Apollo GraphQL Server-从缓存插件访问查询参数

如何解决Apollo GraphQL Server-从缓存插件访问查询参数

我有一个使用apollo-server-plugin-response-cache插件的Apollo GraphQL服务器，我需要根据传入参数确定是否要写入缓存。我已经设置了插件，并且正在使用shouldWriteToCache挂钩。我可以打印出传递到挂钩中的GraphQLRequestContext对象，并且可以看到完整的请求源，但是request.variables为空。除了解析query本身之外，如何在此挂钩中访问解析器的实际参数？ （在下面的示例中，我需要值为param2。）

Apollo服务器：

new ApolloServer({
    introspection: true,playground: true,subscriptions: false,typeDefs,resolvers,cacheControl: {
        defaultMaxAge: 60
    },plugins: [
        apolloServerPluginResponseCache({
            cache,// This is a "apollo-server-cache-redis" instance
            shouldWriteToCache: (requestContext) => {
                
                // I get a lot of info here,including the source query,but not the 
                // parsed out query variables
                console.log(requestContext.request);
                
                // What I want to do here is:
                return !context.request.variables.param2
                // but `variables` is empty,and I can't see that value parsed anywhere else
            }
        })
    ]
})

这是我的解析器：

export async function exapi(variables,context) {
  // in here I use context.param1 and context.param2
  // ...
}

我也尝试过：

export async function exapi(variables,{ param1,param2 }) {
  // ...
}

这是我从上面的代码中注销的内容：

{
  query: '{\n' +
    '  exapi(param1: "value1",param2: true) {\n' +
    '    records\n' +
    '  }\n' +
    '}\n',operationName: null,variables: {},// <-- this is empty?! How can I get param2's value??
  extensions: undefined,http: Request {
    size: 0,timeout: 0,follow: 20,compress: true,counter: 0,agent: undefined,[Symbol(Body internals)]: { body: null,disturbed: false,error: null },[Symbol(Request internals)]: {
      method: 'POST',redirect: 'follow',headers: [Headers],parsedURL: [Url],signal: null
    }
  }
}

解决方法

1. 如果不为GraphQL查询提供variables，则可以通过AST的ArgumentNode从GraphQL查询字符串中获取参数

2. 如果为GraphQL查询提供variables，则将从requestContext.request.variables获取。

例如

server.js：

import apolloServerPluginResponseCache from 'apollo-server-plugin-response-cache';
import { ApolloServer,gql } from 'apollo-server';
import { RedisCache } from 'apollo-server-cache-redis';

const typeDefs = gql`
  type Query {
    exapi(param1: String,param2: Boolean): String
  }
`;
const resolvers = {
  Query: {
    exapi: (_,{ param1,param2 }) => 'teresa teng',},};

const cache = new RedisCache({ host: 'localhost',port: 6379 });

const server = new ApolloServer({
  introspection: true,playground: true,subscriptions: false,typeDefs,resolvers,cacheControl: {
    defaultMaxAge: 60,plugins: [
    apolloServerPluginResponseCache({
      cache,shouldWriteToCache: (requestContext) => {
        console.log(requestContext.document.definitions[0].selectionSet.selections[0].arguments);
        return true;
      },}),],});
server.listen().then(({ url }) => console.log(`? Server ready at ${url}`));

GraphQL查询：

query{
  exapi(param1: "value1",param2: true) 
}

服务器日志打印param1和param2参数：

? Server ready at http://localhost:4000/
[]
[ { kind: 'Argument',name: { kind: 'Name',value: 'param1',loc: [Object] },value:
     { kind: 'StringValue',value: 'value1',block: false,loc: { start: 15,end: 31 } },{ kind: 'Argument',value: 'param2',value: { kind: 'BooleanValue',value: true,loc: { start: 33,end: 45 } } ]