From 1d74b5e3115fc71855c9f925f5a52768ff24ae35 Mon Sep 17 00:00:00 2001
From: Veloman Yunkan <veloman.yunkan@gmail.com>
Date: Mon, 28 Nov 2022 12:08:51 +0400
Subject: [PATCH] Server sets the userlang cookie on every response

---
 src/server/request_context.cpp | 19 ++++++++++++++++++-
 src/server/response.cpp        |  3 +++
 test/server.cpp                | 15 +++++++--------
 3 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/src/server/request_context.cpp b/src/server/request_context.cpp
index 5e191afa7..db552a920 100644
--- a/src/server/request_context.cpp
+++ b/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";
diff --git a/src/server/response.cpp b/src/server/response.cpp
index 6020f9f78..c0cd8bd5d 100644
--- a/src/server/response.cpp
+++ b/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;
 
diff --git a/test/server.cpp b/test/server.cpp
index be611ad68..5874f8be2 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -998,42 +998,41 @@ TEST_F(ServerTest, UserLanguageControl)
   };
 
   const char* const NO_COOKIE = nullptr;
-  const char* const NO_SET_COOKIE = nullptr;
 
   const TestData testData[] = {
     {
       /*url*/ "/ROOT/content/zimfile/invalid-article",
       /*Accept-Language:*/ "",
       /*Request Cookie:*/       NO_COOKIE,
-      /*Response Set-Cookie:*/  NO_SET_COOKIE,
+      /*Response Set-Cookie:*/  "userlang=en",
       /* expected <h1> */ "Not Found"
     },
     {
       /*url*/ "/ROOT/content/zimfile/invalid-article?userlang=en",
       /*Accept-Language:*/ "",
       /*Request Cookie:*/       NO_COOKIE,
-      /*Response Set-Cookie:*/  NO_SET_COOKIE,
+      /*Response Set-Cookie:*/  "userlang=en",
       /* expected <h1> */ "Not Found"
     },
     {
       /*url*/ "/ROOT/content/zimfile/invalid-article?userlang=test",
       /*Accept-Language:*/ "",
       /*Request Cookie:*/       NO_COOKIE,
-      /*Response Set-Cookie:*/  NO_SET_COOKIE,
+      /*Response Set-Cookie:*/  "userlang=test",
       /* expected <h1> */ "[I18N TESTING] Content not found, but at least the server is alive"
     },
     {
       /*url*/ "/ROOT/content/zimfile/invalid-article",
       /*Accept-Language:*/ "*",
       /*Request Cookie:*/       NO_COOKIE,
-      /*Response Set-Cookie:*/  NO_SET_COOKIE,
+      /*Response Set-Cookie:*/  "userlang=en",
       /* expected <h1> */ "Not Found"
     },
     {
       /*url*/ "/ROOT/content/zimfile/invalid-article",
       /*Accept-Language:*/ "test",
       /*Request Cookie:*/       NO_COOKIE,
-      /*Response Set-Cookie:*/  NO_SET_COOKIE,
+      /*Response Set-Cookie:*/  "userlang=test",
       /* expected <h1> */ "[I18N TESTING] Content not found, but at least the server is alive"
     },
     {
@@ -1041,7 +1040,7 @@ TEST_F(ServerTest, UserLanguageControl)
       /*url*/ "/ROOT/content/zimfile/invalid-article?userlang=en",
       /*Accept-Language:*/ "test",
       /*Request Cookie:*/       NO_COOKIE,
-      /*Response Set-Cookie:*/  NO_SET_COOKIE,
+      /*Response Set-Cookie:*/  "userlang=en",
       /* expected <h1> */ "Not Found"
     },
     {
@@ -1051,7 +1050,7 @@ TEST_F(ServerTest, UserLanguageControl)
       /*url*/ "/ROOT/content/zimfile/invalid-article",
       /*Accept-Language:*/ "test;q=0.9, en;q=0.2",
       /*Request Cookie:*/       NO_COOKIE,
-      /*Response Set-Cookie:*/  NO_SET_COOKIE,
+      /*Response Set-Cookie:*/  "userlang=en",
       /* expected <h1> */ "Not Found"
     },
   };