ShortGuid Model Binding (MVC or WebApi) example

MvcConfiguration.cs

// Configure binding provider for MVC during the general setup, e.g.
// ... AreaRegistration.RegisterAllAreas();
ModelBinderProviders.BinderProviders.Add(new MyProject.ModelBinders.Mvc.ShortGuidModelBinderProvider());
// ... FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);

MvcSampleController.cs

public class MvcSampleController : System.Web.Mvc.Controller
{
	/// <summary>
	/// GET /watch/00amyWGct0y_ze4lIsj2Mw?token=Xy0MVKupFES9NpmZ9TiHcw
	///
	/// ```
	/// [Details]
	/// VideoId: `00amyWGct0y_ze4lIsj2Mw` => `c9a646d3-9c61-4cb7-bfcd-ee2522c8f633`
	/// Token  : `Xy0MVKupFES9NpmZ9TiHcw` => `540c2d5f-a9ab-4414-bd36-9999f5388773
	/// ```
	/// </summary>
	/// <param name="videoId"></param>
	/// <param name="token"></param>
	/// <returns></returns>
	[Route("watch/{videoId}")]
	public ActionResult WatchVideo(
		// url path param
		ShortGuid? videoId = null,

		// query string
		ShortGuid? token = null
	)
	{
		string result = $@"[Details]
VideoId: `{videoId}` => `{videoId?.Guid.ToString() ?? "Invalid"}`
Token  : `{token}` => `{token?.Guid.ToString() ?? "None"}
";

		return Content(result, "text/plain");
	}

	public class SampleArgsModel
	{
		public ShortGuid? ChannelId { get; set; }
	}

	/// <summary>
	/// GET /watch?channelId=00amyWGct0y_ze4lIsj2Mw
	///
	/// ```
	/// ChannelId: `00amyWGct0y_ze4lIsj2Mw` => `c9a646d3-9c61-4cb7-bfcd-ee2522c8f633`
	/// ```
	/// </summary>
	/// <param name="args"></param>
	/// <returns></returns>
	[Route("watch")]
	public ActionResult WatchChannel(
		SampleArgsModel args
	)
	{
		return Content($"ChannelId: `{args.ChannelId}` => `{args.ChannelId?.Guid.ToString() ?? "Invalid"}`", "text/plain");
	}
}

MvcShortGuidModelBinder.cs

using CSharpVitamins;
using System;
using System.Web.Mvc;

namespace MyProject.ModelBinders.Mvc
{
	/// <summary>
	/// An MVC model binder to convert 22 charactater URL-safe Base64 into <see cref="ShortGuid"/> instances.
	/// </summary>
	public sealed class ShortGuidModelBinder : IModelBinder
	{
		/// <summary>
		/// Binds the model to a value by using the specified controller context and binding context.
		/// </summary>
		/// <param name="controllerContext"></param>
		/// <param name="bindingContext"></param>
		/// <returns></returns>
		public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
		{
			var result = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);

			if (null == result?.AttemptedValue)
				return null;

			// Two options exist for parsing the incoming value

			// 1. TryParse which will attempt a) 22 char ShortGuid format, then normal Guid parsing, and outputs a
			//    ShortGuid in this case. This will accept both formats e.g."00amyWGct0y_ze4lIsj2Mw" as well as
			//    "c9a646d3-9c61-4cb7-bfcd-ee2522c8f633".
			/*
			if (ShortGuid.TryParse(result.AttemptedValue, out ShortGuid parsed))
				return parsed;
			*/

			// 2. TryDecode which will only decocde the 22 char ShortGuid format, but outputs a Guid. This will
			//    only accept "00amyWGct0y_ze4lIsj2Mw".
			if (ShortGuid.TryDecode(result.AttemptedValue, out Guid decoded))
				return new ShortGuid(decoded);

			return null;
		}
	}

	/// <summary>
	/// Provider for MVC Model Binding.
	/// </summary>
	/// <example>
	/// 	<code>
	/// 		// MVC general configuration.
	/// 		ModelBinderProviders.BinderProviders.Add(new ShortGuidModelBinderProvider());
	/// 	</code>
	/// </example>
	public sealed class ShortGuidModelBinderProvider : IModelBinderProvider
	{
		ShortGuidModelBinder binder = new ShortGuidModelBinder();

		/// <summary>
		/// Returns the model binder for the specified type.
		/// <para>Supports <see cref="ShortGuid"/> and nullable `ShortGuid?`.</para>
		/// </summary>
		/// <param name="modelType"></param>
		/// <returns></returns>
		public IModelBinder GetBinder(Type modelType)
		{
			if (modelType == typeof(ShortGuid) || modelType == typeof(ShortGuid?))
				return binder;

			// Could possibly extend to also run normal Guids through here too, though YMMV.

			return null;
		}
	}
}

WebApiSampleController.cs

[RoutePrefix("api")]
public class WebApiSampleController : System.Web.Http.ApiController
{
	/// <summary>
	/// GET /api/watch/FEx1sZbSD0ugmgMAF_RGHw
	/// ```
	/// {
	///   previewId: "FEx1sZbSD0ugmgMAF_RGHw",
	///   guid: "b1754c14-d296-4b0f-a09a-030017f4461f"
	/// }
	/// ```
	/// /// </summary>
	/// <param name="previewId"></param>
	/// <returns></returns>
	[HttpGet]
	[Route("watch/{previewId}")]
	public HttpResponseMessage Watch(
		[ModelBinder(typeof(ShortGuidModelBinder))] ShortGuid previewId
	)
	{
		return Request.CreateResponse(HttpStatusCode.OK, new
		{
			PreviewId = previewId.Value,
			Guid = previewId.Guid,
		});
	}
}

WebApiShortGuidModelBinder.cs

using CSharpVitamins;
using System;
using System.Web.Http.Controllers;
using System.Web.Http.ModelBinding;

namespace MyProject.ModelBinders.WebApi
{
	/// <summary>
	/// A WebApi model binder to convert 22 charactater URL-safe Base64 into <see cref="ShortGuid"/> instances.
	/// </summary>
	public sealed class ShortGuidModelBinder : IModelBinder
	{
		/// <summary>
		/// Binds the model to a value by using the specified controller context and binding context.
		/// </summary>
		/// <param name="actionContext"></param>
		/// <param name="bindingContext"></param>
		/// <returns></returns>
		public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
		{
			var result = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);

			if (null == result)
				return false;

			// You can decide if you want this try/catch/throw here.
			try
			{
				// Two options exist for parsing the incoming value

				// 1. TryParse which will attempt a) 22 char ShortGuid format, then normal Guid parsing, and outputs a
				//    ShortGuid in this case. This will accept both formats e.g."00amyWGct0y_ze4lIsj2Mw" as well as
				//    "c9a646d3-9c61-4cb7-bfcd-ee2522c8f633".
				/*
				if (ShortGuid.TryParse(result.AttemptedValue, out ShortGuid parsed))
				{
					bindingContext.Model = parsed;
					return true;
				}
				*/

				// 2. TryDecode which will only decocde the 22 char ShortGuid format, but outputs a Guid. This will
				//    only accept "00amyWGct0y_ze4lIsj2Mw".
				if (ShortGuid.TryDecode(result.AttemptedValue, out Guid decoded))
				{
					bindingContext.Model = new ShortGuid(decoded);
					return true;
				}
			}
			catch (Exception ex)
			{
				throw new ArgumentException($"An invalid short-guid value for `{bindingContext.ModelName}` was provided.", ex);
			}

			return false;
		}
	}
}