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Documentation Index

Fetch the complete documentation index at: https://docs.neuro-tech.io/llms.txt

Use this file to discover all available pages before exploring further.

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Binding and Responses

Learn how the router binds route, query, and body values and turns return values into JSON

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The default binding model

For attributed controller methods, the router infers where values come from:
  • For POST, PUT, and PATCH, one class-type parameter is treated as the request body
  • Parameters whose names match route placeholders are read from the route
  • Remaining scalar parameters are read from the query string

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Implicit binding example

[Controller]
[Route("/orders")]
public sealed class OrdersController : ControllerBase
{
    [HttpPost("/[orderId]")]
    public Task<OrderResponse> Update(OrderUpdate Body, string OrderId, string? Sort)
    {
        return Task.FromResult(new OrderResponse
        {
            OrderId = OrderId,
            Sort = Sort,
            Description = Body.Description
        });
    }
}

public sealed class OrderUpdate
{
    public string Description { get; set; } = string.Empty;
}

public sealed class OrderResponse
{
    public string OrderId { get; set; } = string.Empty;
    public string? Sort { get; set; }
    public string Description { get; set; } = string.Empty;
}
  • Body — from the JSON body
  • OrderId — from /orders/[orderId]
  • Sort — from ?sort=...

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Explicit binding example

[HttpPost("/[orderId]")]
public Task<OrderResponse> Update(
    [FromBody] OrderUpdate Body,
    [FromRoute] string OrderId,
    [FromQuery] string? Sort)
{
    return Task.FromResult(new OrderResponse
    {
        OrderId = OrderId,
        Sort = Sort,
        Description = Body.Description
    });
}
Explicit attributes:
  • [FromBody]
  • [FromRoute]
  • [FromQuery]

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Important binding rules

  • Only one body parameter is allowed
  • [FromBody] is only valid on POST, PUT, and PATCH
  • [FromBody] must target a class-type parameter
  • Missing required route or query values return 400 Bad Request
  • Nullable query parameters can be omitted and bind as null

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Returning JSON

Non-raw controller methods should return Task<T>. The returned object is serialized to JSON automatically. 
[HttpGet("/[userId]")]
public Task<UserResponse> Get(string UserId)
{
    return Task.FromResult(new UserResponse
    {
        UserId = UserId,
        DisplayName = "Ada"
    });
}

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Returning errors

For attributed methods, throw an HTTP exception: 
[HttpGet("/[userId]")]
public Task<UserResponse> Get(string UserId)
{
    if (UserId == "missing")
        throw new NotFoundException(new RestApiErrorResponse("User not found.", "user_not_found"));

    if (UserId == "bad")
        throw new BadRequestException(new RestApiErrorResponse("User id is invalid.", "invalid_user_id"));

    return Task.FromResult(new UserResponse
    {
        UserId = UserId,
        DisplayName = "Ada"
    });
}
Useful helpers:
  • RestApiErrorResponse — simple { message, error_code } payload
  • ClientError — carries status code, message, localization key, and error code
  • Expected<T, E> — models success and failure explicitly before converting to HTTP
If an unexpected exception escapes the controller, the router converts it into an internal server error with code internal_server_exception. Middleware and Pipeline shows how to add cross-cutting behavior before and after your endpoints run.