Display a PDF file in API Response

Setting Content-Disposition to inline we can display PDF files in API responses instead of downloading.

import { readFile } from 'fs/promises'
import { join } from 'path'

export async function GET(request: Request, { params }: { params: { fileName: string } }) {
  try {
    const filesPath = join(process.cwd(), params.fileName)
    const fileBuffer = await readFile(filesPath)

    return new Response(fileBuffer, {
      'Content-Type': 'application/pdf',
      'Content-Disposition': 'inline'
    })
  } catch (error) {
    return new Response(null, {
      status: 500
    })
  }
}

Note: The API response display depends to the server configuration.