Fixing json library locale issues on Windows.

Author: stgates

Release/include/cpprest/asyncrt_utils.h

@@ -159,6 +159,37 @@ namespace conversions
 
 namespace details
 {
+    /// <summary>
+    /// Cross platform RAII container for setting thread local locale.
+    /// </summary>
+    class thread_local_locale
+    {
+    public:
+
+        thread_local_locale(const char * locale)
+        {
+#ifdef _MS_WINDOWS
+            _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
+            m_prevLocale = setlocale(LC_ALL, locale);
+#endif
+        }
+
+        ~thread_local_locale()
+        {
+            if (m_prevLocale != nullptr)
+            {
+#ifdef _MS_WINDOWS
+                setlocale(LC_ALL, m_prevLocale);
+#endif
+            }
+        }
+
+    private:
+#ifdef _MS_WINDOWS
+        char * m_prevLocale;
+#endif
+    };
+
     /// <summary>
     /// Our own implementation of alpha numeric instead of std::isalnum to avoid
     /// taking global lock for performance reasons.

Release/include/cpprest/json.h

@@ -44,7 +44,6 @@ namespace web
 /// Library for parsing and serializing JSON values to and from C++ types.
 namespace json
 {
-
     // Various forward declarations.
     namespace details 
     {
@@ -64,8 +63,11 @@ namespace json
     }
 
     /// <summary>
-    /// Preserve the order of the name/value pairs when parsing a JSON object
+    /// Preserve the order of the name/value pairs when parsing a JSON object.
+    /// The default is false, which can yield better performance.
     /// </summary>
+    /// <param name="keep_order"><c>true</c> if ordering should be preserved when parsing, <c>false</c> otherwise.</param>
+    /// <remarks>Note this is a global setting and affects all JSON parsing done.</remarks>
     void _ASYNCRTIMP keep_object_element_order(bool keep_order);
 
 #ifdef _MS_WINDOWS
@@ -1415,8 +1417,7 @@ namespace json
             virtual void serialize_impl(std::wstring& str) const
             {
                 serialize_impl_char_type(str);
-            }
-            
+            }  
 #endif
 
         protected:

Release/src/json/json.cpp

@@ -106,7 +106,7 @@ web::json::value::value(utility::string_t value) :
     { }
 
 web::json::value::value(const utility::char_t* value) : 
-    m_value(utility::details::make_unique<web::json::details::_String>(utility::string_t(value)))
+    m_value(utility::details::make_unique<web::json::details::_String>(value))
 #ifdef ENABLE_JSON_VALUE_VISUALIZER
     ,m_kind(value::String)
 #endif
@@ -363,7 +363,11 @@ bool web::json::details::_Object::has_field(const utility::string_t &key) const
     return m_object.find(key) != m_object.end();
 }
 
-utility::string_t json::value::to_string() const { return m_value->to_string(); }
+utility::string_t json::value::to_string() const 
+{ 
+    utility::details::thread_local_locale("C");
+    return m_value->to_string(); 
+}
 
 bool json::value::operator==(const json::value &other) const
 {
@@ -411,7 +415,6 @@ const web::json::value& web::json::value::at(const utility::string_t& key) const
     return this->as_object().at(key);
 }
 
-
 web::json::value& web::json::value::operator [] (const utility::string_t &key)
 {
     if ( this->is_null() )

Release/src/json/json_parsing.cpp

@@ -67,7 +67,6 @@ void CreateError(const Token &tk, const utility::string_t &message)
     throw web::json::json_exception(os.str().c_str());
 }
 
-    
 template <typename CharType>
 class JSON_Parser
 {
@@ -195,7 +194,7 @@ class JSON_StreamParser : public JSON_Parser<CharType>
     {
 public:
     JSON_StreamParser(std::basic_istream<CharType> &stream)
-        : m_streambuf(stream.rdbuf())
+        : m_streambuf(stream.rdbuf()), m_locale("C")
     {
     }
 
