feat: add /client/env API route for sending client env vars as JSON

shared/types/core.ts

@@ -10,3 +10,20 @@ export interface PrivateFormErrorDto extends ErrorDto {
   isPageFound: true
   formTitle: string
 }
+
+// List of env vars expected from the server that client uses
+export type ClientEnvVars = {
+  isGeneralMaintenance: string
+  isLoginBanner: string
+  siteBannerContent: string
+  adminBannerContent: string
+  logoBucketUrl: string // S3 bucket
+  formsgSdkMode: 'staging' | 'production' | 'development' | 'test'
+  captchaPublicKey: string // Recaptcha
+  sentryConfigUrl: string // Sentry.IO
+  isSPMaintenance: string // Singpass maintenance message
+  isCPMaintenance: string // Corppass maintenance message
+  myInfoBannerContent: string // MyInfo maintenance message
+  GATrackingID: string | null
+  spcpCookieDomain: string // Cookie domain used for removing spcp cookies
+}

src/app/modules/frontend/frontend.controller.ts

@@ -1,11 +1,13 @@
 import ejs from 'ejs'
 import { StatusCodes } from 'http-status-codes'
 
+import { ClientEnvVars } from '../../../../shared/types/core'
 import { createLoggerWithLabel } from '../../config/logger'
 import { createReqMeta } from '../../utils/request'
 import { ControllerHandler } from '../core/core.types'
 
 import { validateGenerateRedirectParams } from './frontend.middlewares'
+import { getClientEnvVars } from './frontend.service'
 
 const logger = createLoggerWithLabel(module)
 
@@ -77,6 +79,17 @@ export const addEnvVarData: ControllerHandler<unknown, { message: string }> = (
   }
 }
 
+/**
+ * Handler for GET /frontend/env endpoint.
+ * @returns the environment variables needed to hydrate the frontend.
+ */
+export const handleGetEnvironment: ControllerHandler<never, ClientEnvVars> = (
+  _req,
+  res,
+) => {
+  return res.json(getClientEnvVars())
+}
+
 /**
  * Handler for GET /frontend/redirect endpoint.
  * @param req - Express request object

src/app/modules/frontend/frontend.routes.ts

@@ -5,6 +5,7 @@ import * as FrontendServerController from './frontend.controller'
 export const FrontendRouter = Router()
 
 /**
+ * @deprecated use routes in src/app/routes/api/v3/client/client.routes.ts instead
  * Generate the templated Javascript code for the frontend to initialise Google Tag Manager
  * Code depends on whether googleAnalyticsFeature.isEnabled
  * @route GET /frontend/datalayer
@@ -17,6 +18,7 @@ FrontendRouter.get(
 )
 
 /**
+ * @deprecated use routes in src/app/routes/api/v3/client/client.routes.ts instead
  * Generate the templated Javascript code with environment variables for the frontend
  * @route GET /frontend/environment
  * @return 200 when code generation is successful
@@ -25,6 +27,7 @@ FrontendRouter.get(
 FrontendRouter.get('/environment', FrontendServerController.addEnvVarData)
 
 /**
+ * @deprecated use routes in src/app/routes/api/v3/client/client.routes.ts instead
  * Generate a json of current activated features
  * @route GET /frontend/features
  * @return json with featureManager.states
@@ -34,6 +37,7 @@ FrontendRouter.get('/environment', FrontendServerController.addEnvVarData)
 FrontendRouter.get('/features', FrontendServerController.showFeaturesStates)
 
 /**
+ * @deprecated use routes in src/app/routes/api/v3/client/client.routes.ts instead
  * Generate the javascript code to redirect to the correct url
  * @route GET /frontend/redirect
  * @return 200 when redirect code is  successful

src/app/modules/frontend/frontend.service.ts

@@ -0,0 +1,24 @@
+import { ClientEnvVars } from '../../../../shared/types/core'
+import config from '../../config/config'
+import { captchaConfig } from '../../config/features/captcha.config'
+import { googleAnalyticsConfig } from '../../config/features/google-analytics.config'
+import { sentryConfig } from '../../config/features/sentry.config'
+import { spcpMyInfoConfig } from '../../config/features/spcp-myinfo.config'
+
+export const getClientEnvVars = (): ClientEnvVars => {
+  return {
+    isGeneralMaintenance: config.isGeneralMaintenance,
+    isLoginBanner: config.isLoginBanner,
+    siteBannerContent: config.siteBannerContent,
+    adminBannerContent: config.adminBannerContent,
+    logoBucketUrl: config.aws.logoBucketUrl, // S3 bucket
+    formsgSdkMode: config.formsgSdkMode,
+    captchaPublicKey: captchaConfig.captchaPublicKey, // Recaptcha
+    sentryConfigUrl: sentryConfig.sentryConfigUrl, // Sentry.IO
+    isSPMaintenance: spcpMyInfoConfig.isSPMaintenance, // Singpass maintenance message
+    isCPMaintenance: spcpMyInfoConfig.isCPMaintenance, // Corppass maintenance message
+    myInfoBannerContent: spcpMyInfoConfig.myInfoBannerContent, // MyInfo maintenance message
+    GATrackingID: googleAnalyticsConfig.GATrackingID,
+    spcpCookieDomain: spcpMyInfoConfig.spcpCookieDomain, // Cookie domain used for removing spcp cookies
+  }
+}

src/app/routes/api/v3/client/client.routes.ts

@@ -24,6 +24,13 @@ ClientRouter.get(
  */
 ClientRouter.get('/environment', FrontendServerController.addEnvVarData)
 
+/**
+ * Retrieve the environment variables for the frontend.
+ * @route GET /api/v3/client/env
+ * @return 200 with environment variables needed for the client
+ */
+ClientRouter.get('/env', FrontendServerController.handleGetEnvironment)
+
 /**
  * Generate a json of current activated features
  * @route GET /api/v3/client/features