E.g., https://t.me/s/energieprijzen/9. It should be “from 19:00 until 19:59” instead of ”from 18:00 until 18:59,” and so on.

Maybe this is happening because the time is shown in UTC? We should also audit other parts of the code where dates and times come into play.

It'd be nice if the bot also sent a chart to make the data available in a different way that might be easier to scan, depending on context. I've been experimenting a bit with Seaborn, and I like what I've been able to do with it relatively quickly, although it's nowhere near as pretty as I'd like it to be, and it would be quite a challenge to use it from Go.

I was researching WebAssembly to hopefully be able to run the bot on
Cloudflare Workers. However, sadly I never even got to the point where I could run it
anywhere (and I'm not blaming anyone but myself). This document serves as a log of my journey.

Installing wasmtime and building the bot for WebAssembly is a piece of cake...

curl https://wasmtime.dev/install.sh -sSf | bash
GOOS=wasip1 GOARCH=wasm go build -o main.wasm cmd/bot/main.go

...but running it is a different story

wasmtime --env ENERGIEPRIJZEN_BOT_TOKEN=somevalue --env ENERGIEPRIJZEN_BOT_CHAT_ID=somevalue main.wasm

2023/11/11 14:35:58 main.go:52: Get "https://api.energyzero.nl/v1/energyprices?fromDate=2023-11-11T22%3A00%3A00Z&inclBtw=true&interval=4&tillDate=2023-11-12T21%3A59%3A59.999Z&usageType=1": dial tcp: lookup api.energyzero.nl on [::1]:53: dial udp [::1]:53: Connection refused

Side-stepping the DNS issue

Hard-coding the/an IP address also doesn't work:

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	const ip = `93.184.216.34` // example.com

	req, err := http.NewRequest("GET", "http://"+ip, nil)
	if err != nil {
		panic(err)
	}
	req.Host = "example.com"

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer resp.Body.Close()

	b, err := io.ReadAll(resp.Body)
	if err != nil {
		panic(err)
	}

	fmt.Println(string(b))
}

panic: Get "http://93.184.216.34": dial tcp 93.184.216.34:80: Connection refused

goroutine 1 [running]:
main.main()
        /workspaces/energieprijzen/main.go:20 +0x2e

stealthrocket/net to the rescue?

There's stealthrocket/net, which is mentioned in a
post on the Go blog, but it doesn't seem to work for my use case:

import (
	// everything is the same as in the minimal reproducible example, except I've added this import:
	_ "github.com/stealthrocket/net/http"
)

Error: failed to run main module `main.wasm`

Caused by:
    0: failed to instantiate "main.wasm"
    1: unknown import: `wasi_snapshot_preview1::sock_open` has not been defined

The future is looking bright

My WebAssembly adventure ends here for now, but the future is looking bright. I found
the WASI HTTP proposal, which is currently in phase 2 of 5. Fingers crossed!

The app shows a graph of the energy rates, but it does not include some additional charges that affect the final price:

Please note that the rates in the chart do not include purchase costs, energy tax, Sustainable Energy Surcharge, and the regional surcharge for gas.

These charges are thus also missing from the prices posted to the channel. The missing charges are:

I don’t know whether the energy price and each of the extra charges are taxed individually (this table assumes so). That’s something I’ll have to look into. That doesn’t matter, as $ax + bx + cx = (a + b + c) x$. Hooray for math making my life easier for once.

https://jpmens.net/2021/04/18/storing-passwords-in-macos-keychain/ ^archived

This saves a few MBs, but it makes debugging harder. It could also make the Repl load faster and make downloading updates faster, which is always nice.

https://github.com/heyajulia/drmhbot/blob/main/.github/workflows/tidy-sources.yml

https://github.com/nektos/act

Because there’s much less variation, it would probably be enough to list the highest, lowest, and average price.

https://pkg.go.dev/embed

• Compare tomorrow's average to today's (and last week's, last year's, etc.)
• #20
• Weather forecast? https://pirateweather.net/en/latest/
• "Greenest moment" https://ned.nl
• Predict the future??? 🤯⚡🔮🤔

The format string for displaying dates in the application is currently set to "Monday _2 January 2006". This causes dates with a single-digit day to have an extra space before the day number, such as "Monday 9 January 2006". The solution is to change the format string to "Monday 2 January 2006".

https://github.com/spf13/cobra
https://github.com/spf13/viper

• remove need for CREDENTIALS_DIRECTORY env var
• update README
• address code TODOs
• move to Fly.io

A message will only be sent if you're logged in. We should convert the launch agent to a launch daemon to fix this.

• How do I set a task to run every so often? - Stack Overflow
• Creating Launch Daemons and Agents
• What are the differences between LaunchAgents and LaunchDaemons? - Ask Different

sendMessage → entities → {"type": "expandable_blockquote", … }

it seems a little challenging, but it could be a good thing to do.