StreamableFileOptions

Kind: Interface

Source: packages/common/file-stream/interfaces/streamable-options.interface.ts

Part of: Common

Options for StreamableFile

StreamableFileOptions configures HTTP response metadata for a StreamableFile. It defines the file MIME type, optional content disposition header value(s), and content length so clients can correctly handle streamed file responses.

Properties

Diagram

mermaid
graph LR
  A[File stream or buffer] --> B[StreamableFile]
  C[StreamableFileOptions] --> B
  C --> D[type: Content-Type]
  C --> E[disposition: Content-Disposition]
  C --> F[length: Content-Length]
  B --> G[HTTP response]

Usage

ts
import { Controller, Get, StreamableFile } from '@nestjs/common';
import { createReadStream } from 'node:fs';
import { join } from 'node:path';
import type { StreamableFileOptions } from '@nestjs/common';

@Controller('reports')
export class ReportsController {
  @Get('download')
  download(): StreamableFile {
    const filePath = join(process.cwd(), 'reports', 'monthly-report.pdf');

    const options: StreamableFileOptions = {
      type: 'application/pdf',
      disposition: 'attachment; filename="monthly-report.pdf"',
      length: 1024 * 256,
    };

    return new StreamableFile(createReadStream(filePath), options);
  }
}

AI Coding Instructions

• Set type to a valid MIME type so browsers and API clients interpret the streamed content correctly.
• Use disposition with attachment to force downloads, or inline when the file should render in the browser.
• Provide length when known to enable an accurate Content-Length response header.
• Ensure the declared length matches the actual stream or buffer size; incorrect values can cause incomplete downloads or hanging clients.
• Pass these options directly to StreamableFile when returning files from NestJS controllers.