Creating GraphQl Request for a list of inputs - graphql

Question

I've a query which I want to run over a list of different input. How can I do this in a single query request ?
My query looks like :
QuerySingle
query($personId:ID!, $vehicleId: ID!) {
person(personID: $personId) {
name,
gender,
hairColor
},
vehicle(id: $vehicleId) {
name,
model,
vehicleClass,
}
}
and arguments are like
{ "personId": 1, "vehicleId": "dmVoaWNsZXM6NA==" }
This runs well for a single input. Single Input Example
But I want to run it over a list of inputs I've like following :
[
{ "personId": 1, "vehicleId": "dmVoaWNsZXM6NA==" },
{ "personId": 2, "vehicleId": "dmVoaWNsZXM6Ng==" },
{ "personId": 3, "vehicleId": "dmVoaWNsZXM6Nw==" },
{ "personId": 4, "vehicleId": "dmVoaWNsZXM6OA==" },
{ "personId": 5, "vehicleId": "dmVoaWNsZXM6MTQ=" },
{ "personId": 6, "vehicleId": "dmVoaWNsZXM6MTY=" },
{ "personId": 7, "vehicleId": "dmVoaWNsZXM6MTg=" },
{ "personId": 8, "vehicleId": "dmVoaWNsZXM6MTk=" },
{ "personId": 9, "vehicleId": "dmVoaWNsZXM6MjA=" },
{ "personId": 10, "vehicleId": "dmVoaWNsZXM6MjQ=" }
]
How can I do this ?
One way which could be use aliases on person and vehicle and provide different input as different variable names. Example Query with different var aliases
QueryMultiUsingAlias
query($personId_1:ID!, $vehicleId_1: ID!,$personId_2:ID!, $vehicleId_2: ID!) {
person1: person(personID: $personId_1) {
...personData
},
vehicle1: vehicle(id: $vehicleId_1) {
...vehicleData
}
person2: person(personID: $personId_2) {
...personData
},
vehicle2: vehicle(id: $vehicleId_2) {
...vehicleData
}
}
fragment vehicleData on Vehicle {
name,
model,
vehicleClass
}
fragment personData on Person {
name,
gender,
hairColor
}
Parameters:
{
"personId_1": 1,
"vehicleId_1": "dmVoaWNsZXM6NA==",
"personId_2": 2,
"vehicleId_2": "dmVoaWNsZXM6Ng=="
}
Question I've are :
This query becomes too gross and hard to extend as more different type of data is added per input. or as more number of input parameters are added. Is there a cleaner way to represent this query ?
If there's no other way, Is there a functionality available in graphql-java to generate QueryMultiUsingAlias from QuerySingle based on input length ?

Answer 1

First, I'd first consider making the Vehicle type a field on Person (it seems like there is a relationship between and a vehicle maps to a person). You can then define your schema as follows:
type Vehicle {
// fields defining Vehicle type
}
type Person {
vehicle: Vehicle
//other fields defining Person type
}
Query {
person(personId: Int, vehicleId: Int): Person
}
Your resolvers could follow a similar implementation:
Query {
async person(obj, args, context, info) {
return await context.db.loadPersonByID(args.personId)
}
},
Person {
async vehicle(obj, args, context, info) {
return await context.db.loadVehicleByID(args.vehicleId)
}
}
Alternatively, if the result from your person db query includes the vehicleId as a property, the vehicleId should be accessible from the “obj” argument when resolving vehicle, negating the need for the vehicleId argument in the query (this is unclear though).
Finally, rather than passing an array of arguments and modifying your graph input schema in this respect, it may be cleanest to fire off a number of discrete async queries from the client using your array of arguments and wait for alll of those discrete requests to be resolved with Promise.all([query1, query2, etc.]) or equivalent. Each query would pass a personId and vehicleId from your array (assuming vehicleId is even still necessary given guidance above). You can map over your array in the following way in js as follows:
const queryResults = await Promise.all(argumentArray.map(async ({personId, vehicleId }) {
return await // fire query using personId and vehicleId
}))
}