wspingpong

Introduction

In this example we try an alternative websocket-implementation: https://github.com/nhooyr/websocket (check there to see more differences with gorilla's and others)

For this example, we simply want to measure latency and it seems this library already provides it:

From the docs at https://pkg.go.dev/nhooyr.io/websocket#Conn.Ping:

Ping sends a ping to the peer and waits for a pong. Use this to measure latency or ensure the peer is responsive. Ping must be called concurrently with Reader as it does not read from the connection but instead waits for a Reader call to read the pong.

TCP Keepalives should suffice for most use cases.

TODO

• A simple custom http-server without a mux
• Separate server in separate cmd (run with go run cmd/wsppsrv/main.go)
• Client app for easy testing (run with go run cmd/wsppclient/main.go)
• Upgrade client-connections to websocket-connections (/openandclosewebsocket-route)
• Store all connected clients and show them all on page refresh
• Add a bubbletea-TUI
• ...

Specs

no mux

It might be a bit contrarian but this example doesn't use a mux or HandleFunc's. We want to focus on websocket-protocol-specifics so we just use r.URL.String() to check the URL in the http.Request.

custom server

We create a custom net/http-server in stead of using the default http.ListenAndServe(...) because (according to Jon Bodner - Learning Go, page 251):

• other libraries might use these http-package-level-variables already and interfere
• we can then set our own timeouts and custom configuration (like middleware)

block favicon

It just pollutes our logging?

Testing with wireshark

Workflow:

• start wireshark with sufficient privileges (and perhaps install a capture-driver) to capture packets on the local loopback interface
• go run cmd/wsppsrv/main.go
• go run cmd/wsppclient/main.go and choose a request to send
• explore the packets in wireshark: