GraphQL query result for object that does not exist

Question

I have a GraphQL query that calls a REST service to get the return object. The query contains an Id parameter that is then passed to the service. However, the REST service can respond with http status 404 Not Found if an object with that Id does not exist. That seems like the right response.

How do you model a Not Found response in GraphQL? Is there a way to inform the GQL caller that something does not exist?

Update
Some options I am considering:

Return null
Change the GrqlhQL Query to return a list of objects and return empty list of nothing is found
Return some kind of error object with an error code

but it is unclear if there is a recommended practice in GQL API design.

Daydreaming Duck · Accepted Answer · 2020-04-12 11:17:48Z

3

You might treat it as an error and handle it accordingly.

I recommend you to check the GraphQL spec, the paragraph about error handling.
I hope it contains exactly what you are looking for.
Basically, you should return whatever you could, and inform a client about potential problems in the "errors" field.

The example from the documentation:
Request:

{
  hero(episode: $episode) {
    name
    heroFriends: friends {
      id
      name
    }
  }
}

Response:

{
  "errors": [
    {
      "message": "Name for character with ID 1002 could not be fetched.",
      "locations": [ { "line": 6, "column": 7 } ],
      "path": [ "hero", "heroFriends", 1, "name" ]
    }
  ],
  "data": {
    "hero": {
      "name": "R2-D2",
      "heroFriends": [
        {
          "id": "1000",
          "name": "Luke Skywalker"
        },
        {
          "id": "1002",
          "name": null
        },
        {
          "id": "1003",
          "name": "Leia Organa"
        }
      ]
    }
  }
}

edited Apr 12, 2020 at 11:17

answered Apr 12, 2020 at 11:09

Daydreaming Duck

2,3103 gold badges22 silver badges25 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Andrejs Over a year ago

Thank you, it makes sense! I am wondering though how a client would distinguish between different type of errors and act accordingly. - There might be a network or database error on the REST service. - Or the client might be requesting data that does not exist. In each scenario a client (say mobile app) needs to react differently.

Daydreaming Duck Over a year ago

@Andrejs the responsibility of the backend is to provide enough information for the client to distinguish these cases. If "message" and "path" it is not enough, you could use "extensions" entry and provide a code, a timestamp, a list of developers liable for this issue, the phone of your manager's grandma and whatever else you want (spec.graphql.org/draft/#sel-IAPHRLZBABABKonO)

Andrejs Over a year ago

Aha, extensions seems like the way to be explicit about the error type. Thanks for that!

Mohamed Aarab Over a year ago

but "not found" is not an error rather than a success response with no data in it, therefore i dont think is a good idea to consider it as an error.

Joakim Jäderberg Over a year ago

@MohamedAarab I'd say "Not found" is an error. You expect something to be there but it isn't. What we're trying to replicate here is 404 - Not found which falls under errors. It might help the client understand why something is missing rather than actually having the value null.

|

Collectives™ on Stack Overflow

GraphQL query result for object that does not exist

1 Answer 1

7 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

7 Comments

Your Answer

Sign up or log in

Post as a guest

Related