How to get Request Querystring values?

Question

My api client code sends an authentication token in the querystring like:

www.example.com/api/user/get/123?auth_token=ABC123

I\'m using Mvc

Answer 1

Use the GetQueryNameValuePairs extension method, like so:

var queryString = actionContext.Request.GetQueryNameValuePairs().ToDictionary(x => x.Key, x => x.Value);

EDIT To avoid duplicate keys, consider doing a ToLookup:

var queryString = actionContext.Request.GetQueryNameValuePairs().ToLookup(x => x.Key, x => x.Value);

Here's a blog post on Lookups: https://www.c-sharpcorner.com/UploadFile/vendettamit/using-lookup-for-duplicate-key-value-pairs-dictionary/

Answer 2

In the OnActionExecuting method of a filter, you can access the query string and parse it like this to get the token.

var queryString = actionContext.Request.RequestUri.Query;
if(!String.IsNullOrWhiteSpace(queryString))
{
    string token = HttpUtility.ParseQueryString(
                         queryString.Substring(1))["auth_token"];
}

But then, is passing a token in query string a good practice? Probably not, but it is up to you. HTTP header could be a better option since query string can get logged and cached.

Answer 3

Another way to do it, similar to Badri's:

string qsValue = string.Empty;
if (Request.QueryString.HasValue)
{
   NameValueCollection queryStringNameValues = HttpUtility.ParseQueryString(Request.QueryString.Value);
   qsValue = queryStringNameValues.Get("auth_token");
}