Connect to a websocket with http listener is not working

[SasinduDilshara]

I tried to initiate a websocket connection with following program.

import ballerina/http;
import ballerina/graphql;
import ballerina/websocket;

listener http:Listener 'listener = check new(9090);
listener graphql:Listener graphqlListener = new('listener);
listener websocket:Listener wsListener = new('listener);

service /ws on wsListener {
    resource function get .(string id, string 'type) returns websocket:Service {
        if 'type == ORDER_TYPE {
            ...
        } else {
            ...
        }
    }
}

This not worked properly. I got the following response

Status Code: 500 Internal Server Error
Request Headers
Sec-WebSocket-Version: 13
Sec-WebSocket-Key: PWM4ryWB6hBgeVhJbUyEvA==
Connection: Upgrade
Upgrade: websocket
Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits
Host: localhost:9090

[ThisaruGuruge]

This probably happens due to the HTTP version mismatch. WebSockets support the HTTP 1.1 version. In Ballerina, the default HTTP version is 2.0 (in the ballerina/http module). Change the HTTP version of the listener and this should work.

However, I think ideally it should be handled from the WebSocket module itself.

listener http:Listener 'listener = check new(9090, {
    httpVersion: http:HTTP_1_1
});

[t-trafer]

hi, i would like to work on this issue

[ThisaruGuruge]

👋 Welcome, @t-trafer! 🚀

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[ThisaruGuruge]

hi, i would like to work on this issue

I have assigned the issue for you.

To give you some context,

This error is occurring due to the Ballerina HTTP module using HTTP 2.0 by default, but the WebSocket needs HTTP 1.1. Therefore, when you pass an HTTP listener with default configs, the WebSocket listener initialization fails.

There are two approaches of handling this:

1. Return an error if the HTTP listener has non compatible HTTP version
2. Forcefully change the HTTP version to a compatible one inside the WebSocket listener initialization.

@Bhashinee any thoughts on this?

[Bhashinee]

I prefer the first one. With the second approach, we are internally doing manipulations that are not visible to the user. So when this listener is used with another HTTP service, the user might think it is running as an HTTP/2 listener even though we have changed that internally to use HTTP/1.1. With the first approach, the user becomes aware of that change as he is the one who has to configure it in the listener.

[ThisaruGuruge]

I prefer the first one. With the second approach, we are internally doing manipulations that are not visible to the user. So when this listener is used with another HTTP service, the user might think it is running as an HTTP/2 listener even though we have changed that internally to use HTTP/1.1. With the first approach, the user becomes aware of that change as he is the one who has to configure it in the listener.

+1

[t-trafer]

Thanks for the heads up and suggestions! going ahead with the first approach

[keizer619]

@t-trafer Are you working on this?

[m-tabish]

Kindly assign this to me, under Hacktoberfest 2024. I will try to solve this

[ThisaruGuruge]

Kindly assign this to me, under Hacktoberfest 2024. I will try to solve this

Thank you for participating in Hacktoberfest with Ballerina. I have assigned the issue to you now.