ASP.NET Core API search parameters from path/route

Question

I am porting a PHP/CI API that uses $params = $this->uri->uri_to_assoc() so that it can accept GET requests with many combinations, such as:

• https://server/properties/search/beds/3/page/1/sort/price_desc
• https://server/properties/search/page/2/lat/34.1/lon/-119.1
• https://server/properties/search
• etc

With lots of code like:

$page = 1;
if (!empty($params['page'])) {
    $page = (int)$params['page'];
}

The two ASP.NET Core 2.1 techniques I've tried both seem like a kludge so I would appreciate any guidance on a better solution:

1) Conventional routing with catchall:

app.UseMvc(routes => {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Properties}/{action=Search}/{*params}"
                );
            });

But now I have to parse the params string for the key/value pairs and am not able to take advantage of model binding.

2) Attribute routing:

    [HttpGet("properties/search")]
    [HttpGet("properties/search/beds/{beds}")]
    [HttpGet("properties/search/beds/{beds}/page/{page}")]
    [HttpGet("properties/search/page/{page}/beds/{beds}")]
    public IActionResult Search(int beds, double lat, double lon, int page = 1, int limit = 10) {
}

Obviously putting every combination of allowed search parameters and values is tedious.

Changing the signature of these endpoints is not an option.

Answer 1

Edit

My other answer is a better option.

General Idea

$params = $this->uri->uri_to_assoc() turns a URI into an associative array, which is basically a .NET Dictionary<TKey, TValue>. We can do something similar in ASP.NET Core. Lets say we have the following routes.

app.UseMvc(routes => {
    routes.MapRoute(
        name: "properties-search",
        template: "{controller=Properties}/{action=Search}/{*params}"
    );
});

Bind Uri Path to Dictionary

Action

public class PropertiesController : Controller
{
    public IActionResult Search(string slug)
    {
        var dictionary = slug.ToDictionaryFromUriPath();
         return Json(dictionary);
    }
}

Extension Method

public static class UrlToAssocExtensions
{
    public static Dictionary<string, string> ToDictionaryFromUriPath(this string path) {
        var parts = path.Split('/');
        var dictionary = new Dictionary<string, string>();
        for(var i = 0; i < parts.Length; i++)
        {
            if(i % 2 != 0) continue;
            var key = parts[i];
            var value = parts[i + 1];
            dictionary.Add(key, value);
        }

        return dictionary;
    }
}

The result is an associative array based on the URI path.

{
   "beds": "3",
   "page": "1",
   "sort": "price_desc"
}

But now I have to parse the params string for the key/value pairs and am not able to take advantage of model binding.

Bind Uri Path to Model

If you want model binding for this, then we need to go a step further.

Model

public class BedsEtCetera 
{
    public int Beds { get; set; }
    public int Page { get; set; }
    public string Sort { get; set; }
}

Action

public IActionResult Search(string slug)
{
    BedsEtCetera model = slug.BindFromUriPath<BedsEtCetera>();
    return Json(model);
}

Additional Extension Method

public static TResult BindFromUriPath<TResult>(this string path)
{
    var dictionary = path.ToDictionaryFromUriPath();
    var json = JsonConvert.SerializeObject(dictionary);
    return JsonConvert.DeserializeObject<TResult>(json);
}