From fda6664e72bc18b9463f6c46ee73d598f40fb538 Mon Sep 17 00:00:00 2001
From: Luca Becker <luca.becker@me.com>
Date: Sun, 7 Feb 2021 10:08:53 +0100
Subject: [PATCH] feat(platform-express): Allowing pipes for FileInterceptor

https://github.com/nestjs/nest/issues/4752
---
 .../multer/interceptors/file.interceptor.ts   | 17 ++++++++++
 .../interceptors/file.interceptor.spec.ts     | 33 ++++++++++++++++++-
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/packages/platform-express/multer/interceptors/file.interceptor.ts b/packages/platform-express/multer/interceptors/file.interceptor.ts
index 6261c23cb06..b94f1c11038 100644
--- a/packages/platform-express/multer/interceptors/file.interceptor.ts
+++ b/packages/platform-express/multer/interceptors/file.interceptor.ts
@@ -5,6 +5,7 @@ import {
   mixin,
   NestInterceptor,
   Optional,
+  PipeTransform,
   Type,
 } from '@nestjs/common';
 import * as multer from 'multer';
@@ -19,6 +20,7 @@ type MulterInstance = any;
 export function FileInterceptor(
   fieldName: string,
   localOptions?: MulterOptions,
+  ...pipes: (Type<PipeTransform> | PipeTransform)[]
 ): Type<NestInterceptor> {
   class MixinInterceptor implements NestInterceptor {
     protected multer: MulterInstance;
@@ -49,6 +51,21 @@ export function FileInterceptor(
               const error = transformException(err);
               return reject(error);
             }
+
+            if (pipes.length > 0) {
+              const request = ctx.getRequest();
+              request.file = pipes.reduce(
+                (previousFile, Pipe: Type<PipeTransform> | PipeTransform) => {
+                  const pipeInstance: PipeTransform =
+                    typeof Pipe === 'function' ? new Pipe() : Pipe;
+                  return pipeInstance.transform(previousFile, {
+                    type: 'custom',
+                  });
+                },
+                request.file,
+              );
+            }
+
             resolve();
           },
         ),
diff --git a/packages/platform-express/test/multer/interceptors/file.interceptor.spec.ts b/packages/platform-express/test/multer/interceptors/file.interceptor.spec.ts
index 39f003e1465..0a125c1201c 100644
--- a/packages/platform-express/test/multer/interceptors/file.interceptor.spec.ts
+++ b/packages/platform-express/test/multer/interceptors/file.interceptor.spec.ts
@@ -1,10 +1,14 @@
-import { CallHandler } from '@nestjs/common';
+import { CallHandler, PipeTransform } from '@nestjs/common';
 import { ExecutionContextHost } from '@nestjs/core/helpers/execution-context-host';
 import { expect } from 'chai';
 import { of } from 'rxjs';
 import * as sinon from 'sinon';
 import { FileInterceptor } from '../../../multer/interceptors/file.interceptor';
 
+const createFilePipe = (): PipeTransform => ({
+  transform: (): any => undefined,
+});
+
 describe('FileInterceptor', () => {
   it('should return metatype with expected structure', async () => {
     const targetClass = FileInterceptor('file');
@@ -42,5 +46,32 @@ describe('FileInterceptor', () => {
         error => expect(error).to.not.be.undefined,
       );
     });
+    it('should accept pipes and call them', async () => {
+      const fieldName = 'file';
+      const pipe = createFilePipe();
+      const secondPipe = createFilePipe();
+      const myFakeFile: any = {};
+      const transformSpy = sinon.stub(pipe, 'transform').returns(myFakeFile);
+      const secondTransformSpy = sinon
+        .stub(secondPipe, 'transform')
+        .returns(undefined);
+      const target = new (FileInterceptor(
+        fieldName,
+        undefined,
+        pipe,
+        secondPipe,
+      ))();
+      const callback = (req, res, next) => next();
+      sinon.stub((target as any).multer, 'single').returns(callback);
+
+      await target.intercept(
+        new ExecutionContextHost([{ file: myFakeFile }]),
+        handler,
+      );
+
+      expect(transformSpy.called).to.be.true;
+      expect(transformSpy.calledWith(myFakeFile)).to.be.true;
+      expect(secondTransformSpy.called).to.be.true;
+    });
   });
 });