From dcc6f12c205a72604af0ece19750816a404da1ca Mon Sep 17 00:00:00 2001
From: Victor Vazquez <victor.vazquez@microsoft.com>
Date: Wed, 20 Oct 2021 11:43:28 -0700
Subject: [PATCH] force http 1.1 on the libcurl transport adapter (#2978)

* force http 1.1

* update wording
---
 sdk/core/azure-core/CHANGELOG.md           |  2 ++
 sdk/core/azure-core/src/http/curl/curl.cpp | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/sdk/core/azure-core/CHANGELOG.md b/sdk/core/azure-core/CHANGELOG.md
index 7b5898bdf..b5e36ae25 100644
--- a/sdk/core/azure-core/CHANGELOG.md
+++ b/sdk/core/azure-core/CHANGELOG.md
@@ -10,6 +10,8 @@
 
 ### Bugs Fixed
 
+[2848](https://github.com/Azure/azure-sdk-for-cpp/issues/2848) Update the libcurl transport adapter to work with HTTP/1.1 only.
+
 ### Other Changes
 
 ## 1.2.1 (2021-09-02)
diff --git a/sdk/core/azure-core/src/http/curl/curl.cpp b/sdk/core/azure-core/src/http/curl/curl.cpp
index e2d062b29..4c957995c 100644
--- a/sdk/core/azure-core/src/http/curl/curl.cpp
+++ b/sdk/core/azure-core/src/http/curl/curl.cpp
@@ -1407,6 +1407,16 @@ std::unique_ptr<CurlNetworkConnection> CurlConnectionPool::ExtractOrCreateCurlCo
     }
   }
 
+  // curl-transport adapter supports only HTTP/1.1
+  // https://github.com/Azure/azure-sdk-for-cpp/issues/2848
+  // The libcurl uses HTTP/2 by default, if it can be negotiated with a server on handshake.
+  if (!SetLibcurlOption(newHandle, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1, &result))
+  {
+    throw Azure::Core::Http::TransportException(
+        _detail::DefaultFailedToGetNewConnectionTemplate + host + ". Failed to set libcurl HTTP/1.1"
+        + ". " + std::string(curl_easy_strerror(result)));
+  }
+
   auto performResult = curl_easy_perform(newHandle);
   if (performResult != CURLE_OK)
   {