GraphQL.HasSelectionField

I made a super cool extension method that returns whether the selection is included in a GraphQL query.


---
## Extension Method

    using System;
    using System.Linq;
    using GraphQL.Language.AST;
    using GraphQL.Types;    
    
    public static class ContextExtensions
    {
        /// <summary>
        /// Returns true if the given fieldSelector exists in the selection of the query.
        /// </summary>
        /// <param name="context">The working context</param>
        /// <param name="fieldSelector">The query of the field selector. For example items:organizationUnits:displayName</param>
        /// <param name="namespaceSeperator">The seperator character of the fieldSelector. Default is :</param>
        /// <returns></returns>
        public static bool HasSelectionField(this ResolveFieldContext<object> context, string fieldSelector, char namespaceSeperator = ':')
        {
            if (string.IsNullOrWhiteSpace(fieldSelector))
            {
                return false;
            }
    
            if (context.SubFields == null)
            {
                return false;
            }
    
            var fragments = fieldSelector.Split(new[] { namespaceSeperator }, StringSplitOptions.RemoveEmptyEntries);
    
            if (fragments.Length == 1)
            {
                return context.SubFields.ContainsKey(fragments[0]);
            }
    
            if (context.SubFields[fragments[0]] == null)
            {
                return false;
            }
    
            if (context.SubFields[fragments[0]].SelectionSet == null)
            {
                return false;
            }
    
            if (context.SubFields[fragments[0]].SelectionSet.Selections == null)
            {
                return false;
            }
    
    
            var selections = context.SubFields[fragments[0]].SelectionSet.Selections;
    
            for (var i = 1; i < fragments.Length; i++)
            {
                if (selections == null)
                {
                    return false;
                }
    
                var field = selections.Select(selection => (Field)selection).FirstOrDefault(f => f.Name == fragments[i]);
                if (field == null)
                {
                    return false;
                }
    
                if (i == fragments.Length - 1)
                {
                    return true;
                }
    
                selections = field.SelectionSet?.Selections;
            }
    
            return true;
        }
    }

---

## Usage


    protected override async Task<PagedResultDto<UserDto>> Resolve(ResolveFieldContext<object> context)
    {
        var total_count_exists = context.HasSelectionField("totalCount"); //true
        var items_name_exists = context.HasSelectionField("items:name"); //true
        var items_roles_name_exists = context.HasSelectionField("items:roles:name"); //true
        var items_organizationUnits_displayName_exists = context.HasSelectionField("items:organizationUnits:displayName"); //true
        var items_organizationUnits_xyz_exists = context.HasSelectionField("items:organizationUnits:xyz"); //false
    }


---
## Sample Query


    query MyQuery {
      users(id: 1) {
        totalCount
        items {
          name
          surname
    
          roles {
            id
            name
            displayName
          }
    
          organizationUnits {
            id
            code
            displayName
          }
        }
      }
    }