From ecf1ca69a9dafa90ae88499f064c668b6941dd87 Mon Sep 17 00:00:00 2001
From: Hassan_Wari <85742599+hassan254-prog@users.noreply.github.com>
Date: Fri, 9 Aug 2024 10:54:11 +0300
Subject: [PATCH] feat(proxy): add fallback to proxy base_url (#1873)

## Describe your changes
Continuing from this,
https://github.com/NangoHQ/nango/pull/1770#discussion_r1526495126. We
need to have a fallback incase `api_base_url_for_customer` field is not
populated in the connection configuration. I have also added a unit test
for this..

---------

Co-authored-by: Khaliq <khaliq@nango.dev>
---
 packages/shared/lib/services/proxy.service.ts | 15 ++++++-
 .../lib/services/proxy.service.unit.test.ts   | 40 +++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/packages/shared/lib/services/proxy.service.ts b/packages/shared/lib/services/proxy.service.ts
index 33bb83393f..cdb3f1c5c4 100644
--- a/packages/shared/lib/services/proxy.service.ts
+++ b/packages/shared/lib/services/proxy.service.ts
@@ -386,7 +386,20 @@ class ProxyService {
         const { connection } = config;
         const { template: { proxy: { base_url: templateApiBase } = {} } = {}, endpoint: apiEndpoint } = config;
 
-        const apiBase = config.baseUrlOverride || templateApiBase;
+        let apiBase = config.baseUrlOverride || templateApiBase;
+
+        if (apiBase?.includes('${') && apiBase?.includes('||')) {
+            const connectionConfig = connection.connection_config;
+            const splitApiBase = apiBase.split(/\s*\|\|\s*/);
+
+            if (!connectionConfig) {
+                apiBase = splitApiBase[1];
+            } else {
+                const keyMatch = apiBase.match(/connectionConfig\.(\w+)/);
+                const index = keyMatch && keyMatch[1] && connectionConfig[keyMatch[1]] ? 0 : 1;
+                apiBase = splitApiBase[index]?.trim();
+            }
+        }
 
         const base = apiBase?.substr(-1) === '/' ? apiBase.slice(0, -1) : apiBase;
         let endpoint = apiEndpoint.charAt(0) === '/' ? apiEndpoint.slice(1) : apiEndpoint;
diff --git a/packages/shared/lib/services/proxy.service.unit.test.ts b/packages/shared/lib/services/proxy.service.unit.test.ts
index 2ce3931fcd..1543e0ca57 100644
--- a/packages/shared/lib/services/proxy.service.unit.test.ts
+++ b/packages/shared/lib/services/proxy.service.unit.test.ts
@@ -425,6 +425,46 @@ describe('Proxy service Construct URL Tests', () => {
         expect(url).toBe('https://myinstanceurl.com/api/test');
     });
 
+    it('Should handle Proxy base URL interpolation where connection configuration param is present', () => {
+        const config = {
+            template: {
+                auth_mode: 'OAUTH2',
+                proxy: {
+                    base_url: '${connectionConfig.api_base_url_for_customer} || https://api.gong.io'
+                }
+            },
+            token: { apiKey: 'sweet-secret-token' },
+            endpoint: '/api/test',
+            connection: {
+                connection_config: { api_base_url_for_customer: 'https://company-17.api.gong.io' }
+            }
+        };
+
+        const url = proxyService.constructUrl(config as unknown as ApplicationConstructedProxyConfiguration);
+
+        expect(url).toBe('https://company-17.api.gong.io/api/test');
+    });
+
+    it('Should handle Proxy base URL interpolation where connection configuration param is absent', () => {
+        const config = {
+            template: {
+                auth_mode: 'OAUTH2',
+                proxy: {
+                    base_url: '${connectionConfig.api_base_url_for_customer}||https://api.gong.io'
+                }
+            },
+            token: { apiKey: 'sweet-secret-token' },
+            endpoint: '/api/test',
+            connection: {
+                environment_id: 1
+            }
+        };
+
+        const url = proxyService.constructUrl(config as unknown as ApplicationConstructedProxyConfiguration);
+
+        expect(url).toBe('https://api.gong.io/api/test');
+    });
+
     it('Should strip away the auth token from the headers', () => {
         const headers = {
             Accept: 'application/json',