How do I pass variable number of arguments to GET in WebAPI

Question

config.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

public HttpResponseMessage Get( string where_name, 
                                IndexFieldsModel index_fields = null )

public class IndexFieldsModel
{
    public List<IndexFieldModel> Fields { get; set; }
}

public class IndexFieldModel
{
    public string Name { get; set; }
    public string Value { get; set; }
}

This is my API. My problem is the index_fields is a collection of name value pairs, which is optional and variable length. The thing is I don't know the names that will be passed to my GET method ahead of time. An example call is:
/api/workitems?where_name=workitem&foo=baz&bar=yo

Is IModelBinder the way to go here, or is there a simpler approach? If it's IModelBinder how do I iterate through the names? I went here to see an example of IModelBinder: http://www.asp.net/web-api/overview/formats-and-model-binding/parameter-binding-in-aspnet-web-api But I don't see a way to iterate through the names and pick out "foo" and "bar".

I tried changing index_fields to Dictionary<string, string> and no IModelBinding but that did nothing: index_fields was null. When I'm doing IModelBinder and debugging my IModelBinder.BindModel routine, if I drill down into the ModelBindingContext object, I can see the "foo" and "bar" values in the System.Web.Http.ValueProviders.Providers.QueryStringValueProvider, but I don't know how to use that. I tried creating a QueryStringValueProvider from scratch but it takes an HttpActionContext. Again, I don't see a way to iterate through the keys to get "foo" and "bar".

BTW: I'm using VS2012

Take a look at this post: http://stackoverflow.com/questions/15486763/webapi-bind-body-to-json-dictionary — David Tansey, Dec 24 '14 at 14:34
@DavidTansey I think `[FromBody]` is not relevant for GET requests — Moti Azu, Dec 24 '14 at 14:40

score 13 · Accepted Answer · answered Dec 24 '14 at 14:33

13

You can simply iterate through the query parameters

public ActionResult Method()
{
    foreach(string key in Request.QueryString) 
    {
        var value = Request.QueryString[key];
    }
}

answered Dec 24 '14 at 14:33

Moti Azu

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Works great, though I did have to use `Request.GetQueryNameValuePairs`. There was no `Request.QueryString`. Thanks! (I would vote up your answer but I don't have enough reputation - sorry) – printf fan Dec 24 '14 at 15:37

How do I pass variable number of arguments to GET in WebAPI

1 Answers1