要解决Apollo-GraphQL客户端拒绝Base64字符串数据的问题，您可以尝试使用以下解决方法：

1. 使用apollo-link-rest插件：

   import { RestLink } from 'apollo-link-rest';
   import { ApolloClient } from 'apollo-client';
   import { InMemoryCache } from 'apollo-cache-inmemory';
   
   const restLink = new RestLink({
     uri: 'https://api.example.com',
     customFetch: async (uri, options) => {
       if (options.body && options.body.variables && options.body.variables.file) {
         options.body.variables.file = options.body.variables.file.toString('base64');
       }
       return fetch(uri, options);
     },
   });
   
   const client = new ApolloClient({
     link: restLink,
     cache: new InMemoryCache(),
   });
   

2. 自定义Apollo-GraphQL链接：

   import { ApolloLink } from 'apollo-link';
   import { ApolloClient } from 'apollo-client';
   import { InMemoryCache } from 'apollo-cache-inmemory';
   import { HttpLink } from 'apollo-link-http';
   
   const customLink = new ApolloLink((operation, forward) => {
     if (operation.variables && operation.variables.file) {
       operation.variables.file = operation.variables.file.toString('base64');
     }
     return forward(operation);
   }).concat(new HttpLink({ uri: 'https://api.example.com' }));
   
   const client = new ApolloClient({
     link: customLink,
     cache: new InMemoryCache(),
   });
   

请注意，以上解决方法仅为示例，您可能需要根据您的具体情况进行调整。另外，请确保您的Base64字符串数据正确传递给Apollo-GraphQL客户端。