README.md

postgraphile-upload-example

This app demonstrates how to add file upload support to PostGraphile using the GraphQL Multipart Request Spec.

Server:

• PostGraphile
• postgraphile-plugin-upload-field
• graphql-upload

Client:

• create-react-app
• apollo-client
• apollo-upload-client

Quick Start

Clone this repo.

In one terminal:

cd server
createdb upload_example
psql -d upload_example -f schema.sql
yarn
yarn start

In another terminal:

cd client
yarn
yarn start

The app should now be fully functional at localhost:3000. Uploaded files will be stored locally in /server/uploads.

How does it work?

The server code should be relatively straightforward if you're familiar with PostGraphile. The graphql-upload middleware handles the multipart requests using busboy. The postgraphile-plugin-upload-field plugin for PostGraphile is minimally documented, but briefly, match is a function used to specify the file upload metadata columns and resolve is a function that handles the actual file upload stream.

The client is full of React/Apollo boilerplate. The unique parts are:

• These lines in clients/src/index.js where createUploadLink replaces the usual createHttpLink in the ApolloClient constructor; and
• All of client/src/CreatePost.js, which is the actual upload form. It uses the Query and Mutation components that were added in React Apollo 2.1.

Preserving metadata

By default, the example app only stores the local file path to Postgres. To preserve additional metadata, change the header_image_file column type to JSONB and replace the resolveUpload function with the following:

async function resolveUpload(upload) {
  const { filename, mimetype, encoding, createReadStream } = upload;
  const stream = createReadStream();
  // Save file to the local filesystem
  const { id, path } = await saveLocal({ stream, filename });
  // Return metadata to save it to Postgres
  return {
    id,
    path,
    filename,
    mimetype,
    encoding
  };
}

After making this change, you'll also need to update the client app to use the path property of the object.

For a more robust solution, consider using something like postgraphile-plugin-derived-field to expose URLs through GraphQL instead of exposing the raw path/metadata.

If you're streaming file uploads to an object storage service such as S3, you can also use the derived field plugin to generate pre-signed URLs for clients.