Apollo GraphQL Server - Access query params from cache plugin - node.js

Question

I have an Apollo GraphQL server using the apollo-server-plugin-response-cache plugin and I need to determine whether or not I'm going to write to the cache based on incoming parameters. I have the plugin set up and I'm using the shouldWriteToCache hook. I can print out the GraphQLRequestContext object that gets passed into the hook, and I can see the full request source, but request.variables is empty. Other than parsing the query itself, how can I access the actual params for the resolver in this hook? (In the example below, I need the value of param2.)
Apollo Server:
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
}
})
]
})
Here is my resolver:
export async function exapi(variables, context) {
// in here I use context.param1 and context.param2
// ...
}
I have also tried:
export async function exapi(variables, { param1, param2 }) {
// ...
}
Here is what I get logged out from the code above:
{
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
}
}
}

Answer 1

If you didn't provide variables for GraphQL query, you could get the arguments from the GraphQL query string via ArgumentNode of AST
If you provide variables for GraphQL query, you will get them from requestContext.request.variables.
E.g.
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 query:
query{
exapi(param1: "value1", param2: true)
}
Server logs print param1 and param2 arguments:
🚀 Server ready at http://localhost:4000/
[]
[ { kind: 'Argument',
name: { kind: 'Name', value: 'param1', loc: [Object] },
value:
{ kind: 'StringValue',
value: 'value1',
block: false,
loc: [Object] },
loc: { start: 15, end: 31 } },
{ kind: 'Argument',
name: { kind: 'Name', value: 'param2', loc: [Object] },
value: { kind: 'BooleanValue', value: true, loc: [Object] },
loc: { start: 33, end: 45 } } ]