feat: added custom loader option, fixed #7 (thanks @niksoc)

Author: SimonB407

src/admin.module.ts

@@ -61,6 +61,10 @@ export class AdminModule implements OnModuleInit {
           provide: CONFIG_TOKEN,
           useValue: options,
         },
+        options.customLoader ? {
+          provide: AbstractLoader,
+          useClass: options.customLoader,
+        } : serveStaticProvider,
       ],
     }
   }

src/interfaces/admin-module-options.interface.ts

@@ -1,6 +1,9 @@
+import { Type } from '@nestjs/common';
 import { AdminBroOptions, CurrentAdmin } from 'admin-bro';
 import { SessionOptions } from 'express-session';
 
+import { AbstractLoader } from '../loaders/abstract.loader';
+
 import { ExpressFormidableOptions } from './express-formidable-options.interface';
 
 /**
@@ -35,4 +38,9 @@ export type AdminModuleOptions = {
    * something more reliable (i.e. database).
    */
   sessionOptions?: SessionOptions,
+  /**
+   * In order not to use default Express (@admin-bro/express) or Fastify (not yet implemented) loader
+   * you can provide your own implementation of Loader that plugs in AdminBro.
+   */
+  customLoader?: Type<AbstractLoader>,
 }

src/loaders/express.loader.ts

@@ -23,43 +23,64 @@ export class ExpressLoader extends AbstractLoader {
     );
     loadPackage('express-formidable', '@admin-bro/nestjs');
 
+    let router;
+
+    if ('auth' in options) {
+      loadPackage('express-session', '@admin-bro/nestjs');
+      router = adminBroExpressjs.buildAuthenticatedRouter(
+        admin, options.auth, undefined, options.sessionOptions, options.formidableOptions
+      );
+    } else {
+      router = adminBroExpressjs.buildRouter(admin, undefined, options.formidableOptions);
+    }
+
+    app.use(options.adminBroOptions.rootPath, router);
+    this.reorderRoutes(app, options);980
+  }
+
+  private reorderRoutes(app, options) {
     let jsonParser;
     let urlencodedParser;
+    let admin;
 
     // Nestjs uses bodyParser under the hood which is in conflict with admin-bro setup.
     // Due to admin-bro-expressjs usage of formidable we have to move body parser in layer tree after admin-bro init.
     // Notice! This is not documented feature of express, so this may change in the future. We have to keep an eye on it.
     if (app && app._router && app._router.stack) {
-      const jsonParserIndex = app._router.stack.findIndex(layer => layer.name === 'jsonParser');
+      const jsonParserIndex = app._router.stack.findIndex(
+        (layer: { name: string }) => layer.name === 'jsonParser'
+      );
       if (jsonParserIndex >= 0) {
         jsonParser = app._router.stack.splice(jsonParserIndex, 1);
       }
 
-      const urlencodedParserIndex = app._router.stack.findIndex(layer => layer.name === 'urlencodedParser');
+      const urlencodedParserIndex = app._router.stack.findIndex(
+        (layer: { name: string }) => layer.name === 'urlencodedParser'
+      );
       if (urlencodedParserIndex >= 0) {
         urlencodedParser = app._router.stack.splice(urlencodedParserIndex, 1);
       }
-    }
-
-    let router;
 
-    if ('auth' in options) {
-      loadPackage('express-session', '@admin-bro/nestjs');
-      router = adminBroExpressjs.buildAuthenticatedRouter(
-        admin, options.auth, undefined, options.sessionOptions, options.formidableOptions
-      );
-    } else {
-      router = adminBroExpressjs.buildRouter(admin, undefined, options.formidableOptions);
-    }
-
-    app.use(options.adminBroOptions.rootPath, router);
+      const adminIndex = app._router.stack.findIndex((layer: { regexp: RegExp }) =>
+        layer.regexp.toString().includes(options.adminBroOptions.rootPath),
+      )
+      if (adminIndex >= 0) {
+        admin = app._router.stack.splice(adminIndex, 1)
+      }
 
-    if (jsonParser) {
-      app._router.stack.push(...jsonParser);
-    }
+      // if admin-bro-nestjs didn't reorder the middleware
+      // the body parser would have come after corsMiddleware
+      const corsIndex = app._router.stack.findIndex(
+        (layer: { name: string }) => layer.name === 'corsMiddleware',
+      )
 
-    if (urlencodedParser) {
-      app._router.stack.push(...urlencodedParser);
+      app._router.stack.splice(
+        corsIndex >= 0 ? corsIndex + 1 : app._router.stack.length,
+        0,
+        ...admin,
+        ...jsonParser,
+        ...urlencodedParser,
+      )
     }
   }
 }