yarden-zamir / ronsijm.modelrebindingfromroute

Library with a IModelBinder which will rebind route input into a model

Model Rebinding From Route

This library provides an IModelBinderProvider and an IModelBinder which makes it easy to have REST-like paths, but still conserve all input data into a singular model.

Problem Example

Consider you have an application with books, and books have pages. You want to POST text to a specific page.

Traditionally your API controller would look like this:

    [HttpPost("[controller]/book/{bookId}/page/{pageId}")]
    public string Echo(string bookId, string pageId, PageContent content)

This is fine, however if your project gets bigger and bigger, you'll probably start to add custom IActionFilters which will take input objects for processing purposes.

This is where the issue starts and the Model Rebinding comes in.

Problem solution

With this library, you are able to write API controllers like so:

    [HttpPost("[controller]/book/{bookId}/page/{pageId}")]
    public string Echo(BookRequestModel bookRequestModel)

The BookRequestModel has the following implementation:

    public class BookRequestModel
    {
        [FromRoute]
        public string BookId { get; set; }

        [FromRoute]
        public string PageId { get; set; }
    }

Note that the property names must match the path names, that's how the model rebinder will know where to rebind which route value, and the properties must have an [FromRoute] attribute. Mainly for performance reasons, so that if the model is a traditional model without any rebinding properties, the default binders are used.

Usage

Install the package:

install-package RonSijm.ModelRebindingFromRoute

Wire the model rebinder into your startup like so:

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers(options =>
        {
            options.ModelBinderProviders.Insert(0, new ModelBindingProviderInterceptor(options.ModelBinderProviders));
        });
    }

Note: It's important to wire it by using Insert(0) - this way the rebinder is used with as first attempt. Otherwise a default binder will pick this up, and if it's capable of binding, the rebinder is skipped entirely.