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Last update: August 26, 2024

Extend cart query with custom parameter

To extend cart queries and incorporate a custom parameter, such as a contract ID:

  1. Override the existing cart query type with the extended version and specify a custom query handler:

    services.OverrideQueryType<GetCartQuery, GetCartQueryExtended>().WithQueryHandler<CustomGetCartQueryHandler>();
    
  2. Override the ShoppingCartSearchCriteria type to include the extended version:

    AbstractTypeFactory<ShoppingCartSearchCriteria>.OverrideType<ShoppingCartSearchCriteria, ShoppingCartSearchCriteriaExtended>();
    
  3. Create an extended version of the GetCartQuery, introducing the ContractId parameter:

    public class GetCartQueryExtended : GetCartQuery
    {
        public string ContractId { get; set; }
    
        public override IEnumerable<QueryArgument> GetArguments()
        {
            foreach (var argument in base.GetArguments())
            {
                yield return argument;
            }
    
            yield return Argument<StringGraphType>(nameof(ContractId));
        }
    
        public override void Map(IResolveFieldContext context)
        {
            base.Map(context);
    
            ContractId = context.GetArgument<string>(nameof(ContractId));
        }
    }
    
  4. Implement a custom query handler to handle the extended GetCartQuery:

    public class CustomGetCartQueryHandler : GetCartQueryHandler
    {
        public CustomGetCartQueryHandler(ICartAggregateRepository cartAggregateRepository,
            ICartResponseGroupParser cartResponseGroupParser)
            : base(cartAggregateRepository, cartResponseGroupParser)
        {
        }
    
        // Override the method to include the custom ContractId parameter in the search criteria.
        protected override ShoppingCartSearchCriteria GetCartSearchCriteria(GetCartQuery request)
        {
            var requestExtended = (GetCartQueryExtended)request;
            var criteriaExtended = (ShoppingCartSearchCriteriaExtended)base.GetCartSearchCriteria(request);
    
            criteriaExtended.ContractId = requestExtended.ContractId;
    
            return criteriaExtended;
        }
    }
    

This implementation extends the original GetCartQuery by introducing a GetCartQueryExtended class that includes the additional ContractId parameter. The custom query handler, CustomGetCartQueryHandler, is responsible for handling this extended query and updating the search criteria accordingly.