Server sets the userlang cookie on every response

src/server/request_context.cpp

@@ -25,6 +25,7 @@
 #include <sstream>
 #include <cstdio>
 #include <atomic>
+#include <cctype>
 
 #include "tools/stringTools.h"
 
@@ -63,6 +64,22 @@ fullURL2LocalURL(const std::string& full_url, const std::string& rootLocation)
   }
 }
 
+std::string parseAcceptLanguageHeader(const std::string& s)
+{
+  // TODO: implement properly
+
+  if ( s.empty() )
+    return "en";
+
+  for ( const char c :  s ) {
+    if ( ! std::isalpha(c) ) {
+      return "en";
+    }
+  }
+
+  return s;
+}
+
 } // unnamed namespace
 
 RequestContext::RequestContext(struct MHD_Connection* connection,
@@ -204,7 +221,7 @@ std::string RequestContext::get_user_language() const
   } catch(const std::out_of_range&) {}
 
   try {
-    return get_header("Accept-Language");
+    return parseAcceptLanguageHeader(get_header("Accept-Language"));
   } catch(const std::out_of_range&) {}
 
   return "en";

src/server/response.cpp

@@ -387,6 +387,9 @@ MHD_Result Response::send(const RequestContext& request, MHD_Connection* connect
     MHD_add_response_header(response, p.first.c_str(), p.second.c_str());
   }
 
+  const std::string cookie = "userlang=" + request.get_user_language();
+  MHD_add_response_header(response, MHD_HTTP_HEADER_SET_COOKIE, cookie.c_str());
+
   if (m_returnCode == MHD_HTTP_OK && m_byteRange.kind() == ByteRange::RESOLVED_PARTIAL_CONTENT)
     m_returnCode = MHD_HTTP_PARTIAL_CONTENT;