@@ -206,14 +205,16 @@ class JSON_StreamParser : public JSON_Parser<CharType>
 
 private:
     typename std::basic_streambuf<CharType, std::char_traits<CharType>>* m_streambuf;
+
+    ::utility::details::thread_local_locale m_locale;
 };
 
 template <typename CharType>
 class JSON_StringParser : public JSON_Parser<CharType>
 {
 public:
-    JSON_StringParser(const std::basic_string<CharType>& string) 
-        : m_position(&string[0])
+    JSON_StringParser(const std::basic_string<CharType>& string)
+        : m_position(&string[0]), m_locale("C")
     {
         m_startpos = m_position;
         m_endpos = m_position+string.size();
@@ -232,6 +233,7 @@ class JSON_StringParser : public JSON_Parser<CharType>
     const CharType* m_position;
     const CharType* m_startpos;
     const CharType* m_endpos;
+    ::utility::details::thread_local_locale m_locale;
 };
 
 

Release/src/json/json_serialization.cpp

@@ -28,20 +28,20 @@
 #include "stdafx.h"
 #include <stdio.h>
 
-#pragma warning(disable : 4127) // allow expressions like while(true) pass 
 using namespace web;
 using namespace web::json;
 using namespace utility;
 using namespace utility::conversions;
 
-
 //
 // JSON Serialization
 //
 
 #ifdef _MS_WINDOWS
 void web::json::value::serialize(std::ostream& stream) const
 { 
+    utility::details::thread_local_locale("C");
+
     // This has better performance than writing directly to stream.
     std::string str;
     m_value->serialize_impl(str);
@@ -55,6 +55,8 @@ void web::json::value::format(std::basic_string<wchar_t> &string) const
 
 void web::json::value::serialize(utility::ostream_t &stream) const 
 {
+    utility::details::thread_local_locale("C");
+
     // This has better performance than writing directly to stream.
     utility::string_t str;
     m_value->serialize_impl(str);
@@ -157,7 +159,7 @@ void web::json::details::_Number::format(std::basic_string<char>& stream) const
         const auto numChars = strnlen_s(tempBuffer, tempSize);
         stream.append(tempBuffer, numChars);
 #else
-        std::stringstream ss;
+        std::stringstream ss; // TODO - also consider replacing with snprintf...
         if (m_number.m_type == number::type::signed_type)
             ss << m_number.m_intval;
         else
@@ -235,4 +237,8 @@ utility::string_t web::json::value::as_string() const
     return m_value->as_string();
 }
 
-utility::string_t json::value::serialize() const { return m_value->to_string(); }
+utility::string_t json::value::serialize() const 
+{ 
+    utility::details::thread_local_locale("C");
+    return m_value->to_string(); 
+}

Release/tests/Functional/json/parsing_tests.cpp

@@ -566,6 +566,32 @@ TEST(keep_order_while_parsing)
     VERIFY_ARE_EQUAL(obj[U("a")].as_integer(), 4);
 }
 
+TEST(non_default_locale)
+{
+    char * prevLocale = setlocale(LC_ALL, "fr-FR");
+
+    // string serialize
+    utility::string_t str(U("[true,false,-1.55,5,null,{\"abc\":5555}]"));
+    json::value v = json::value::parse(str);
+    VERIFY_ARE_EQUAL(str, v.serialize());
+
+    // cpprestsdk stream serialize
+    utility::stringstream_t stream;
+    stream << v;
+    utility::string_t serializedStr;
+    stream >> serializedStr;
+    VERIFY_ARE_EQUAL(str, serializedStr);
+
+    // std stream serialize
+    std::stringstream stdStream;
+    v.serialize(stdStream);
+    std::string stdStr;
+    stdStream >> stdStr;
+    VERIFY_ARE_EQUAL(str, utility::conversions::to_string_t(stdStr));
+
+    setlocale(LC_ALL, prevLocale);
+}
+
 } // SUITE(parsing_tests)
 
 }}}