Moved admin redirect middleware to named file

- moving this middleware because we're about to add a second piece of middleware
- it's easier to see what we have when each middleware is in its own file rather than in one big middleware.js file

core/server/web/admin/app.js

@@ -5,7 +5,7 @@ const config = require('../../../shared/config');
 const constants = require('@tryghost/constants');
 const urlUtils = require('../../../shared/url-utils');
 const shared = require('../shared');
-const adminMiddleware = require('./middleware');
+const redirectAdminUrls = require('./middleware/redirect-admin-urls');
 
 module.exports = function setupAdminApp() {
     debug('Admin setup start');
@@ -39,7 +39,7 @@ module.exports = function setupAdminApp() {
     adminApp.use(shared.middleware.cacheControl('private'));
 
     // Special redirects for the admin (these should have their own cache-control headers)
-    adminApp.use(adminMiddleware);
+    adminApp.use(redirectAdminUrls);
 
     // Finally, routing
     adminApp.get('*', require('./controller'));

core/server/web/admin/middleware/redirect-admin-urls.js

@@ -0,0 +1,15 @@
+const urlUtils = require('../../../../shared/url-utils');
+
+function redirectAdminUrls(req, res, next) {
+    const subdir = urlUtils.getSubdir();
+    const ghostPathRegex = new RegExp(`^${subdir}/ghost/(.+)`);
+    const ghostPathMatch = req.originalUrl.match(ghostPathRegex);
+
+    if (ghostPathMatch) {
+        return res.redirect(urlUtils.urlJoin(urlUtils.urlFor('admin'), '#', ghostPathMatch[1]));
+    }
+
+    next();
+}
+
+module.exports = redirectAdminUrls;

test/unit/server/web/admin/middleware.test.js

@@ -2,7 +2,7 @@ const should = require('should');
 const sinon = require('sinon');
 
 // Thing we are testing
-const redirectAdminUrls = require('../../../../../core/server/web/admin/middleware')[0];
+const redirectAdminUrls = require('../../../../../core/server/web/admin/middleware/redirect-admin-urls');
 
 describe('Admin App', function () {
     afterEach(function () {