NodeJS create and POST file with GQL - node.js

Question

I've been unable to figure out in NodeJS how to:
create a "file" in memory from a raw string; and,
how to POST that data to another server that expects a multipart/form-data payload.
Seems you cannot use the Blob or File classes in NodeJS.
I've read the pattern should be to use the Buffer class.
I still cannot get it to work with Buffers.
My GQL Datasoruce class looks something like:
const { RESTDataSource } = require('apollo-datasource-rest');
const FormData = require('form-data');
export default class MyDatasource extends RESTDataSource {
async postFileToServer({ string }) {
const inMemoryFile = Buffer.from(string, 'utf-8');
const myForm = new FormData();
myForm.append('file', inMemoryFile, 'file.txt');
const url = 'http://examnple.com';
const opts = { headers: { 'Content-Type': 'multipart/form-data' } };
return await this.post(url, myForm, opts);
}
}
The endpoint I want to hit works fine when I use Postman to make the API call with a file from my local machine. However, I need the GQL server to create the file from a raw string to afterwards call the example.com endpoint that is expecting a multipart/form-data.
The above example code always gives me an error of Status 400 and SyntaxError: Unexpected token - in JSON at position 0

Answer 1

File upload works for me using the apollo-datasource-rest package. Here is an example:
server.ts:
import { ApolloServer, gql } from 'apollo-server';
import MyDatasource from './datasource';
const typeDefs = gql`
type Query {
dummy: String
}
type Mutation {
upload: String
}
`;
const resolvers = {
Mutation: {
upload(_, __, { dataSources }) {
return dataSources.uploadAPI.postFileToServer({ str: '1234' });
},
},
};
const server = new ApolloServer({
typeDefs,
resolvers,
dataSources: () => {
return {
uploadAPI: new MyDatasource(),
};
},
});
const port = 3001;
server.listen(port).then(({ url }) => console.log(`🚀 Server ready at ${url}`));
datasource.ts:
import { RESTDataSource } from 'apollo-datasource-rest';
import FormData from 'form-data';
export default class MyDatasource extends RESTDataSource {
public async postFileToServer({ str }) {
const inMemoryFile = Buffer.from(str, 'utf-8');
const myForm = new FormData();
myForm.append('file', inMemoryFile, 'file.txt');
const url = 'http://localhost:3000/upload';
return this.post(url, myForm);
}
}
uploadServer.ts:
import multer from 'multer';
import express from 'express';
import path from 'path';
const upload = multer({ dest: path.resolve(__dirname, 'uploads/') });
const app = express();
const port = 3000;
app.post('/upload', upload.single('file'), (req, res) => {
console.log(req.file);
console.log(req.body);
res.sendStatus(200);
});
app.listen(port, () => {
console.log(`upload server is listening on http://localhost:${port}`);
});
The logs printed in the controller of /upload API:
{
fieldname: 'file',
originalname: 'file.txt',
encoding: '7bit',
mimetype: 'text/plain',
destination: '/Users/ldu020/workspace/github.com/mrdulin/apollo-graphql-tutorial/src/stackoverflow/63181608/uploads',
filename: '3cba4dded6089479ad495e2fb2daac21',
path: '/Users/ldu020/workspace/github.com/mrdulin/apollo-graphql-tutorial/src/stackoverflow/63181608/uploads/3cba4dded6089479ad495e2fb2daac21',
size: 4
}
[Object: null prototype] {}
source code: https://github.com/mrdulin/apollo-graphql-tutorial/tree/master/src/stackoverflow/63181608