How can I see the total matching requests using OData/web api while still paginating?

Question

When leveraging a Web Api endpoint hosted on a different server, what is the best way to have pagination to avoid excessive serialization and deserialization while still being able to see the total # of matches that were found in the Get request?

Web Api:

[Queryable]
public IQueryable<Customer> Get(string input) {
    return _repo.GetCustomers(input).AsQueryable();
}

Controller Code:

HttpResponseMessage response = client.GetAsync("api/customer?input=test&$top=2&$skip=0").Result; // test string
if (response.IsSuccessStatusCode) {
    CustomerSearchResultViewModel resultViewModel = new CustomerSearchResultViewModel();
    resultViewModel.Customers = response.Content.ReadAsAsync<IEnumerable<Customer>>().Result.ToList();
    resultViewModel.TotalResults = resultViewModel.Customers.Count;
}

In this example, the TotalResults will be capped at 2 rather than returning the total # of matches found before pagination.

Is there a way to get the total results out by leveraging OData? If that is not possible, how can I best preserve OData functionality while getting out the number I need?

Answer 1

You can use the OData $inlinecount option. The request would look like, api/customer?input=test&$top=2&$skip=0&$inlinecount=allpages.

Now, we don't support sending the value of count with the default json and xml formatters out-of-the-box. Your client code is the best example why we have decided not to send it by default. The reason is that the client wouldn't know what to do with the extra count property. Our OData formatter supports $inlinecount option by default as the OData format has clear rules for where the count value fits in the response.

That said, you can do a simple change to support count in your responses. Your client code also has to change though. Refer to this answer for details.