Cloudflare Worker Fail2Ban Discord Webhook

readme.md

index.js is the Worker file

wrangler.toml is the Wrangler file that holds your variables

fail2banaction.conf is the action you can add to Fail2Ban

fail2banaction.conf

[Definition]
actionstart = curl -d '{"content": "Fail2ban has started."}' -H "Content-Type: application/json" -X POST "https://yourdiscordwebhook.url/"
actionstop = curl -d '{"content": "Fail2ban has stopped."}' -H "Content-Type: application/json" -X POST "https://yourdiscordwebhook.url/"
actioncheck =
actionban = curl -d '{"ip": "`<ip>`", "failures": "`<failures>`", "type": "ban"}' -H "Content-Type: application/json" -H "cf-webhook-auth: your-secret-key" -X POST "https://your.worker.workers.dev/"
actionunban = curl -d '{"ip": "`<ip>`", "failures": "null", "type": "unban"}' -H "Content-Type: application/json" -H "cf-webhook-auth: your-secret-key" -X POST "https://your.worker.workers.dev/"

index.js

addEventListener("fetch", (event) => {
  event.respondWith(handleRequest(event.request));
});

async function handleRequest(request) {
  const headers = request.headers;

  if (headers.get("cf-webhook-auth") !== WEBHOOK_SECRET) {
    return new Response(":(", {
      headers: { "content-type": "text/plain" },
      status: 401,
    });
  }

  let incReq = await request.json();

  console.log(incReq);

  let dataJSON = {};
  let init = {};
  let response;

  switch (incReq.type) {
    case "ban":
      dataJSON = {
        username: "Fail2Ban Bans",
        avatar_url:
          "https://domoticproject.com/wp-content/uploads/2018/06/fail2ban-logo.jpg",
        content: "",
        embeds: [
          {
            title: `\`${incReq.ip}\``,
            color: 3840,
            description: "Banned",
            timestamp: "",
            author: {
              name: "",
            },
            image: {},
            thumbnail: {},
            footer: {},
            fields: [
              {
                name: "Failures",
                value: incReq.failures,
                inline: true,
              },
              {
                name: "Time",
                value: "36 hours",
                inline: true,
              },
            ],
          },
        ],
        components: [],
      };
      init = {
        body: JSON.stringify(dataJSON),
        method: "POST",
        headers: {
          "content-type": "application/json;charset=UTF-8",
        },
      };

      response = await fetch(WEBHOOK_URL, init);
      return new Response(":)", {
        headers: { "content-type": "text/plain" },
      });
    case "unban":
      dataJSON = {
        username: "Fail2Ban Bans",
        avatar_url:
          "https://domoticproject.com/wp-content/uploads/2018/06/fail2ban-logo.jpg",
        content: "",
        embeds: [
          {
            title: `\`${incReq.ip}\``,
            color: 3840,
            description: "Unbanned",
            timestamp: "",
            author: {
              name: "",
            },
            image: {},
            thumbnail: {},
            footer: {},
            fields: [],
          },
        ],
        components: [],
      };

      init = {
        body: JSON.stringify(dataJSON),
        method: "POST",
        headers: {
          "content-type": "application/json;charset=UTF-8",
        },
      };

      response = await fetch(WEBHOOK_URL, init);
      return new Response(":)", {
        headers: { "content-type": "text/plain" },
      });
    default:
      return new Response(":(", {
        headers: { "content-type": "text/plain" },
      });
  }

  return new Response(":)", {
    headers: { "content-type": "text/plain" },
  });
}

wrangler.toml

[vars]
WEBHOOK_SECRET = "your-secret-key"
WEBHOOK_URL = "https://yourdiscordwebhook.url/"