graphql upload typescript (graphql-upload-ts)

Minimalistic and developer friendly middleware and an Upload scalar to add support for GraphQL multipart requests (file uploads via queries and mutations) to various Node.js GraphQL servers.

Acknowledgements

This module was forked from the amazing graphql-upload-minimal. The original module is exceptionally well documented and well written. It was very easy to fork and amend.

I needed to support typescript to use it properly in typescript projects.

This project is written in typescript

• TypeScript support.
• And using a bit less memory.
• And a bit faster.
• More Examples and documentation

Does not follow strict specification

You can't have same file referenced twice in a GraphQL query/mutation.

Support

The following environments are known to be compatible:

• Node.js versions 12, 14, 16, and 18. It works in Node 10 even though the unit tests fail.
• Koa
• Express.js

See also GraphQL multipart request spec server implementations.

Setup

To install graphql-upload-ts and the graphql peer dependency from npm run:

npm install graphql-upload-ts graphql
# or
yarn add graphql-upload-ts graphql

Use the graphqlUploadKoa or graphqlUploadExpress middleware just before GraphQL middleware. Alternatively, use processRequest to create a custom middleware.

A schema built with separate SDL and resolvers (e.g. using makeExecutableSchema) requires the Upload scalar to be setup.

Usage

Clients implementing the GraphQL multipart request spec upload files as Upload scalar query or mutation variables. Their resolver values are promises that resolve file upload details for processing and storage. Files are typically streamed into cloud storage but may also be stored in the filesystem.

Express.js

Minimalistic code example showing how to upload a file along with arbitrary GraphQL data and save it to an S3 bucket.

Express.js middleware. You must put it before the main GraphQL sever middleware. Also, make sure there is no other Express.js middleware which parses multipart/form-data HTTP requests before the graphqlUploadExpress middleware!

const express = require('express');
const expressGraphql = require('express-graphql');
const { graphqlUploadExpress } = require('graphql-upload-ts');

express()
  .use(
    '/graphql',
    graphqlUploadExpress({ 
      maxFileSize: 10000000,
      maxFiles: 10,
      // If you are using framework around express like [ NestJS or Apollo Serve ]
      // use this options overrideSendResponse to allow nestjs to handle response errors like throwing exceptions
      overrideSendResponse: false 
    }),
    expressGraphql({ schema: require('./my-schema') })
  )
  .listen(3000);

GraphQL schema:

scalar Upload
input DocumentUploadInput {
  docType: String!
  file: Upload!
}

type SuccessResult {
  success: Boolean!
  message: String
}
type Mutations {
  uploadDocuments(docs: [DocumentUploadInput!]!): SuccessResult
}

GraphQL resolvers:

const { S3 } = require('aws-sdk');

const resolvers = {
  Upload: require('graphql-upload-ts').GraphQLUpload,

  Mutations: {
    async uploadDocuments(root, { docs }, ctx) {
      try {
        const s3 = new S3({ apiVersion: '2006-03-01', params: { Bucket: 'my-bucket' } });

        for (const doc of docs) {
          const { createReadStream, filename /*, fieldName, mimetype, encoding */ } = await doc.file;
          const Key = `${ctx.user.id}/${doc.docType}-${filename}`;
          await s3.upload({ Key, Body: createReadStream() }).promise();
        }

        return { success: true };
      } catch (error) {
        console.log('File upload failed', error);
        return { success: false, message: error.message };
      }
    },
  },
};

Koa

See the example Koa server and client.

Uploading multiple files

When uploading multiple files you can make use of the fieldName property to keep track of an identifier of the uploaded files. The fieldName is equal to the passed name property of the file in the multipart/form-data request. This can be modified to contain an identifier (like a UUID), for example using the formDataAppendFile in the commonly used apollo-upload-link library.

GraphQL schema:

scalar Upload
input DocumentUploadInput {
  docType: String!
  files: [Upload!]
}

type SuccessResult {
  success: Boolean!
  message: String
}
type Mutations {
  uploadDocuments(docs: [DocumentUploadInput!]!): SuccessResult
}

GraphQL resolvers:

const { S3 } = require('aws-sdk');

const resolvers = {
  Upload: require('graphql-upload-ts').GraphQLUpload,

  Mutations: {
    async uploadDocuments(root, { docs }, ctx) {
      try {
        const s3 = new S3({ apiVersion: '2006-03-01', params: { Bucket: 'my-bucket' } });

        for (const doc of docs) {
          // fieldName contains the "name" property from the multipart/form-data request.
          // Use it to pass an identifier in order to store the file in a consistent manner.
          const { createReadStream, filename, fieldName /*, mimetype, encoding */ } = await doc.file;
          const Key = `${ctx.user.id}/${doc.docType}-${fieldName}`;
          await s3.upload({ Key, Body: createReadStream() }).promise();
        }

        return { success: true };
      } catch (error) {
        console.log('File upload failed', error);
        return { success: false, message: error.message };
      }
    },
  },
};

Tips

• If you are using framework around express like [ NestJS or Apollo Serve ] use the option overrideSendResponse eg: graphqlUploadExpress({ overrideSendResponse: false }) to allow nestjs to handle response errors like throwing exceptions.

Architecture

The GraphQL multipart request spec allows a file to be used for multiple query or mutation variables (file deduplication), and for variables to be used in multiple places. GraphQL's resolvers need to be able to manage independent file streams.

busboy parses multipart request streams. Once the operations and map fields have been parsed, Upload scalar values in the GraphQL operations are populated with promises, and the operations are passed down the middleware chain to GraphQL resolvers.