"ERR_INVALID_HTTP_RESPONSE" error received in Chrome

[vikirj]

Hi,

I am using Mongoose version 7.14.

When I send a request from Postman, I receive a response successfully. However, when I send the same request from Chrome, the request sometimes fails even though the mg_http_reply function is called. Occasionally, the response is delayed.

Chrome returns the following error:
(failed) net::ERR_INVALID_HTTP_RESPONSE

Here is my sample code:

void event_handler(struct mg_connection *c, int ev, void *ev_data)
{
	std::string header = "Access-Control-Allow-Origin: *\r\nAccess-Control-Allow-Methods: GET,HEAD,PUT,PATCH,POST,DELETE\r\nContent-Type: text/plain\r\nConnection: keep-alive\r\n";
    if (ev == MG_EV_HTTP_MSG)
	{
        struct mg_http_message *hm = (struct mg_http_message *) ev_data;
		if (mg_match(hm->uri, mg_str("/test"), NULL))
			mg_http_reply(c, 200, header.c_str(), "Hello, HTTP!");
    } 
	else if (ev == MG_EV_WS_MSG)
	{
        struct mg_ws_message *wm = (struct mg_ws_message *) ev_data;
        mg_ws_send(c, wm->data.ptr, wm->data.len, WEBSOCKET_OP_TEXT);
    }
}

int main() 
{
    struct mg_mgr mgr;
    mg_mgr_init(&mgr);

    // Start HTTP and WebSocket server on the same port
    mg_http_listen(&mgr, "http://0.0.0.0:8000", event_handler, NULL);

    printf("Server started on http://localhost:8000\n");
    for (;;) 
        mg_mgr_poll(&mgr, 1000);

    mg_mgr_free(&mgr);
    return 0;
}

How to fix this issue?

[scaprile]

We do not offer support for previous releases unless you are a paying customer, in which case you need to contact Support as per your contract
Please migrate to latest release
https://github.com/cesanta/mongoose/releases/tag/7.16
I don't know what is Postman
I don't see you upgrading the connection
Please see our documentation, and follow the guidelines in our tutorials.
https://mongoose.ws/documentation/tutorials/websocket/websocket-server/
If you still have a problem:
Please sniff your network (using Wireshark, for example) and observe the traffic.
If, after your network inspection, you find an actual issue, feel free to open an issue, fill the issue template, and provide us with pertinent information (including useful network capture files; no snapshots, please attach capture files) in order to reproduce and fix the issue. We don't inspect your code for errors, please send the minimum piece of code that can reproduce the issue
Thank you

[vikirj]

Hi,

I’ve upgraded to version 7.16, where both WebSocket and HTTP are listening on the same port.

In my sample application, once the WebSocket connection opens, responses are sent via a thread. When sending a WebSocket response, if I make an HTTP request from Chrome, the first request successfully receives a response. However, subsequent requests do not receive responses, even though the “mg_http_reply” function is called.

Chrome returns the following error:
(failed) net::ERR_INVALID_HTTP_RESPONSE

Here is my sample code:

struct mg_mgr mgr;

void fn(struct mg_connection* c, int ev, void* ev_data)
{
    if (ev == MG_EV_HTTP_MSG)
    {
        struct mg_http_message* hm = (struct mg_http_message*)ev_data;
	if (mg_match(hm->uri, mg_str("/test"), NULL))
	{
		mg_http_reply(c, 200, "", "Hello, HTTP!");
		printf("Response sent\n");
	}
        if (mg_match(hm->uri, mg_str("/websocket"), NULL))
        {
            // Upgrade to websocket. From now on, a connection is a full-duplex
            // Websocket connection, which will receive MG_EV_WS_MSG events.
            mg_ws_upgrade(c, hm, NULL);
        }
    }

    else if (ev == MG_EV_WS_MSG)
    {
        struct mg_ws_message* wm = (struct mg_ws_message*)ev_data;
    }
}

void SendResponse()
{
	while (!boost::this_thread::interruption_requested())
	{
		std::string response = "opened";
		int length = response.size();
		for (struct mg_connection* connection = mgr.conns; connection != NULL; connection = connection->next)
			mg_ws_send(connection, response.c_str(), length, WEBSOCKET_OP_TEXT);

		std::this_thread::sleep_for(std::chrono::milliseconds(200));
	}
}

int main()
{
	mg_mgr_init(&mgr);

	// Start HTTP and WebSocket server on the same port
	mg_http_listen(&mgr, "http://0.0.0.0:8000", fn, NULL);

	std::thread th (SendResponse);

	printf("Server started on http://localhost:8000\n");
	for (;;)
		mg_mgr_poll(&mgr, 100);

	mg_mgr_free(&mgr);
	th.join();
	return 0;
}

When the application listens only for HTTP, it successfully receives responses.

Is it possible to listen to both WebSocket and HTTP on the same port?

[scaprile]

No, there is no HTTP and WebSocket listening on the same port; please understand the technologies you are working with, there is an HTTP connection that is upgraded to WebSocket. There is only one connection.
Please see our documentation, and follow the guidelines in our tutorials.
https://mongoose.ws/documentation/#websocket
Please see our documentation, and follow the guidelines in our tutorials. There is no example (nor doc) where we do something lilke what you are doing, violating basic Mongoose usage rules:
From the docs

NOTE: Since Mongoose's core is not protected against concurrent accesses, make sure that all mg_* API functions are called from the same thread or RTOS task.

If you absolutely need multi-threading, take the time to go through the user guide (linked above) and tutorials, there is one that shows you how to do multi-threading.