
 #include <olp/core/porting/optional.h>
@@ -48,6 +50,14 @@ struct CORE_API NetworkInitializationSettings {
    * setting.
    */
   porting::optional<std::string> diagnostic_output_path = porting::none;
+
+  /**
+   * @brief Global transfer limit in bytes per second. A value of 0 means no
+   * limit. This value is applied per connection to cURL via
+   * CURLOPT_MAX_RECV_SPEED_LARGE / CURLOPT_MAX_SEND_SPEED_LARGE where
+   * supported.
+   */
+  size_t max_transfer_bytes_per_second = 0u;
 };
 
 }  // namespace http

olp-cpp-sdk-core/src/http/curl/NetworkCurl.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019-2025 HERE Europe B.V.
+ * Copyright (C) 2019-2026 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -406,10 +406,16 @@ NetworkCurl::NetworkCurl(NetworkInitializationSettings settings)
     : handles_(settings.max_requests_count),
       static_handle_count_(
           std::max(static_cast<size_t>(1u), settings.max_requests_count / 4u)),
-      certificate_settings_(std::move(settings.certificate_settings)) {
+      certificate_settings_(std::move(settings.certificate_settings)),
+      max_transfer_bytes_per_second_(settings.max_transfer_bytes_per_second) {
   OLP_SDK_LOG_TRACE(kLogTag, "Created NetworkCurl with address="
                                  << this << ", handles_count="
                                  << settings.max_requests_count);
+  if (max_transfer_bytes_per_second_ > 0) {
+    OLP_SDK_LOG_INFO_F(kLogTag, "max_transfer_bytes_per_second=%zu",
+                       max_transfer_bytes_per_second_);
+  }
+
   auto error = curl_global_init(CURL_GLOBAL_ALL);
   curl_initialized_ = (error == CURLE_OK);
   if (!curl_initialized_) {
@@ -858,6 +864,17 @@ ErrorCode NetworkCurl::SendImplementation(
                    config.GetMaxConnectionLifetime().count() ? 1L : 0L);
 #endif
 
+#if CURL_AT_LEAST_VERSION(7, 15, 5)
+  // Refer to https://curl.se/libcurl/c/CURLOPT_MAX_RECV_SPEED_LARGE.html for
+  // the minimum supported version.
+  if (max_transfer_bytes_per_second_ > 0) {
+    curl_off_t speed_limit =
+        static_cast<curl_off_t>(max_transfer_bytes_per_second_);
+    curl_easy_setopt(curl_handle, CURLOPT_MAX_RECV_SPEED_LARGE, speed_limit);
+    curl_easy_setopt(curl_handle, CURLOPT_MAX_SEND_SPEED_LARGE, speed_limit);
+  }
+#endif
+
   {
     std::lock_guard<std::mutex> lock(event_mutex_);
     AddEvent(EventInfo::Type::SEND_EVENT, handle);

olp-cpp-sdk-core/src/http/curl/NetworkCurl.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019-2025 HERE Europe B.V.
+ * Copyright (C) 2019-2026 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -373,6 +373,10 @@ class NetworkCurl : public Network,
   /// blobs so cURL does not need to copy them.
   CertificateSettings certificate_settings_;
 
+  /// Maximum transfer rate in bytes per second applied per connection (0 =
+  /// unlimited).
+  size_t max_transfer_bytes_per_second_{0u};
+
 #ifdef OLP_SDK_CURL_HAS_SUPPORT_SSL_BLOBS
   /// SSL certificate blobs.
   porting::optional<SslCertificateBlobs> ssl_certificates_blobs_;