1 files changed, 17 insertions, 0 deletions
diff --git a/indra/llcorehttp/_httpoprequest.cpp b/indra/llcorehttp/_httpoprequest.cpp
index 6186e7a308..bde1aed910 100644
--- a/indra/llcorehttp/_httpoprequest.cpp
+++ b/indra/llcorehttp/_httpoprequest.cpp
@@ -513,7 +513,9 @@ HttpStatus HttpOpRequest::prepareRequest(HttpService * service)
     check_curl_easy_setopt(mCurlHandle, CURLOPT_NOPROGRESS, 1);
     check_curl_easy_setopt(mCurlHandle, CURLOPT_URL, mReqURL.c_str());
     check_curl_easy_setopt(mCurlHandle, CURLOPT_PRIVATE, getHandle());
+#if LIBCURL_VERSION_MAJOR < 8
     check_curl_easy_setopt(mCurlHandle, CURLOPT_ENCODING, "");
+#endif
 
     check_curl_easy_setopt(mCurlHandle, CURLOPT_AUTOREFERER, 1);
     check_curl_easy_setopt(mCurlHandle, CURLOPT_MAXREDIRS, HTTP_REDIRECTS_DEFAULT);
@@ -538,6 +540,7 @@ HttpStatus HttpOpRequest::prepareRequest(HttpService * service)
     long sslHostV(0L);
     long dnsCacheTimeout(-1L);
     long nobody(0L);
+    curl_off_t lastModified(0L);
 
     if (mReqOptions)
     {
@@ -546,6 +549,7 @@ HttpStatus HttpOpRequest::prepareRequest(HttpService * service)
         sslHostV = mReqOptions->getSSLVerifyHost() ? 2L : 0L;
         dnsCacheTimeout = mReqOptions->getDNSCacheTimeout();
         nobody = mReqOptions->getHeadersOnly() ? 1L : 0L;
+        lastModified = (curl_off_t)mReqOptions->getLastModified();
     }
     check_curl_easy_setopt(mCurlHandle, CURLOPT_FOLLOWLOCATION, follow_redirect);
 
@@ -554,6 +558,17 @@ HttpStatus HttpOpRequest::prepareRequest(HttpService * service)
 
     check_curl_easy_setopt(mCurlHandle, CURLOPT_NOBODY, nobody);
 
+    if (lastModified)
+    {
+        check_curl_easy_setopt(mCurlHandle, CURLOPT_TIMECONDITION, CURL_TIMECOND_IFMODSINCE);
+#if (LIBCURL_VERSION_NUM >= 0x073B00)
+        // requires curl 7.59.0
+        check_curl_easy_setopt(mCurlHandle, CURLOPT_TIMEVALUE_LARGE, lastModified);
+#else
+        check_curl_easy_setopt(mCurlHandle, CURLOPT_TIMEVALUE, (long)lastModified);
+#endif
+    }
+
     // The Linksys WRT54G V5 router has an issue with frequent
     // DNS lookups from LAN machines.  If they happen too often,
     // like for every HTTP request, the router gets annoyed after
@@ -603,7 +618,9 @@ HttpStatus HttpOpRequest::prepareRequest(HttpService * service)
     case HOR_POST:
         {
             check_curl_easy_setopt(mCurlHandle, CURLOPT_POST, 1);
+#if LIBCURL_VERSION_MAJOR < 8
             check_curl_easy_setopt(mCurlHandle, CURLOPT_ENCODING, "");
+#endif
             long data_size(0);
             if (mReqBody)
             {