如何通过Websocket协议在GraphQL中处理文件上传？

const ws = new WebSocket('ws://example.com/graphql');

ws.onopen = () => {
  const fileInput = document.querySelector('input[type="file"]');
  fileInput.addEventListener('change', (event) => {
    const file = event.target.files[0];
    const reader = new FileReader();
    reader.onload = (e) => {
      const base64Data = e.target.result.split(',')[1]; // Remove MIME type
      ws.send(JSON.stringify({
        type: 'start',
        id: '1',
        payload: {
          query: `
            mutation ($file: Upload!) {
              uploadFile(file: $file) {
                success
                message
              }
            }
          `,
          variables: { file: base64Data }
        }
      }));
    };
    reader.readAsDataURL(file);
  });
};

ws.onmessage = (event) => {
  const data = JSON.parse(event.data);
  console.log(data);
};

const { ApolloServer, gql } = require('apollo-server');
const { GraphQLUpload } = require('graphql-upload');
const { createWriteStream } = require('fs');
const { join } = require('path');

const typeDefs = gql`
  scalar Upload

  type Mutation {
    uploadFile(file: Upload!): UploadResponse!
  }

  type UploadResponse {
    success: Boolean!
    message: String!
  }
`;

const resolvers = {
  Upload: GraphQLUpload,
  Mutation: {
    uploadFile: async (_, { file }) => {
      const { createReadStream, filename } = await file;
      const stream = createReadStream();
      const path = join(__dirname, 'uploads', filename);
      await new Promise((resolve, reject) =>
        stream.pipe(createWriteStream(path)).on('finish', resolve).on('error', reject)
      );
      return { success: true, message: 'File uploaded successfully' };
    }
  }
};

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

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