Regards Emscripten Socket Server Creation

[Aitha Tarun]

Could anyone provide a sample code for creating a socket server code that can also work from web browsers and accept incoming connections?

[Floh]

I might be wrong but I don't think that's possible. First, you can't expose a TCP-compatible socket in browsers (Emscripten's TCP API is an emulation wrapper over WebSockets, which are not protocol-compatible with 'raw' TCP).

WebSocket in the browser can only implement a client interface (e.g. it cannot accept incoming connections, only connect to a 'native' WebSocket server).

WebRTC data channels might allow to implement something that looks like a server running in a browser (because it's a peer-to-peer connection system), but you couldn't connect with a regular TCP or WebSocket client, only with a client that also uses the WebRTC data channel protocol.

[Floh]

typo: "Emscripten's TCP API" should better be "Emscripten socket API".

[Sam Clegg]

On Mon, Oct 10, 2022 at 4:22 AM Floh <flo...@gmail.com> wrote:

I might be wrong but I don't think that's possible. First, you can't expose a TCP-compatible socket in browsers (Emscripten's TCP API is an emulation wrapper over WebSockets, which are not protocol-compatible with 'raw' TCP).

I believe it can be done, but it requires running a proxy server on your webserver.  See  https://emscripten.org/docs/porting/networking.html#full-posix-sockets-over-websocket-proxy-server.

Aside from those docs, you might want to look at the test code that we have for `-sPROXY_POSIX_SOCKETS`.     See `test_posix_proxy_sockets` in `test/test_sockets.py`.  

A word of warning: I'm not sure how much testing we have for this mode in terms of actual usage in production, so be prepared for some rough edges, and perhaps then need to write some patches.

WebSocket in the browser can only implement a client interface (e.g. it cannot accept incoming connections, only connect to a 'native' WebSocket server).

WebRTC data channels might allow to implement something that looks like a server running in a browser (because it's a peer-to-peer connection system), but you couldn't connect with a regular TCP or WebSocket client, only with a client that also uses the WebRTC data channel protocol.

On Saturday, 8 October 2022 at 17:00:21 UTC+2 aitha...@gmail.com wrote:

Could anyone provide a sample code for creating a socket server code that can also work from web browsers and accept incoming connections?

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[Aitha Tarun]

Ok thanks for the reply