Can't find a way to return a pdf binary

Sorting

• I’m submitting a …

  • bug report
  • feature request
  • support request

• I confirm that I

  • used the search to make sure that a similar issue hasn’t already been submit

Expected Behavior

I’d like to return a PDF from an endpoint and have the Swagger UI reflect the Media Type for that endpoint is " application/pdf".

"/document": {
  "get": {
    "operationId": "Get",
    "responses": {
      "200": {
        "description": "Ok",
        "content": {
          "`application/pdf`": {
            "schema": {
              "type": "string",
              "format": "byte"
            }
          }
        }
      }
    },
  }
}

ℹ️I don’t know swagger spec very well so I’m just guessing above that I’d like content to be application/pdf

Current Behavior

I’ve tried a plain return, e.g. the controller looks like this:

  @Get("/")
  public async getDocument(
  ): Promise<Readable> {
    const buffer = Buffer.from(readFileSync(join(__dirname, "minimal.pdf")));
    return Readable.from(buffer);
  }

This works ✅, but in Swagger UI the Media Type is application/json ❌

I’ve also tried using a TsoaResponse pattern, like this:

  @Get("/")
  public async getDocument(
    @Res() res: TsoaResponse<200, Readable, { "content-type": "application/pdf" }>
  ): Promise<void> {
    const buffer = Buffer.from(readFileSync(join(__dirname, "minimal.pdf")));
    await res(200, Readable.from(buffer), {
      "content-type": "application/pdf",
    });
  }

This also works ✅, but the Swagger UI says application/json ❌ the UI show two responses: One 200, and one 204 (b/c of the void return) ❌

"/documents": {
  "get": {
    "operationId": "Get",
    "responses": {
      "200": {
        "description": "",
        "content": {
          "application/json": {
            "schema": {
              "type": "string",
              "format": "byte"
            }
          }
        },
        "headers": {
          "content-type": {
            "schema": {
              "type": "string",
              "enum": [
                  "application/pdf"
              ],
              "nullable": false
            },
            "required": true
          }
        }
      },
      "204": {
        "description": "No content"
      }
    },
  }
}

Steps to Reproduce

Download this example pdf file: https://brendanzagaeski.appspot.com/minimal.pdf

Add this route:

import { Readable } from "stream";
import {
  Controller,
  Get,
  Route,
} from "tsoa";


@Route("document")
export class DocumentController extends Controller {
  @Get("/1") public async getDocument1(
  ): Promise<Readable> {
    const pdfBuffer = Buffer.from(readFileSync(join(__dirname, "minimal.pdf")))
    return Readable.from(buffer);
  }
}

@Route('document')
export class DocumentController extends Controller {
  @Get('/2')
  public async getDocument2(@Res() res: TsoaResponse<200, Readable, { 'content-type': 'application/pdf' }>): Promise<void> {
    const pdfBuffer = Buffer.from(readFileSync(join(__dirname, 'minimal.pdf')))
    return Readable.from(buffer)
  }
}

Context (Environment)

Version of the library: tsoa@3.11.2 Version of NodeJS: v16.1.0

• Confirm you were using yarn not npm: [😬] (I’m using pnpm, hope that’s not a problem!)

Detailed Description

I’m too new to TSOA + OpenAPI to make a truly specific proposal, but I think I expected either a content-type decorator or some way to use TsoaResponse to specify that this endpoint’s only response is a PDF binary.

And thanks for making tsoa available!

[WoH]

Sounds like this duplicates #968?

Yes, that’s how we should support it.

[Scarbous]

I use tsoa with express.

The express router from tsoa calls pipe if the Object has the right properties. https://github.com/lukeautry/tsoa/blob/master/packages/cli/src/routeGeneration/templates/express.hbs#L210

My current solution is to an Object like:

this.setHeader('Content-type', 'application/pdf');

return {
  readable: true,
  _read: () => { },
  pipe: (res: Response) => { res.end(buffer, 'binary') }
};