feat: Allow option publicServerURL to be set dynamically as async function

spec/index.spec.js

@@ -615,6 +615,17 @@ describe('server', () => {
     expect(config.masterKeyCache.expiresAt.getTime()).toBeGreaterThan(Date.now());
   });
 
+  it('should load publicServerURL', async () => {
+    await reconfigureServer({
+      publicServerURL: () => 'https://myserver.com/1',
+    });
+
+    await new Parse.Object('TestObject').save();
+
+    const config = Config.get(Parse.applicationId);
+    expect(config.publicServerURL).toEqual('https://myserver.com/1');
+  });
+
   it('should not reload if ttl is not set', async () => {
     const masterKeySpy = jasmine.createSpy().and.returnValue(Promise.resolve('initialMasterKey'));
 

src/Config.js

@@ -32,6 +32,7 @@ function removeTrailingSlash(str) {
   return str;
 }
 
+const asyncKeys = ['publicServerURL'];
 export class Config {
   static get(applicationId: string, mount: string) {
     const cacheInfo = AppCache.get(applicationId);
@@ -56,9 +57,33 @@ export class Config {
     return config;
   }
 
+  async loadKeys() {
+    const asyncKeys = ['publicServerURL'];
+
+    await Promise.all(
+      asyncKeys.map(async key => {
+        if (typeof this[`_${key}`] === 'function') {
+          this[key] = await this[`_${key}`]();
+        }
+      })
+    );
+
+    Config.put(this);
+  }
+
+  static transformConfiguration(serverConfiguration) {
+    for (const key of Object.keys(serverConfiguration)) {
+      if (asyncKeys.includes(key) && typeof serverConfiguration[key] === 'function') {
+        serverConfiguration[`_${key}`] = serverConfiguration[key];
+        delete serverConfiguration[key];
+      }
+    }
+  }
+
   static put(serverConfiguration) {
     Config.validateOptions(serverConfiguration);
     Config.validateControllers(serverConfiguration);
+    Config.transformConfiguration(serverConfiguration);
     AppCache.put(serverConfiguration.appId, serverConfiguration);
     Config.setupPasswordValidator(serverConfiguration.passwordPolicy);
     return serverConfiguration;
@@ -116,7 +141,11 @@ export class Config {
     }
 
     if (publicServerURL) {
-      if (!publicServerURL.startsWith('http://') && !publicServerURL.startsWith('https://')) {
+      if (
+        typeof publicServerURL !== 'function' &&
+        !publicServerURL.startsWith('http://') &&
+        !publicServerURL.startsWith('https://')
+      ) {
         throw 'publicServerURL should be a valid HTTPS URL starting with https://';
       }
     }
@@ -757,7 +786,6 @@ export class Config {
     return this.masterKey;
   }
 
-
   // TODO: Remove this function once PagesRouter replaces the PublicAPIRouter;
   // the (default) endpoint has to be defined in PagesRouter only.
   get pagesEndpoint() {

src/middlewares.js

@@ -213,6 +213,7 @@ export async function handleParseHeaders(req, res, next) {
     });
     return;
   }
+  await config.loadKeys();
 
   info.app = AppCache.get(info.appId);
   req.config = config;

types/Options/index.d.ts

@@ -85,7 +85,7 @@ export interface ParseServerOptions {
     cacheAdapter?: Adapter<CacheAdapter>;
     emailAdapter?: Adapter<MailAdapter>;
     encodeParseObjectInCloudFunction?: boolean;
-    publicServerURL?: string;
+    publicServerURL?: string | (() => string) | Promise<string>;
     pages?: PagesOptions;
     customPages?: CustomPagesOptions;
     liveQuery?: LiveQueryOptions;