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Could not bind an array of query param values with Request.Query.As<int[]>("Id")

See original GitHub issue
public sealed class AppCarterModule : CarterModule
    private static readonly Actor[] Actors = new[]
        new Actor() { Id = 1, Name = "First"},
        new Actor() { Id = 2, Name = "Second"},
        new Actor() { Id = 3, Name = "Third"},
    public AppCarterModule()
        Get("/actors", async ctx =>
            IEnumerable<Actor> result = Actors;
            // ids is always null for "/actors?Id=1&Id=3"
            var ids = ctx.Request.Query.As<int[]>("Id");
            if (ids != null)
                result = result.Where(x => ids.Contains(x.Id));
            await ctx.Response.Negotiate(result);

GET /actors?id=1&id=3 returns all 3 records instead of 2 because ctx.Request.Query.As<int[]>("Id") returns null instead of [1,3]

Repository with a failing test

public async Task Test1()
            var client = _factory.CreateClient();
            var result = await client.GetAsync("/actors?Id=1&Id=3");
            var str = await result.Content.ReadAsStringAsync();
            var array = JsonConvert.DeserializeObject<dynamic[]>(str);

            Assert.Equal(2, array.Length);

Issue Analytics

  • State:closed
  • Created 3 years ago
  • Comments:5 (3 by maintainers)

github_iconTop GitHub Comments

Deilancommented, Apr 27, 2021

I cannot provide any reference to a language- or platform-agnostic spec on that topic. But since:

  • Carter is built upon ASP.NET Core infrastructure, and aforementioned way of working with query strings is the default in ASP.NET (Core)
  • main target audience of Carter is ASP.NET (Core) developers (in past or present)

I’d say it should be also the default way in Carter too. Other ways are also would be nice to have, but as an opt-in.

(Some of) ASP.NET Core utils’, used to work with query params:

In particular:

jchannoncommented, Nov 12, 2021

To get an array you can do var ids = ctx.Request.Query.AsMultiple<int>("id");

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