Apollo-server: File upload receiving buffer instead of promise with createTestClient

[JonathanRoyGagnon]

Calling a resolver using createTestClient and a file gives a buffer instead of a promise like you would normally receiving from a client.

// test.js
it('UPLOAD', async () => {
  const file = fs.readFileSync(path.join(__dirname, './test.txt'))

  const UPLOAD = gql`
    mutation upload($files: [Upload!]!) {
      upload(files: $files) {
        location
      }
    }
  `

  const { mutate } = createTestClient(server)

  const res = await mutate({ query: UPLOAD, variables: { files: [file] } })
})

// resolver.js
  Mutation: {
    async upload (root, { files }) {
      console.log('Files', files)
      const medias = await Promise.all(files.map(async file => {
        const { stream, mimetype } = await file
        console.log('Info', stream, mimetype)
        // ...
      })).catch(console.error)
      return medias
    }
  }

console.log resolver.js
  Files [ <Buffer 49 20 61 6d 20 61 20 74 65 73 74 20 66 69 6c 65> ]
  Info undefined undefined

Is the Upload scalar supported by createTestClient?

[WoLfulus]

I'm also receiving undefined in stream. Did you solve this?

[JonathanRoyGagnon]

No, I had to leave it out until this is fixed

[joemckie]

It feels a little hacky, but I got this to work by doing the following:

import { createReadStream } from 'fs';

const fileName = `${__dirname}/...`;

const response = await mutate({
  mutation: UPLOAD_PRODUCT_IMAGE,
  variables: {
    file: {
      createReadStream: () => createReadStream(fileName),
      filename: 'image.jpg',
      mimetype: 'image/jpeg',
    },
  },
});

Instead of using readFileSync, pass your own createReadStream function that creates a stream with the path to the file you want.

[loremaps]

@joemckie does this still works for you?

I am getting the following error:

 Received: [[GraphQLError: Variable "$file" got invalid value { createReadStream: [function createReadStream], filename: "image.jpg", mimetype: "image/jpeg" }; Expected type Upload. Upload value invalid.]]

Any ideas?

[joemckie]

@loremaps I think I removed this code in a refactor when I moved to NestJS unfortunately so I wouldn't be able to test it out any more 😞

FWIW, I remember this being an issue during the refactor, and I found it was easier to test it by using supertest and using a multipart request

[Nabrok]

@loremaps I am getting the same error as you, did you find a solution?

EDIT: Okay, so digging into it I found graphql-upload expects to receive an instance of the Upload class. I got around it with ...

const fs = require('fs');
const path = require('path');
const Upload = require('graphql-upload/public/Upload');

let test_client;

beforeEach(async () => {
  // Setup test_client
  ...
});

test('upload file', async () => {
  const filename = 'test.txt';
  const file = new Upload();
  file.promise = new Promise(resolve => resolve({
    createReadStream: () => fs.createReadStream(path.join(__dirname, '__fixtures__', filename)),
    filename,
    mimetype: 'text/plain'
  }));
  const upload_file = await test_client.mutate({ query: QUERY, variables: { file } });
  expect(upload_file.errors).toBeUndefined();
});

[glasser]

We are removing the built-in graphql-upload integration in Apollo Server 3 and are also considering removing apollo-server-testing as a standalone package so I am going to close this issue.

createTestClient is a very thin wrapper around server.executeOperation, a function that lets you hook directly in to the Apollo Server request pipeline bypassing all HTTP-based processing. This does make doing things like graphql-upload which involve a pre-processing step in the HTTP process challenging. I think we should keep executeOperation around as a simple hook for running operations when we don't care about HTTP stuff, but also make it easier (through better documentation or improvements) to test your full HTTP server.