feat: allow passing in of getCurrentPath option

packages/dotcom-middleware-navigation/readme.md

@@ -45,6 +45,14 @@ The middleware accepts the following parameters. All options will be passed alon
 
 Enables fetching hierarchical navigation data for the current path including any parent and child pages. Defaults to `false`.
 
+### `getCurrentPath`
+
+Enables overriding of the default current path logic. Defaults to:
+
+```js
+  (request) => normalizePath(request.get('ft-vanity-url') || request.path)
+```
+
 ### `interval`
 
 See the [FT navigation documentation] for more details.

packages/dotcom-middleware-navigation/src/__test__/navigation.spec.ts

@@ -136,6 +136,43 @@ describe('dotcom-middleware-navigation', () => {
     })
   })
 
+  describe('when handling a request with a custom getCurrentPath', () => {
+
+    beforeEach(() => {
+      instance = subject.init({ getCurrentPath: () => dummyPath })
+    })
+
+    it('executes the provided getCurrentPath function', async () => {
+      request = httpMocks.createRequest({
+        path: '/path/to/page/123',
+        headers: {
+          'ft-vanity-url': '/vanity-url?page=2'
+        }
+      })
+      const dummyPath = '/foo';
+      const instance = subject.init({ getCurrentPath: () => dummyPath })
+
+      await instance(request, response, next)
+
+      expect(FakeNavigation.getSubNavigationFor).toHaveBeenCalledWith(dummyPath)
+    });
+
+    it('allows overriding of how to calculate current path logic', async () => {
+      request = httpMocks.createRequest({
+        path: '/path/to/page/123',
+        headers: {
+          'ft-blocked-url': '/ig-content-test'
+        }
+      })
+
+      const instance = subject.init({ getCurrentPath: (request) => request.get('ft-blocked-url') })
+      await instance(request, response, next)
+
+      expect(FakeNavigation.getSubNavigationFor).toHaveBeenCalledWith('/ig-content-test')
+    })
+
+  });
+
   describe('when something goes wrong', () => {
     beforeEach(() => {
       FakeNavigation.getMenusFor = jest.fn(() => {

packages/dotcom-middleware-navigation/src/navigation.ts

@@ -5,11 +5,13 @@ import handleEdition from './handleEdition'
 import normalizePath from './normalizePath'
 
 type MiddlewareOptions = TNavOptions & {
-  enableSubNavigation?: boolean
+  enableSubNavigation?: boolean,
+  getCurrentPath?: Function
 }
 
 const defaultOptions: MiddlewareOptions = {
-  enableSubNavigation: false
+  enableSubNavigation: false,
+  getCurrentPath: (request) => normalizePath(request.get('ft-vanity-url') || request.path)
 }
 
 export const init = (userOptions: MiddlewareOptions = {}) => {
@@ -26,7 +28,7 @@ export const init = (userOptions: MiddlewareOptions = {}) => {
       // rather than the underlying path, so prefer that when available.
       // <https://github.com/Financial-Times/ft.com-cdn/blob/4841fbf100e1c561a2f6729b9921ec12bb6b837c/src/vcl/next-preflight.vcl#L213-L219>
       // NOTE: Next router sets the vanity header inc. any query string so it must be normalized.
-      const currentPath = normalizePath(request.get('ft-vanity-url') || request.path)
+      const currentPath = options.getCurrentPath(request);
       const currentEdition = handleEdition(request, response)
 
       const [menusData, subNavigationData] = await Promise.all([