Restful Web Api parameter as an array of int

Question

Ideally I would like to have an URL in following format:

/api/categories/1,2,3...N/products

And this would return all products for the specified categories. Having one API call with multiple category IDs saves me several database calls, thus improves performance.

I can easily implement this in a following way.

public HttpResponseMessage GetProducts(string categoryIdsCsv)
{
    // <1> Split and parse categoryIdsCsv
    // <2> Get products
}

However, this doesn't look like a clean clean solution, and possibly breaking SRP principle. I also tried using ModelBinder, however it adds parameters to query string.

Questions:

Is there a clean way to implement such URL structure?
Or is there a different/better approach to retrieve all products for multiple categories?

Please let me know if you need any further clarification.

What's wrong with /api/products?categories[]=1&categories[]=2&...? This is kind of the standard way such things are done. Also, Web API 2 parses those query parameters into the controller method parameter int[] categories automatically, so there is no need for a custom ModelBinder. — Good Night Nerd Pride
– Good Night Nerd Pride, Commented Aug 24, 2016 at 13:18

Ignas · Accepted Answer · 2016-08-24 13:14:01Z

I've just found an answer to my question. Route attribute had missing parameter when using ModelBinder.

[Route("api/categories/{categoryIds}/products")]
public HttpResponseMessage GetProducts([ModelBinder(typeof(CategoryIdsModelBinder))] CategoryIds categoryIds)
{
    // <2> Get products using categoryIds.Ids
}

And CategoryIds would be

public class CategoryIds
{
    public List<int> Ids{ get; set; }
}

And CategoryIdsModelBinder would be

public class CategoryIdsModelBinder : IModelBinder
    {
        public bool BindModel(HttpActionContext actionContext, ModelBindingContext bindingContext)
        {
            if (bindingContext.ModelType != typeof(CategoryIds))
            {
                return false;
            }

            var val = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
            if (val == null)
            {
                return false;
            }

            var key = val.RawValue as string;
            if (key == null)
            {
                bindingContext.ModelState.AddModelError(bindingContext.ModelName, "Wrong value type");
                return false;
            }

            var values = val.AttemptedValue.Split(',');
            var ids = new List<int>();
            foreach (var value in values)
            {
                int intValue;
                int.TryParse(value.Trim(), out intValue);
                if (intValue > 0)
                {
                    ids.Add(intValue);
                }
            }

            if (ids.Count > 0)
            {
                var result = new CategoryIds
                {
                    Ids= ids
                };

                bindingContext.Model = result;
                return true;
            }

            bindingContext.ModelState.AddModelError(
                bindingContext.ModelName, "Cannot convert value to Location");
            return false;
        }

Naji Aboo · Accepted Answer · 2016-08-24 09:01:01Z

0

We can use Post methods

[RoutePrefix ( "api/categories" )] public class TestController { [HttpPost] [Route ( "getProducts" )]

    public HttpResponseMessage GetProducts ( HttpRequestMessage request )
    {
        HttpResponseMessage  message               = null;
        string               input                 = string.Empty;

        input  = request.Content.ReadAsStringAsync ().Result;
         var ids = Newtonsoft.Json.JsonConvert.DeserializeObject<List<string>> ( input );

    }
}

answered Aug 24, 2016 at 9:01

Naji Aboo

111 silver badge6 bronze badges

2 Comments

Ignas Over a year ago

Thanks, but I would prefer to use GET to keep the API restful. I need to get data (read-only).

Andrew Over a year ago

POST is not for retrieving data. According to Http specs POST method is for operation that will create new resource on the server and this new resource will have new unique ID. And GET method is when you perform querying of the data on the server and that will NOT change state of any resource of that query

Andrew · Accepted Answer · 2016-08-24 09:14:48Z

0

Unfortunately Web API can not parse your data as array or as some kind of your custom object out of the box.

If you want to parse your url param as array you can try to do:

Write your own route constraint which will read and convert your param from string to array of ints/strings/whatever;
Write your custom type converter and use it with your data model;
write your value provider and also use it with your data model
Use parameter binding

Moreover you can always use query params which is never will break principles of REST :)

Please see more details about here and here

Hope that helps

answered Aug 24, 2016 at 9:14

Andrew

1,5344 gold badges20 silver badges29 bronze badges

2 Comments

Ignas Over a year ago

Thanks! I've just posted one solution myself, and found a second one -- using ActionFilterAttribute I could even use List<int> ids as a parameter in controller.

Andrew Over a year ago

Be careful with this attribute - it will execute on each request/response flow

Collectives™ on Stack Overflow

Restful Web Api parameter as an array of int

3 Answers 3

Comments

2 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related