Add readme

Author: anxolin

service/README.md

@@ -0,0 +1,23 @@
+## Webhook for Upptime
+
+This is a webhook for Upptime to notify the Telegram chat.
+
+## Test the webhook
+
+Assuming the [.upptimerc.yml](../.upptimerc.yml) is configured with a site whose name starts with "TEST - Intentional Failure", you can test the webhook with the following command:
+
+```bash
+ curl -X POST "https://uptime-periphery.vercel.app/api/notifyRouter?key=<ROUTER_SECRET>" \
+  -H "content-type: application/json" \
+  -d '{"site":"TEST - Intentional Failure","status":"down"}'
+```
+
+### How to add a new notification channel
+If there's a site whose status needs to be reported to a new channel. 
+
+1. Create a new Telegram channel for the notifications. Add anyone who needs to be notified to the channel.
+2. Add the Telegram Bot to that channel. Write anything in that channel (relevant for next step).
+3. Get the Telegram Chat ID of the channel by checking the result of this https://api.telegram.org/bot<TELEGRAM_BOT_TOKEN>/getUpdates. Make sure you add the telegram bot token to the URL. 
+4. Create a new site. Make sure the name starts with the a given text (let's call this the `prefix`).
+5. Add the `prefix` to the `sitePrefixToTelegramId` record in the [notifyRouter.ts](api/notifyRouter.ts) file, and map it to the Telegram Chat ID you got in step 2.
+6. Deploy the changes to the Vercel app.

service/api/notifyRouter.ts

@@ -66,7 +66,7 @@ export default {
       }
 
       // Map by endpoint name prefix to Telegram chat ID
-      const NAME_PREFIX_TO_TELEGRAM_CHAT_ID: Record<
+      const sitePrefixToTelegramId: Record<
         string,
         string | string[] | undefined
       > = {
@@ -76,7 +76,7 @@ export default {
 
       const url = new URL(request.url);
       if (url.searchParams.get("key") !== routerSecret)
-        return new Response("unauthorized", { status: 401 });
+        return new Response("Not Authorized", { status: 401 });
 
       const payload = await request.json().catch(() => ({} as any));
       const textPayload =
@@ -89,8 +89,8 @@ export default {
         /(^|>)\s*(?<name>[^<(]+)\s*\(/.exec(textPayload)?.groups?.name ||
         "Unknown Site";
 
-      const match = Object.entries(NAME_PREFIX_TO_TELEGRAM_CHAT_ID).find(
-        ([k]) => siteName.startsWith(k)
+      const match = Object.entries(sitePrefixToTelegramId).find(([k]) =>
+        siteName.startsWith(k)
       )?.[1];
 
       // If no matching route found, skip notification silently