HybridModelBinding

For those who want the utmost flexibility in model binding.

The hybrid approach differs from traditional model binding since you get to work with both IModelBinder and IValueProvider. This means your model can first get bound with data from the body of a request, and then potentially get updated with data from route or querystring-attributes (in that order). This has the most benefit for users who prefer to have one-model for their request representations.

Examples

ASP.NET Core 2.2

dotnet add package HybridModelBinding

Startup.cs

// Boilerplate...

public void ConfigureServices(IServiceCollection services)
{
    // Add framework services.
    services
        .AddMvc()
        .AddHybridModelBinder();
}

Model

NEW WAY!

(version 0.14.0+) New implementation will allow a bit more flexibility and expandability for future features.

using HybridModelBinding;

public class IndexModel
{
    [HybridBindProperty(new[] { Source.Header, Source.Body, Source.Form, Source.QueryString, Source.Route })]
    public int? Age { get; set; }

    /// <summary>
    /// For this specific source, we want to bind to a header-key of `X-Name`.
    /// Additionally, this has higher-precedence when looking for a binding-source.
    /// </summary>
    [HybridBindProperty(Source.Header, "X-Name")]

    /// <summary>
    /// These are bound using the source-key of `Name`.
    /// </summary>
    [HybridBindProperty(new[] { Source.Body, Source.Form, Source.QueryString, Source.Route })]
    public string Name { get; set; }
}

HybridBindProperty also allows specifying order. This is implicitly set based on the line-number of the attribute. It can also be explicitly set to avoid confusion:

[HybridBindProperty(Source.Header, "X-Name", order: 5)]
[HybridBindProperty(new[] { Source.Body, Source.Form, Source.QueryString, Source.Route }, order: 10)]
public string Name { get; set; }

Declaring multiple attributes on the same line may cause unpredictable results and should be avoided (unless using explicit ordering):

[HybridBindProperty(Source.Header, "X-Name")][HybridBindProperty(new[] { Source.Body, Source.Form, Source.QueryString, Source.Route })]
public string Name { get; set; }

This way is also valid, but may look odd depending whether you read lists top-bottom or bottom-top. In this case, the Source.Body...-attribute is given higher priority.

[HybridBindProperty(Source.Header, "X-Name", order: 10)]
[HybridBindProperty(new[] { Source.Body, Source.Form, Source.QueryString, Source.Route }, order: 5)]
public string Name { get; set; }

⚠️ Obsolete way

No specific timeline for complete removal, but [From] will not be getting updates. [From] and [HybridBindProperty] can be used together on the same property. Ordering rules will apply [From] first.

using HybridModelBinding;

public class IndexModel
{
    [From(Source.Body, Source.QueryString, Source.Route)]
    public int? Age { get; set; }

    // Specific re-ordering to show `route` comes first!
    [From(Source.Body, Source.Form, Source.Route, Source.QueryString)]
    public string Name { get; set; }
}

Controller

[HttpGet]
[Route("{age?}/{name?}")]
public IActionResult Index(IndexModel model)
{ }

View

<h3>Age: @(Model.Age.HasValue ? Model.Age.ToString() : "N/A")</h3>
<h3>Name: @(string.IsNullOrEmpty(Model.Name) ? "N/A" : Model.Name)</h3>

By adding the convention-instance, any controller-action with one-parameter will automatically get associated with the hybrid binder. DefaultHybridModelBinderProvider is built-in and is setup to bind data in the following order: body => form-values => route-values => querystring-values => header-values. If you do not want to use the convention, you can also decorate your model-parameter with [From].

Results

Based on the setup above, here is how various URIs will get parsed/rendered:

/

<h3>Age: N/A</h3>
<h3>Name: N/A</h3>

/10

<h3>Age: 10</h3>
<h3>Name: N/A</h3>

/10/Bill

<h3>Age: 10</h3>
<h3>Name: Bill</h3>

/10/Bill?age=20

<h3>Age: 20</h3>
<h3>Name: Bill</h3>

/10/Bill?age=20&name=Boga

<h3>Age: 20</h3>
<h3>Name: Bill</h3> <!--note how the querystring does not get bound since the route comes first in the [From...] ordering-->

Example using headers and alternate-naming

curl -X GET \
  http://localhost/10/Bill?name=Boga \
  -H 'X-Name: Billy'

<h3>Age: 20</h3>
<h3>Name: Billy</h3>

rgonek / hybrid-model-binding