feature: Add an option to enable Telegram to work behind a proxy. (#6125)

Co-authored-by: Frank Elsinga <frank@elsinga.de>

server/notification-providers/notification-provider.js

@@ -1,5 +1,6 @@
 const { Liquid } = require("liquidjs");
 const { DOWN } = require("../../src/util");
+const ProxyAgent = require("proxy-agent");
 
 class NotificationProvider {
 
@@ -115,6 +116,22 @@ class NotificationProvider {
 
         throw new Error(msg);
     }
+
+    /**
+     * Returns axios config with proxy agent if proxy env is set.
+     * @param {object} axiosConfig - Axios config containing params
+     * @returns {object} Axios config
+     */
+    getAxiosConfigWithProxy(axiosConfig = {}) {
+        const proxyEnv = process.env.notification_proxy || process.env.NOTIFICATION_PROXY;
+        if (proxyEnv) {
+            const agent = new ProxyAgent(proxyEnv);
+            axiosConfig.httpsAgent = agent;
+            axiosConfig.httpAgent = agent;
+            axiosConfig.proxy = false;
+        }
+        return axiosConfig;
+    }
 }
 
 module.exports = NotificationProvider;