Feature/add proxy route to FetchService (#7153)

* Add proxy route to FetchService

* Update changelog

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+
+- Added support for routing outgoing requests through a per-domain proxy via the `PROXY_ROUTES` setting in the `FetchService`
+
 ## 3.18.0 - 2026-06-28
 
 ### Added

apps/api/src/services/fetch/fetch.service.ts

@@ -4,6 +4,7 @@ import {
   PROPERTY_API_KEY_OPENROUTER,
   PROPERTY_OPENROUTER_MODEL,
   PROPERTY_OPENROUTER_MODEL_WEB_FETCH,
+  PROPERTY_PROXY_ROUTES,
   PROPERTY_WEB_FETCH_ROUTES
 } from '@ghostfolio/common/config';
 
@@ -12,6 +13,7 @@ import { createOpenRouter } from '@openrouter/ai-sdk-provider';
 import { generateText, jsonSchema, tool } from 'ai';
 import ms from 'ms';
 
+import { ProxyRoute } from './interfaces/proxy-route.interface';
 import { WebFetchRoute } from './interfaces/web-fetch-route.interface';
 
 @Injectable()
@@ -21,11 +23,17 @@ export class FetchService implements OnModuleInit {
   private static readonly REDACTED_QUERY_PARAM_NAMES = ['apikey', 'api_token'];
   private static readonly WEB_FETCH_TIMEOUT = ms('30 seconds');
 
+  private proxyRoutes: ProxyRoute[] = [];
   private webFetchRoutes: WebFetchRoute[] = [];
 
   public constructor(private readonly propertyService: PropertyService) {}
 
   public async onModuleInit() {
+    this.proxyRoutes =
+      (await this.propertyService.getByKey<ProxyRoute[]>(
+        PROPERTY_PROXY_ROUTES
+      )) ?? [];
+
     this.webFetchRoutes =
       (await this.propertyService.getByKey<WebFetchRoute[]>(
         PROPERTY_WEB_FETCH_ROUTES
@@ -59,8 +67,10 @@ export class FetchService implements OnModuleInit {
       }
     }
 
+    const proxiedInput = this.applyProxyRoute(input);
+
     try {
-      return await globalThis.fetch(input, init);
+      return await globalThis.fetch(proxiedInput, init);
     } catch (error) {
       if (error instanceof Error) {
         this.logger.error(
@@ -171,18 +181,73 @@ export class FetchService implements OnModuleInit {
     }
   }
 
+  /**
+   * Rewrites the origin (protocol, host and port) of a request when its domain
+   * matches a configured {@link ProxyRoute}, preserving path and query. Returns
+   * the input unchanged when no route matches or parsing fails.
+   */
+  private applyProxyRoute(input: RequestInfo | URL): RequestInfo | URL {
+    let requestUrl: URL;
+
+    try {
+      requestUrl = new URL(
+        input instanceof Request ? input.url : input.toString()
+      );
+    } catch {
+      return input;
+    }
+
+    const route = this.proxyRoutes.find(({ domain }) => {
+      return this.hostnameMatchesDomain({
+        domain,
+        hostname: requestUrl.hostname
+      });
+    });
+
+    if (!route) {
+      return input;
+    }
+
+    try {
+      const proxyUrl = new URL(route.url);
+
+      requestUrl.host = proxyUrl.host;
+      requestUrl.protocol = proxyUrl.protocol;
+    } catch {
+      this.logger.warn(
+        `Skipping proxy route for "${route.domain}": invalid url "${route.url}"`
+      );
+
+      return input;
+    }
+
+    return input instanceof Request
+      ? new Request(requestUrl.toString(), input)
+      : requestUrl.toString();
+  }
+
   private getMatchingWebFetchRoute(url: string) {
     try {
       const { hostname } = new URL(url);
 
       return this.webFetchRoutes.find(({ domain }) => {
-        return hostname === domain || hostname.endsWith(`.${domain}`);
+        return this.hostnameMatchesDomain({ domain, hostname });
       });
     } catch {
       return undefined;
     }
   }
 
+  private hostnameMatchesDomain({
+    domain,
+    hostname
+  }: {
+    domain: string;
+    hostname: string;
+  }): boolean {
+    return hostname === domain || hostname.endsWith(`.${domain}`);
+  }
+
   private redactUrl(rawUrl: string): string {
     try {
       const url = new URL(rawUrl);

apps/api/src/services/fetch/interfaces/proxy-route.interface.ts

@@ -0,0 +1,19 @@
+/**
+ * Overrides the origin (protocol, host and port) of outgoing requests for a
+ * given domain.
+ *
+ * Configured via the `PROXY_ROUTES` property as a JSON array, e.g.
+ *
+ * [
+ *   {
+ *     "domain": "example.com",
+ *     "url": "http://example-proxy:8191"
+ *   }
+ * ]
+ *
+ * Matches the domain itself and its subdomains (e.g. `api.example.com`).
+ */
+export interface ProxyRoute {
+  domain: string;
+  url: string;
+}

libs/common/src/lib/config.ts

@@ -259,6 +259,7 @@ export const PROPERTY_IS_READ_ONLY_MODE = 'IS_READ_ONLY_MODE';
 export const PROPERTY_IS_USER_SIGNUP_ENABLED = 'IS_USER_SIGNUP_ENABLED';
 export const PROPERTY_OPENROUTER_MODEL = 'OPENROUTER_MODEL';
 export const PROPERTY_OPENROUTER_MODEL_WEB_FETCH = 'OPENROUTER_MODEL_WEB_FETCH';
+export const PROPERTY_PROXY_ROUTES = 'PROXY_ROUTES';
 export const PROPERTY_REFERRAL_PARTNERS = 'REFERRAL_PARTNERS';
 export const PROPERTY_SLACK_COMMUNITY_USERS = 'SLACK_COMMUNITY_USERS';
 export const PROPERTY_STRIPE_CONFIG = 'STRIPE_CONFIG';