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Making a Discord Vaccine Bot

williambl profile image Will BL ・3 min read

I recently made a Discord bot that tracks the UK vaccine rollout, using Java, JDA, and the coronavirus.data.gov.uk API.

First Ideas

I'd been browsing the excellent UK Coronavirus dashboard, and I saw the 'developers' guide' link.

I gave it a quick look over, saw that it didn't require registering for an API key or anything, and had an idea: make a Discord bot to spread vaccine positivity in my group chats :)

JDA and Java

I've done work on Discord bots for communities using JDA before, so I knew I'd use that for this project just because I had familiarity with it.

Regarding language, I had the option to either use Java or Kotlin - I went with Java just because it tends to be quicker for Gradle to set up a Java project (not having to download the latest Kotlin stdlib), but I do much prefer Kotlin and for most purposes will use that.

First attempts

My first attempt was very basic, and amounted to something similar to this:

private static final String API_URL = "[...]";
private static final Timer TIMER = new Timer();

private static JDA bot;

public static void main(String[] args) {
    try {
        bot = JDABuilder.createDefault(args[0])
                .setActivity(Activity.watching("the vaccine rollout"))
                .build();

        TIMER.scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                checkStats(bot, args[1]);
            }
        }, 2000, 1000 * 60 * 60 * 24);

    } catch (LoginException e) { [...] }
}

private static void checkStats(JDA bot, String channelId) {
    long amount;
    try {
        amount = JsonParser.parseReader(new InputStreamReader(new GZIPInputStream(new URL(API_URL).openStream()))).getAsJsonObject().getAsJsonArray("data").get(0).getAsJsonObject().get("value").getAsLong();
    } catch (IOException e) { [...] }

    channel.sendMessage(":tada: **Good news!**\nThere have now been "+amount+" vaccinations in the UK!").queue();
}
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This worked, but was a bit barebones.

It does three things:

  • sets up a bot with JDA, with the token given from the first command-line argument (JDABuilder.createDefault(args[0]))
  • sets the bot's activity as "watching the vaccine rollout" (setActivity(Activity.watching("the vaccine rollout")))
  • sets a timer, which every 24 hours (1000 * 60 * 60 * 24 milliseconds) checks the vaccination count and sends a message to a channel as given in the second argument (checkStats function)

I took me an hour or so to get to this point. Most of the time was spent trying to work out why the input I was receiving was garbled.

Because I hadn't read this: All API responses are compressed using GZip. The request client must therefore accept GZip encoded content.

RTFM, folks.

One GZIPInputStream later, everything was working! But what else could I do?

Extra features

The next thing I did was percentage calculation, just done by dividing by 680000 (roughly 0.01 times the UK population). There were decimal place mishaps at first:

vaccine bot reporting first as '1%', then '154%', then finally the correct '15%', to reactions of "that's not right", "that's definitely not right", "154%? seems legit to me", and finally "that's better"

But it eventually worked well.

I later added the count as words, which my girlfriend said she could parse better than the numerals:

There have now been 10971047 (that's ten million nine hundred seventy-one thousand forty-seven) vaccinations in the UK! That's 16% of the population!

I used a library called 'tradukisto' to do the work for me. It also supports other languages than English, which is cool.

I also later added a command, ,vaccinebot, to get an immediate count:
the bot being triggered by the ',vaccinebot' command

Conclusion

This was a fun quick project, and it's had an uplifting impact on my friends: people saying 'past the 12 million mark!!' and 'my mum is part of that number :)' as a response to Vaccine Bot

If anyone else wants to run an instance of it, the code is available.

I'm grateful that Public Health England have made the COVID data available via an accessible and documented API, and that the COVID dashboard website exists.

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