Question: How to read the requested fields in Resolve about graphql HOT 7 CLOSED

To answer my own question, here's how I solved this:

Assume you have the query:

query {
  companies {
    id,
    name
  }
}

And you want to know whether the companies fields contain id or name or other fields.
Use the following func

func getSelectedFields(selectionPath []string,
    resolveParams graphql.ResolveParams) []string {
    fields := resolveParams.Info.FieldASTs
    for _, propName := range selectionPath {
        found := false
        for _, field := range fields {
            if field.Name.Value == propName {
                selections := field.SelectionSet.Selections
                fields = make([]*ast.Field, 0)
                for _, selection := range selections {
                    fields = append(fields, selection.(*ast.Field))
                }
                found = true
                break
            }
        }
        if !found {
            return []string{}
        }
    }
    var collect []string
    for _, field := range fields {
        collect = append(collect, field.Name.Value)
    }
    return collect
}

And invoke it like this:

getSelectedFields([]string{"companies"}, resolveParams) 
// this will return []string{"id", "name"}

In case you have a "path" you want to select from, e.g.

query {
  a {
    b {
      x,
      y,
      z
    }
  }
}

Then you'd call it like this:

getSelectedFields([]string{"a", "b"}, resolveParams)
// Returns []string{"x", "y", "z"}

For context, this problem had also been discussed here: graphql/graphql-js#19 as well as mentioned here http://pcarion.com/2015/09/26/graphql-resolve/

from graphql.

Thanks! I'm going to use this solution. But I still think the library should provide a straightforward way to access this.

from graphql.

look at https://godoc.org/github.com/graphql-go/graphql#ResolveParams

you can access graphql query variables through Args which is map[string]interface{}, keyed with parameter name.

from graphql.

Thanks @bsr203 but unfortunately this isn't what I'm looking for.
Yes, I can access the query variables, but what I want is to access the list of requested fields (it's the first time I use graphql so I hope my terminology is right...)

So if I had a query:

query {
  companies(arg1: 5.4) {
    id,
    name
  }
}

What you're suggesting is being able to access arg1, which indeed is required.
But what I'm asking, on top of that, is being able to access the list of requested fields, e.g. I want to know that the user asked for the fields id and name but did not ask for other fields.
My motivation is that I'm sending a query to a database and in this query I request a list of fields. I want to know what fields to include in the select statement.

from graphql.

thank you for posting the solution. I too may want to use it one day, but not there yet. cheers.

from graphql.

Just an FYI for anyone reading this, I used the same solution, and it breaks if the client uses fragments:

[interface conversion: ast.Selection is *ast.FragmentSpread, not *ast.Field]

I'll post here when I find a solution to this.

from graphql.

I've posted my modified solution here, which works for queries that include fragments: #157 (comment)

from graphql.