Can't get all request fields from query

[RichardLindhout]

What happened?

I'm using https://relay.dev/ as client library where you can put data inside fragments to structure your query more logically.
This is query Relay executes.

query FlowTreeQuery(
  $flowId: ID!
) {
  flowBlocks(flowId: $flowId) {
    id
    flowBlock {
      id
    }
    block {
      title
      id
    }
    blockChoice {
      id
    }
    ...FlowBlock_flowBlock
  }
}

fragment BlockAmount_blockAmount on Block {
  title
}

fragment BlockChoices_blockChoices on Block {
  blockChoices {
    id
    title
    slug
  }
}

fragment BlockInput_blockInput on Block {
  title
}

fragment BlockTypeAssigner_blockTypeAssigner on Block {
  id
}

fragment FlowBlock_flowBlock on FlowBlock {
  block {
    id
    blockType
    ...BlockChoices_blockChoices
    ...BlockAmount_blockAmount
    ...BlockInput_blockInput
    ...BlockTypeAssigner_blockTypeAssigner
  }
}

I called

fields := graphql.CollectAllFields(ctx)
	for _, f := range fields {
		fmt.Println(f)
	}

It returned:

id
flowBlock
block
blockChoice

What did you expect?

I expected at least

flowBlock
block
block.blockChoices
blockChoice

And even better something like this:

flowBlock
flowBlock.id
block
block.blockType
block.blockChoices
block.blockChoices.id
block.blockChoices.title
block.blockChoices.slug
block.id
block.title
blockChoice
blockChoice.id

Minimal graphql.schema and models to reproduce

type Block implements Node {
  id: ID!
  title: String!
  description: String
  slug: String
  blockType: String!
  blockChoices: [BlockChoice!]
}

type BlockChoice implements Node {
  id: ID!
  block: Block
  title: String!
  description: String
  slug: String
  imgUrl: String
}

type Flow implements Node {
  id: ID!
  title: String!
  description: String
  expression: String
  flowBlocks: [FlowBlock!]
}

type FlowBlock implements Node {
  id: ID!
  flowBlock: FlowBlock
  block: Block
  blockChoice: BlockChoice
  flow: Flow!
  flowBlocks: [FlowBlock]!
}

interface Node {
  id: ID!
}

type RootQueryType {
  node(id: ID!): Node
}

type Query {
  flowBlocks(flowId: ID!, ids: [ID!]): [FlowBlock!]!
}

versions

• gqlgen version
  v0.10.2-dev
• go version
  go version go1.13 darwin/amd64
• go module version
  github.com/99designs/gqlgen v0.10.2

[RichardLindhout]

Ok, I've resolved this
Say we have the following GraphQL query

Updated examples 11 May 2020: New PR for:
Also look at for most recent example: https://gqlgen.com/reference/field-collection/

query {
  flowBlocks {
    id
    block {
      id
      title
      type
      choices {
        id
        title
        description
        slug
      }
    }
  }
}

We don't want to overfetch our database so we want to know which field are requested.
Here is an example which get's all requested field as convenient string slice, which can be easily checked.

func GetPreloads(ctx context.Context) []string {
	return GetNestedPreloads(
		graphql.GetOperationContext(ctx),
		graphql.CollectFieldsCtx(ctx, nil),
		"",
	)
}

func GetNestedPreloads(ctx *graphql.OperationContext, fields []graphql.CollectedField, prefix string) (preloads []string) {
	for _, column := range fields {
		prefixColumn := GetPreloadString(prefix, column.Name)
		preloads = append(preloads, prefixColumn)
		preloads = append(preloads, GetNestedPreloads(ctx, graphql.CollectFields(ctx, column.Selections, nil), prefixColumn)...)
	}
	return
}

func GetPreloadString(prefix, name string) string {
	if len(prefix) > 0 {
		return prefix + "." + name
	}
	return name
}

So if we call these helpers in our resolver:

func (r *queryResolver) FlowBlocks(ctx context.Context) ([]*FlowBlock, error) {
	preloads := getPreloads(ctx)

it will result in the following string slice:

["id", "block", "block.id", "block.title", "block.type", "block.choices", "block.choices.id", "block.choices.title", "block.choices.description", "block.choices.slug"]

[RichardLindhout]

@vektah I think a lot of people want something like this, maybe we could describe this in the documentation?

[RichardLindhout]

Related: #746

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[RichardLindhout]

@vektah I've made a pull request for this :)