Should we encourage returning null when id passed to xxxById was not found?

[gojanpaolo]

In graphql-workshop, the xxxById functions (e.g. SpeakerById) defines non-nullable return types. This results to an error when the entity with the given id argument was not found.

The Relay's spec says that we should return null instead: https://relay.dev/graphql/objectidentification.htm#sec-Node-root-field

The server must make a best effort to fetch this data, but it may not always be possible; for example, the server may return a User with a valid id, but when the request is made to refetch that user with the node root field, the user’s database may be unavailable, or the user may have deleted their account. In this case, the result of querying this field should be null.

Should we encourage implementation that returns null for such cases?

[damikun]

In graphql-workshop, the xxxById functions (e.g. SpeakerById) defines non-nullable return types. This results to an error when the entity with the given id argument was not found.

The Relay's spec says that we should return null instead: https://relay.dev/graphql/objectidentification.htm#sec-Node-root-field

The server must make a best effort to fetch this data, but it may not always be possible; for example, the server may return a User with a valid id, but when the request is made to refetch that user with the node root field, the user’s database may be unavailable, or the user may have deleted their account. In this case, the result of querying this field should be null.

Should we encourage implementation that returns null for such cases?

All is about how you define query response... It is up on you...

The relay spec says if there is error return null and write this error to error[] of Graphql response.. That is basic behaviour... All is how you define types.. You can return UserNotFound object.. it is better representation like null in this case.. (working with response unions) Twitter is building something similar.. This pattern is common for mutation payload to return union but also useful for query response.. It needs more code and know something about unions and interfaces...

Don't take workshop as way how the program your app. This workshop is introduction to HC server and give you easy overview.. Some stuff are just dummy and simplified for people to understand quick and should not be used in that way if you wanna have robust GQL server.. So take principles from workshop...