Getting complete query string from inside of resolver

Question

I'm new to nodejs and apollo server, so dont judje me.

Problem sounds exactly same as title: "how to get graphql string inside resolver function?".

Actually, you have four args in every resolver: parent, args, context, info. Some info here: https://www.apollographql.com/docs/apollo-server/essentials/data#type-signature

I made my mind to write function, that gathers nested object inside context to regenerate query string. Why I need it? Good question. I'm writing microservice, so when i got nested query to field wich is outside from current microservice I pass query by http.

My resolver:

eventByID: async (root, args, context) => {
const event = await EventModel.findById(root.id);
event.creator = await nestedContextProvider(context, 'creator', event.creator);
return eventFascade(event); //just fascade for object - nothing serious

},

It refers to nestedContextProvider for solving nested context:

const nestedQueryTraverser = (nestedQueryArray) => {
const nestedQueryTraversed = nestedQueryArray.selectionSet.selections.map(element => (
element.selectionSet === undefined
  ? element.name.value
  : `${element.name.value}{${nestedQueryTraverser(element)}}`));
return nestedQueryTraversed;
};

const nestedContextProvider = async (context, checkField, ID) => {
if (context.operation.selectionSet.selections[0].selectionSet.selections
.find(selector => selector.name.value === checkField)) {
let nestedFieldsArr = context.operation.selectionSet.selections[0]
  .selectionSet.selections.find(selector => selector.name.value === checkField);
nestedFieldsArr = nestedQueryTraverser(nestedFieldsArr);
const a = (await users(ID, nestedFieldsArr));
return a.data.usersByIDs[0];
}
return ID;
};

So it works for me, but I know there must be better solution.

Any ideas?

FWIW, you may want to look into creating executable, remote schemas and then stitching them together rather than handling delegating the field resolution yourself. — Daniel Rearden

Daniel Rearden Daniel Rearden · Accepted Answer · 2019-04-26T12:15:05

The graphql package includes a print function that takes any AST and returns the string representation, so you can do something like this:

const { print } = require('graphql')

function anyResolver (parent, args, context, info) {
  const operationString = print(info.operation)
  // Fragments are not included in the operation, but we still need to print
  // them otherwise our document will reference non-existing fragments
  const fragmentsString = Object.keys(info.fragments)
    .map(fragmentName => print(info.fragments[fragmentName]))
    .join('\n\n')
  const documentString = `${operationString}\n\n${fragmentsString}`
}

Getting complete query string from inside of resolver

1 Answers