MulterOptions

Kind: Interface

Source: packages/platform-express/multer/interfaces/multer-options.interface.ts

Part of: Platform Express

MulterOptions configures how NestJS's Express platform integrates with Multer for handling multipart/form-data uploads. It controls upload destinations, storage engines, upload limits, path preservation, and the default character set used when parsing form data.

Properties

Diagram

mermaid
graph LR
  Client[Multipart Request] --> Interceptor[File Upload Interceptor]
  Interceptor --> Options[MulterOptions]
  Options --> Storage[storage or dest]
  Options --> Limits[limits]
  Options --> Parsing[preservePath and defParamCharset]
  Storage --> Files[Stored Uploaded Files]
  Limits --> Validation[Upload Constraints]

Usage

ts
import { Module } from '@nestjs/common';
import { MulterModule } from '@nestjs/platform-express';
import { diskStorage } from 'multer';
import type { MulterOptions } from '@nestjs/platform-express/multer/interfaces/multer-options.interface';

const multerOptions: MulterOptions = {
  storage: diskStorage({
    destination: './uploads',
    filename: (_request, file, callback) => {
      callback(null, `${Date.now()}-${file.originalname}`);
    },
  }),
  limits: {
    fileSize: 5 * 1024 * 1024, // 5 MB
    files: 3,
  },
  preservePath: false,
  defParamCharset: 'utf8',
};

@Module({
  imports: [MulterModule.register(multerOptions)],
})
export class AppModule {}

AI Coding Instructions

• Prefer storage with a Multer storage engine when filename generation or destination handling requires custom behavior.
• Use dest only for simple disk-based uploads; do not configure both dest and a custom storage engine unless the underlying Multer behavior is explicitly intended.
• Always define limits, especially fileSize and files, to prevent excessive resource consumption from upload requests.
• Keep preservePath disabled unless preserving client-provided directory paths is required and has been reviewed for security implications.
• Configure these options through MulterModule.register() globally or MulterModule.registerAsync() when settings depend on injected configuration.