nest/sample/29-file-upload

File Upload

This sample demonstrates multipart file uploads with FileInterceptor and file validation with ParseFilePipeBuilder.

Execution

From the repository root:

cd sample/29-file-upload
npm install
npm run start # OR npm run start:dev

Requests

Run the following commands in another terminal from sample/29-file-upload. The --include option displays the HTTP status and response headers.

Upload without validation

curl --include http://localhost:3000/file \
  -F 'file=@./package.json' \
  -F 'name=test'

Expected status: 201 Created. The response contains the form fields in body and the file contents as a string in file.

Upload a file that passes validation

curl --include http://localhost:3000/file/pass-validation \
  -F 'file=@./resources/nestjs.jpg' \
  -F 'name=test'

Expected status: 201 Created. The configured fileType: 'jpeg' matches the JPEG MIME type, image/jpeg. By default, FileTypeValidator detects the type from the file contents; changing a file's extension does not make it valid.

Upload a file that fails validation

curl --include http://localhost:3000/file/fail-validation \
  -F 'file=@./package.json' \
  -F 'name=test'

Expected status: 400 Bad Request. The uploaded JSON file fails file type validation. This endpoint deliberately uses fileType: 'jpg', which does not match image/jpeg, so uploading resources/nestjs.jpg here also fails.

Omit an optional file

The /file/pass-validation endpoint sets fileIsRequired: false, so it also accepts requests without a file:

curl --include http://localhost:3000/file/pass-validation -F 'name=test'

Expected status: 201 Created, with the response below. The file property is omitted when no file is uploaded.

{ "body": { "name": "test" } }

Omit a required file

The /file/fail-validation endpoint requires a file by default:

curl --include http://localhost:3000/file/fail-validation -F 'name=test'

Expected status: 400 Bad Request, with the message File is required.