Do not use date::to_stream since date might only use C locale

include/zeep/unicode-support.hpp

@@ -206,6 +206,59 @@ std::tuple<unicode,Iter> get_first_char(Iter ptr, Iter end)
 
 // --------------------------------------------------------------------
 
+/**
+ * @brief Return a std::wstring for the UTF-8 encoded std::string @a s.
+ * @note This simplistic code assumes all unicode characters will fit in a wchar_t
+ * 
+ * @param s The input string
+ * @return std::wstring The recoded output string
+ */
+inline std::wstring convert_s2w(std::string_view s)
+{
+	auto b = s.begin();
+	auto e = s.end();
+
+	std::wstring result;
+
+	while (b != e)
+	{
+		const auto &[uc, i] = get_first_char(b, e);
+		if (not uc)
+			break;
+
+		result += static_cast<wchar_t>(uc);
+		b = i;
+	}
+
+	return result;
+}
+
+/**
+ * @brief Return a std::string encoded in UTF-8 for the input std::wstring @a s.
+ * @note This simplistic code assumes input contains only UCS-2 characters which are deprecated, I know.
+ * This means UTF-16 surrogates are ruined.
+ * 
+ * @param s The input string
+ * @return std::string The recoded output string
+ */
+inline std::string convert_w2s(std::wstring_view s)
+{
+	std::string result;
+
+	for (unicode ch : s)
+		append(result, ch);
+
+	return result;
+}
+
+// --------------------------------------------------------------------
+
+/**
+ * @brief Return a hexadecimal string representation for the numerical value in @a i
+ * 
+ * @param i The value to convert
+ * @return std::string The hexadecimal representation
+ */
 inline std::string to_hex(uint32_t i)
 {
 	char s[sizeof(i) * 2 + 3];

lib-http/src/el-processing.cpp

@@ -1520,20 +1520,14 @@ class date_expr_util_object : public expression_utility_object<date_expr_util_ob
 
 				auto st = value_serializer<std::chrono::system_clock::time_point>::from_string(t);
 
-#if __has_include(<date/date.h>)
-				std::ostringstream os;
-				os << date::format(scope.get_request().get_locale(), f, st);
-#else
 				std::wostringstream os;
 				os.imbue(scope.get_request().get_locale());
 
-				std::wstring_convert<std::codecvt_utf8<wchar_t>> myconv;
-				std::wstring time = myconv.from_bytes(f);
+				auto tt = std::chrono::system_clock::to_time_t(st);
+				auto wf = convert_s2w(f);
 
-				auto t = std::chrono::system_clock::to_time_t(st);
-				os << std::put_time(std::gmtime(&t), time.c_str());
-#endif
-				result = os.str();
+				os << std::put_time<wchar_t>(std::gmtime(&tt), wf.c_str());
+				result = convert_w2s(os.str());
 			}
 		}