added basic support for htmx (ajax)

- if there is HX-Request header present we sent only a part of the whole html
- we return only specific stream defined by [out ...] ezc statement
- the name of the stream is passed in the 'frame' parameter
  (if not present then 'content' is assumed)
- added ezc function: winix_is_htmx_request

winixd/core/app.cpp

@@ -724,6 +724,25 @@ void App::SaveSessionsIfNeeded()
 
 
 
+const std::wstring * App::CreateFrameAnswer()
+{
+	Request & req = *cur.request;
+	auto i = req.out_streams.streams_map.begin();
+	const std::wstring * frame = cur.request->ParamValuep(L"frame");
+
+	for( ; i != req.out_streams.streams_map.end() ; ++i)
+	{
+		if( (frame && i->first == *frame) || (!frame && i->first == L"content") )
+		{
+			return &i->second->Str();
+			break;
+		}
+	}
+
+	return nullptr;
+}
+
+
 void App::CreateJSONAnswer()
 {
 	Request & req = *cur.request;
@@ -1764,11 +1783,12 @@ return header;
 
 void App::SendTextAnswer()
 {
-const std::wstring * source;
+const std::wstring * source = nullptr;
 bool compressing = false;
 int compress_encoding = 0;
 size_t output_size = 0;
 
+
 	Header header = GetHTTPStatusCode();
 
 	if( CanSendContent() )
@@ -1781,6 +1801,17 @@ size_t output_size = 0;
 			source = &json_out_stream.Str(); // json_out_stream was prepared by CreateJSONAnswer()
 		}
 		else
+		if( cur.request->headers_in.has_key(L"HX-Request") || cur.request->headers_in.has_key(L"hx_request") ) // fastcgi will change the header to hx_request
+		{
+			source = CreateFrameAnswer();
+
+			if( !source )
+			{
+				empty_response.clear();
+				source = &empty_response;
+			}
+		}
+		else
 		{
 			source = &cur.request->out_main_stream.Str();
 		}