Webhook notifier (#380)

Generic webhook notifier

---------

Co-authored-by: charlocharlie <[email protected]>

Readme.md

@@ -97,6 +97,15 @@ The config file is stored in the mounted `/usr/app/config` volume and can be nam
         "priority": "urgent",
         "token": "tk_mytoken"
     },
+    {
+      "type":"webhook",
+      //url of your webhook server
+      "url":"https://webhook.site/my_uuid",
+      //Optional headers
+      "headers": {
+         "Authentication": "Bearer 123456"
+      }
+    },
   ],
 }
 ```

src/common/config/classes.ts

@@ -38,6 +38,7 @@ export enum NotificationType {
   HOMEASSISTANT = 'homeassistant',
   BARK = 'bark',
   NTFY = 'ntfy',
+  WEBHOOK = 'webhook',
 }
 
 /**
@@ -497,6 +498,34 @@ export class BarkConfig extends NotifierConfig {
   }
 }
 
+/**
+ * Sends a POST request with the notification contents in the body to a [webhook](https://en.wikipedia.org/wiki/Webhook) URL
+ */
+export class WebhookConfig extends NotifierConfig {
+  /**
+   * Webhook URL
+   * @env WEBHOOK_URL
+   */
+  @IsUrl({ require_tld: false })
+  url: string;
+
+  /**
+   * A key-value pair object to pass into the POST request headers
+   * @example { Authorization: "Bearer ABCD" }
+   * @env WEBHOOK_HEADERS (stringified JSON)
+   */
+  @IsObject()
+  @IsOptional()
+  headers: Record<string, string> | undefined;
+
+  /**
+   * @ignore
+   */
+  constructor() {
+    super(NotificationType.WEBHOOK);
+  }
+}
+
 export type AnyNotifierConfig =
   | EmailConfig
   | DiscordConfig
@@ -508,7 +537,8 @@ export type AnyNotifierConfig =
   | SlackConfig
   | HomeassistantConfig
   | BarkConfig
-  | NtfyConfig;
+  | NtfyConfig
+  | WebhookConfig;
 
 const notifierSubtypes: {
   value: ClassConstructor<NotifierConfig>;
@@ -525,6 +555,7 @@ const notifierSubtypes: {
   { value: HomeassistantConfig, name: NotificationType.HOMEASSISTANT },
   { value: BarkConfig, name: NotificationType.BARK },
   { value: NtfyConfig, name: NotificationType.NTFY },
+  { value: WebhookConfig, name: NotificationType.WEBHOOK },
 ];
 
 export class WebPortalConfig {
@@ -1135,6 +1166,20 @@ export class AppConfig {
       }
     }
 
+    // Use environment variables to fill webhook notification config if present
+    const { WEBHOOK_URL, WEBHOOK_HEADERS } = process.env;
+    if (WEBHOOK_URL) {
+      const webhook = new WebhookConfig();
+      webhook.url = WEBHOOK_URL;
+      webhook.headers = WEBHOOK_HEADERS ? JSON.parse(WEBHOOK_HEADERS) : undefined;
+      if (!this.notifiers) {
+        this.notifiers = [];
+      }
+      if (!this.notifiers.some((notifConfig) => notifConfig instanceof WebhookConfig)) {
+        this.notifiers.push(webhook);
+      }
+    }
+
     // Use environment variables to fill webPortalConfig if present
     const { BASE_URL, SERVER_PORT } = process.env;
     if (BASE_URL) {

src/notifiers/index.ts

@@ -10,3 +10,4 @@ export * from './slack';
 export * from './bark';
 export * from './ntfy';
 export * from './homeassistant';
+export * from './webhook';

src/notifiers/webhook.ts

@@ -0,0 +1,41 @@
+import axios from 'axios';
+import logger from '../common/logger';
+import { NotifierService } from './notifier-service';
+import { NotificationReason } from '../interfaces/notification-reason';
+import { WebhookConfig } from '../common/config';
+
+export class WebhookNotifier extends NotifierService {
+  private config: WebhookConfig;
+
+  constructor(config: WebhookConfig) {
+    super();
+    this.config = config;
+  }
+
+  async sendNotification(account: string, reason: NotificationReason, url?: string): Promise<void> {
+    const L = logger.child({ user: account, reason });
+    L.trace('Sending webhook notification');
+
+    try {
+      await axios.post(
+        this.config.url,
+        {
+          account,
+          reason,
+          url,
+        },
+        {
+          responseType: 'json',
+          headers: this.config.headers,
+        }
+      );
+    } catch (err) {
+      L.error(err);
+      L.error(
+        { webhookConfig: this.config },
+        'Error sending webhook message. Please check your configuration'
+      );
+      throw err;
+    }
+  }
+}

src/notify.ts

@@ -10,6 +10,7 @@ import {
   NtfyNotifier,
   PushoverNotifier,
   HomeassistantNotifier,
+  WebhookNotifier,
 } from './notifiers';
 import {
   config,
@@ -25,6 +26,7 @@ import {
   NtfyConfig,
   HomeassistantConfig,
   BarkConfig,
+  WebhookConfig,
 } from './common/config';
 import L from './common/logger';
 import { NotificationReason } from './interfaces/notification-reason';
@@ -73,6 +75,8 @@ export async function sendNotification(
         return new BarkNotifier(notifierConfig as BarkConfig);
       case NotificationType.NTFY:
         return new NtfyNotifier(notifierConfig as NtfyConfig);
+      case NotificationType.WEBHOOK:
+        return new WebhookNotifier(notifierConfig as WebhookConfig);
       default:
         throw new Error(`Unexpected notifier config: ${notifierConfig.type}`);
     }