fix: use-proxy-api-url-version-endpoint (#6743)

Author: Zaimwa9

frontend/api/index.js

@@ -208,6 +208,22 @@ app.get('/version', (req, res) => {
   }
 })
 
+if (process.env.FLAGSMITH_PROXY_API_URL) {
+  app.get('/_backend_version', async (req, res) => {
+    try {
+      const response = await fetch(
+        `${process.env.FLAGSMITH_PROXY_API_URL.replace(/\/?$/, '/')}version/`,
+      )
+      const data = await response.json()
+      res.json(data)
+    } catch (err) {
+      // eslint-disable-next-line
+      console.log('Unable to fetch backend version:', err)
+      res.status(502).json({})
+    }
+  })
+}
+
 app.use(bodyParser.json())
 app.use(spm)
 const genericWebsite = (url) => {

frontend/common/services/useBuildVersion.ts

@@ -13,9 +13,13 @@ export const buildVersionService = service
         providesTags: () => [{ id: 'BuildVersion', type: 'BuildVersion' }],
         queryFn: async (args, _, _2, baseQuery) => {
           try {
+            const backendVersionUrl =
+              Project.api === '/api/v1/'
+                ? '/_backend_version'
+                : `${Project.api.replace('api/v1/', '')}version/`
             const [frontendRes, backendRes] = await Promise.all([
-              data.get(`/version/`).catch(() => ({})),
-              data.get(`${Project.api.replace('api/v1/', '')}version/`),
+              data.get(`/version`).catch(() => ({})),
+              data.get(backendVersionUrl),
             ])
 
             const frontend = (frontendRes || {}) as Version['frontend']