feat: add allowHeaders to Options (#6044)

* feat: add allowHeaders to Options

This allows developers to use custom headers in their API requests, and they will be accepted by their mounted app.

* refactor: convert allowCrossDomain to generator to add appId in scope

This is necessary as the middleware may run in OPTIONS request that do not contain the appId within the header.

* chore: update Definitions and docs

* fix: update test to use new allowCrossDomain params

* chore: add tests for allowCustomDomain middleware re: allowHeadrs

src/Options/Definitions.js

@@ -17,6 +17,11 @@ module.exports.ParseServerOptions = {
     action: parsers.booleanParser,
     default: true,
   },
+  allowHeaders: {
+    env: 'PARSE_SERVER_ALLOW_HEADERS',
+    help: 'Add headers to Access-Control-Allow-Headers',
+    action: parsers.arrayParser,
+  },
   analyticsAdapter: {
     env: 'PARSE_SERVER_ANALYTICS_ADAPTER',
     help: 'Adapter module for the analytics',

src/Options/docs.js

@@ -2,6 +2,7 @@
  * @interface ParseServerOptions
  * @property {Any} accountLockout account lockout policy for failed login attempts
  * @property {Boolean} allowClientClassCreation Enable (or disable) client class creation, defaults to true
+ * @property {String[]} allowHeaders Add headers to Access-Control-Allow-Headers
  * @property {Adapter<AnalyticsAdapter>} analyticsAdapter Adapter module for the analytics
  * @property {String} appId Your Parse Application ID
  * @property {String} appName Sets the app name

src/Options/index.js

@@ -26,6 +26,8 @@ export interface ParseServerOptions {
   masterKeyIps: ?(string[]);
   /* Sets the app name */
   appName: ?string;
+  /* Add headers to Access-Control-Allow-Headers */
+  allowHeaders: ?(string[]);
   /* Adapter module for the analytics */
   analyticsAdapter: ?Adapter<AnalyticsAdapter>;
   /* Adapter module for the files sub-system */