Apollo Server 2.6 中的未知类型“上传”

Question

I want to upload a file through GraphQL, and followed this article .

Here's the my schema:

extend type Mutation {
  bannerAdd(
    title: String!
    image: Upload
  ): ID
}

However when I run the app, this gives me this error:

Unknown type "Upload". Did you mean "Float"?

Followed above article, Apollo Server will automatically generate Upload scalar, but why this is happening?

Also define Upload scalar manually also not working:

scalar Upload

...

Gives me this error:

Error: There can be only one type named "Upload".

Seems nothing wrong with my code. Is there an anything that I missed? Using Node@10.14.2, Apollo Server@2.6.1, Apollo Server Express@2.6.1 and polka@0.5.2.

Any advice will very appreciate it.

Answer 1

Fix this problem with GraphQLUpload of Apollo Server for create a custom scalar called FileUpload .

Server setup with Apollo Server:

const {ApolloServer, gql, GraphQLUpload} = require('apollo-server');

const typeDefs = gql`
  scalar FileUpload

  type File {
    filename: String!
    mimetype: String!
    encoding: String!
  }

  type Query {
    uploads: [File]
  }

  type Mutation {
    singleUpload(file: FileUpload!): File!
  }
`;

const resolvers = {
  FileUpload: GraphQLUpload,
  Query: {
    uploads: (parent, args) => {},
  },
  Mutation: {
    singleUpload: async (_, {file}) => {
      const {createReadStream, filename, mimetype, encoding} = await file;
      const stream = createReadStream();

      // Rest of your code: validate file, save in your DB and static storage

      return {filename, mimetype, encoding};
    },
  },
};

const server = new ApolloServer({
  typeDefs,
  resolvers,
});

server.listen().then(({url}) => {
  console.log(`🚀 Server ready at ${url}`);
});

Client Setup with Apollo Client and React.js:

You need to install the apollo-upload-client package too.

import React from 'react';
import ReactDOM from 'react-dom';
import { ApolloClient, InMemoryCache, ApolloProvider, gql, useMutation } from '@apollo/client';
import { createUploadLink } from 'apollo-upload-client';

const httpLink = createUploadLink({
  uri: 'http://localhost:4000'
});

const client = new ApolloClient({
  link: httpLink,
  cache: new InMemoryCache()
});


const UPLOAD_FILE = gql`
  mutation uploadFile($file: FileUpload!) {
    singleUpload(file: $file) {
      filename
      mimetype
      encoding
    }
  }
`;

function FileInput() {
  const [uploadFile] = useMutation(UPLOAD_FILE);

  return (
    <input
      type="file"
      required
      onChange={({target: {validity, files: [file]}}) =>
        validity.valid && uploadFile({variables: {file}})
      }
    />
  );
}

function App() {
  return (
    <ApolloProvider client={client}>
      <div>
        <FileInput/>
      </div>
    </ApolloProvider>
  );
}

ReactDOM.render(
  <React.StrictMode>
    <App/>
  </React.StrictMode>,
  document.getElementById('root')
);

Answer 2

Here's the solution what I did, adding custom scalar named "FileUpload" and add GraphQLUpload as resolver like this:

import { GraphQLUpload } from 'graphql-upload';

export const resolvers = {
  FileUpload: GraphQLUpload
};

It works great, but it could be not perfect solution. Hope apollo fix this soon.

PS To upload file from your browser, you also need to set upload link in Apollo Client properly. Here's my code:

import { ApolloLink, split } from 'apollo-link';
import { createHttpLink } from 'apollo-link-http';
import { createUploadLink } from 'apollo-upload-client';

// Create HTTP Link
const httpLink = createHttpLink({
  uri: ...,
  credentials: 'include'
});

// Create File Upload Link
const isFile = value =>
  (typeof File !== 'undefined' && value instanceof File) || (typeof Blob !== 'undefined' && value instanceof Blob);
const isUpload = ({ variables }) => Object.values(variables).some(isFile);
const uploadLink = createUploadLink({
  uri: ...
  credentials: 'include'
});

const terminatingLink = (isUpload, uploadLink, httpLink);

const link = ApolloLink.from([<Some Other Link...>, <Another Other Link...>, terminatingLink]);

const apolloClient = new ApolloClient({
  link,
  ...
});

Answer 3

This issue can be caused by passing an executable schema ( schema option) when initializing your server instead of the newer API of passing typeDefs and resolvers separately.

Old:

const server = new ApolloServer({
    schema: makeExecutableSchema({ typeDefs, resolvers })
})

New:

const server = new ApolloServer({
    typeDefs,
    resolvers,
})

Or as explained in the docs :

Note: When using typeDefs, Apollo Server adds scalar Upload to your schema, so any existing declaration of scalar Upload in the type definitions should be removed. If you create your schema with makeExecutableSchema and pass it to ApolloServer constructor using the schema param, make sure to include scalar Upload .