fix(common): update file mime package and add param skip magic numbers

Author: Chathula

package-lock.json

@@ -67,7 +67,7 @@
     "express": "5.1.0",
     "fast-json-stringify": "6.0.1",
     "fast-safe-stringify": "2.1.1",
-    "file-type": "20.4.1",
+    "file-type-checker": "1.1.4",
     "iterare": "1.2.1",
     "object-hash": "3.0.0",
     "path-to-regexp": "8.2.0",

package.json

@@ -18,7 +18,7 @@
   },
   "license": "MIT",
   "dependencies": {
-    "file-type": "20.4.1",
+    "file-type-checker": "1.1.4",
     "iterare": "1.2.1",
     "tslib": "2.8.1",
     "uid": "2.0.2"

packages/common/package.json

@@ -1,3 +1,4 @@
+import * as fileTypeChecker from 'file-type-checker';
 import { FileValidator } from './file-validator.interface';
 import { FileTypeValidatorOptions, IFile } from './interfaces';
 
@@ -26,19 +27,24 @@ export class FileTypeValidator extends FileValidator<
       return true;
     }
 
-    if (!file || !file?.buffer || !file?.mimetype) {
+    const isFileValid = !!file && 'mimetype' in file;
+
+    if (this.validationOptions.skipMagicNumbersValidation) {
+      return (
+        isFileValid && !!file.mimetype.match(this.validationOptions.fileType)
+      );
+    }
+
+    if (!isFileValid || !file.buffer) {
       return false;
     }
 
     try {
-      const { fileTypeFromBuffer } = await import('file-type');
-
-      const fileType = await fileTypeFromBuffer(file.buffer);
-      if (!fileType) {
-        return false;
-      }
+      const fileType = fileTypeChecker.detectFile(file.buffer);
 
-      return !!fileType.mime.match(this.validationOptions.fileType);
+      return (
+        !!fileType && !!fileType.mimeType.match(this.validationOptions.fileType)
+      );
     } catch {
       return false;
     }

packages/common/pipes/file/file-type.validator.ts

@@ -6,4 +6,11 @@ export interface IFile {
 
 export type FileTypeValidatorOptions = {
   fileType: string | RegExp;
+
+  /**
+   * If `true`, the validator will skip the magic numbers validation.
+   * This can be useful when you can't identify some files as there are no common magic numbers available for some file types.
+   * @default false
+   */
+  skipMagicNumbersValidation?: boolean;
 };

packages/common/pipes/file/interfaces/file.interface.ts

@@ -144,6 +144,19 @@ describe('FileTypeValidator', () => {
       expect(await fileTypeValidator.isValid(requestFile)).to.equal(true);
     });
 
+    it('should skip magic numbers validation when the skipMagicNumbersValidation is true', async () => {
+      const fileTypeValidator = new FileTypeValidator({
+        fileType: 'image/jpeg',
+        skipMagicNumbersValidation: true,
+      });
+
+      const requestFile = {
+        mimetype: 'image/jpeg',
+      } as IFile;
+
+      expect(await fileTypeValidator.isValid(requestFile)).to.equal(true);
+    });
+
     it('should return false when the file buffer does not match any known type', async () => {
       const fileTypeValidator = new FileTypeValidator({
         fileType: 'unknown/type',

packages/common/test/pipes/file/file-type.validator.spec.ts

@@ -32,6 +32,20 @@ describe('E2E FileTest', () => {
   it('should allow for file uploads that pass validation', async () => {
     return request(app.getHttpServer())
       .post('/file/pass-validation')
+      .attach('file', './resources/nestjs.jpg')
+      .field('name', 'test')
+      .expect(201)
+      .expect({
+        body: {
+          name: 'test',
+        },
+        file: readFileSync('./resources/nestjs.jpg').toString(),
+      });
+  });
+
+  it('should allow for file uploads that pass validation without using magic numbers validation', async () => {
+    return request(app.getHttpServer())
+      .post('/file/pass-validation-skip-magic-numbers-validation')
       .attach('file', './package.json')
       .field('name', 'test')
       .expect(201)

sample/29-file-upload/e2e/app/app.e2e-spec.ts

@@ -36,11 +36,33 @@ export class AppController {
   @UseInterceptors(FileInterceptor('file'))
   @Post('file/pass-validation')
   uploadFileAndPassValidation(
+    @Body() body: SampleDto,
+    @UploadedFile(
+      new ParseFilePipeBuilder()
+        .addFileTypeValidator({
+          fileType: 'jpeg',
+        })
+        .build({
+          fileIsRequired: false,
+        }),
+    )
+    file?: Express.Multer.File,
+  ) {
+    return {
+      body,
+      file: file?.buffer.toString(),
+    };
+  }
+
+  @UseInterceptors(FileInterceptor('file'))
+  @Post('file/pass-validation-skip-magic-numbers-validation')
+  uploadFileAndPassValidationWithoutMagicNumbersValidation(
     @Body() body: SampleDto,
     @UploadedFile(
       new ParseFilePipeBuilder()
         .addFileTypeValidator({
           fileType: 'json',
+          skipMagicNumbersValidation: true,
         })
         .build({
           fileIsRequired: false,