Minimal Actions - array support in method signatures from querystring binding

[jchannon]

Describe the bug

When using the ASPP.NET 6 minimal hosting, querystring binding does not work with arrays/lists

To Reproduce

app.MapGet("/qs/{id:int}", HttpHandlers.GetByQueryString);

public static string GetByQueryString(int id, string name, int[] values)
{
    return id + " " + name + string.Join(",", values);
}

Adding [FromQuery(Name = "values")] to the method signature does not help either.

Exceptions (if any)

An exception is thrown when sending in a request:

curl http://localhost:5000/qs/123\?name\=dave\&values\=1\&values\=2

Unhandled exception. System.InvalidOperationException: No public static bool Int32[].TryParse(string, out Int32[]) method found for values.

Further technical details

• ASP.NET Core version 6

.NET SDK (reflecting any global.json):
 Version:   6.0.100-preview.5.21252.2
 Commit:    921395c33e

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  11.3
 OS Platform: Darwin
 RID:         osx.11.0-x64
 Base Path:   /Users/jonathan/.dotnet/sdk/6.0.100-preview.5.21252.2/

Host (useful for support):
  Version: 6.0.0-preview.5.21251.4
  Commit:  d2fba8fdc4

.NET SDKs installed:
  2.1.809 [/Users/jonathan/.dotnet/sdk]
  3.1.401 [/Users/jonathan/.dotnet/sdk]
  3.1.403 [/Users/jonathan/.dotnet/sdk]
  5.0.103 [/Users/jonathan/.dotnet/sdk]
  6.0.100-preview.5.21229.26 [/Users/jonathan/.dotnet/sdk]
  6.0.100-preview.5.21252.2 [/Users/jonathan/.dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.21 [/Users/jonathan/.dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.21 [/Users/jonathan/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.7 [/Users/jonathan/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.9 [/Users/jonathan/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.3 [/Users/jonathan/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0-preview.5.21229.9 [/Users/jonathan/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0-preview.5.21230.5 [/Users/jonathan/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.21 [/Users/jonathan/.dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.7 [/Users/jonathan/.dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.9 [/Users/jonathan/.dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.3 [/Users/jonathan/.dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-preview.5.21229.1 [/Users/jonathan/.dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-preview.5.21251.4 [/Users/jonathan/.dotnet/shared/Microsoft.NETCore.App]

To install additional .NET runtimes or SDKs:
  https://aka.ms/dotnet-download

[davidfowl]

Would this only be for simple types? Today we don't support any complex types for model binding and it conflicts with this idea

[jchannon]

Yup simple types only imo, it's a query string, you shouldn't be doing crazy stuff like json binding. I mean there's nothing stopping someone adding json in a querystring I just don't think the framework should support that

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[halter73]

What collection types should we support?

What should we do if we know the param comes from the route? Fail at startup? Provide a single-element array?

[DamianEdwards]

With the newly added support for BindAsync(HttpContext) on the target parameter type it would be easy to support this in the app or a library via a custom type, e.g. MultiValueQuery values, where MultiValueQuery has a BindAsync method on it.