LenzEng.Utilities.Cqrs.GraphQL 0.4.0

LenzEng.Utilities.Cqrs.GraphQL

GraphQL integration for LenzEng.Utilities.Cqrs — the GraphQL sibling of LenzEng.Utilities.Cqrs.Rest. Converts the raw results your command/query handlers return into the values a GraphQL resolver returns: a typed result for queries, a CommandPayload<TResult> for mutations. Depends on no GraphQL server library — use it with HotChocolate, GraphQL.NET, or anything else.

What It Provides

Key Behaviour

• "Not found" happens automatically when a handler returns LenzEng.Utilities.Cqrs.NotFoundMarker — queries resolve to null; mutations get a NOT_FOUND-coded entry in CommandPayload.Errors.
• Validation errors land in CommandPayload<TResult>.Errors when LenzEng.Utilities.Cqrs.FluentValidation's ValidateCommandException is thrown — this package doesn't reference that one, it just catches the exception type by name from the core package.
• Conversion functions are typed as Func<object, object> rather than Func<TDomain, TDto> on purpose, so the generic handlers stay decoupled from your domain/DTO types.

Quick Start

builder.Services.AddCqrs(typeof(CreateOrderCommandHandler).Assembly);
builder.Services.AddCqrsGraphQL();

builder.Services.AddGraphQLMutation<CreateOrderCommand, Order>(opts =>
    opts.ConversionFunction = ServiceModelConverter.ConvertOrder);
builder.Services.AddGraphQLQuery<GetOrderByIdQuery, Order>();

public class Mutation
{
    private readonly IGraphQLCommandProcessor _commands;
    public Mutation(IGraphQLCommandProcessor commands) => _commands = commands;

    public Task<CommandPayload<Order>> CreateOrder(CreateOrderCommand command, CancellationToken ct)
        => _commands.ProcessAsync<CreateOrderCommand, Order>(command, ct);
}

public class Query
{
    private readonly IGraphQLQueryProcessor _queries;
    public Query(IGraphQLQueryProcessor queries) => _queries = queries;

    public Task<Order?> GetOrderById(Guid id, CancellationToken ct)
        => _queries.ProcessAsync<GetOrderByIdQuery, Order>(new GetOrderByIdQuery { OrderId = id }, ct);
}

Technical Documentation

Full reference, worked examples, and a detailed explanation of every place this package's design deviates from Cqrs.Rest (and why): src/LenzEng.Utilities.Cqrs.GraphQL — GitLab

See the Packages Work Together

The sample project's README wires this package into the same movie-catalog sample Cqrs.Rest already uses — same handlers, two transports, running side by side in one process.