title: allow mvc5 c# webapi so that only my app can access it
body: <p>I am making the api calls through the controller action method as below. The following is the working code of it.
  But I want to secure the webapi so that only my application can access it. I have seen sources with login credentials
  but in my case it is a public facing website with no login users.
  Only the calls from my application should access it. Could anyone please suggest what can be done. or Is my current code with ValidateReferrer is suffice to handle?</p>
  
  <pre><code>[HttpGet]
  [ValidateReferrer]
  [ActionName("GetFind")]
  [CacheOutput(ClientTimeSpan = 300, ServerTimeSpan = 300)]
  public ApiQueryResponse GetFind(string query)
  {
      return _Worker.GetFind(query);
  }
  </code></pre>
  
  <p>Validate Referrer in the controller has the following implementation:</p>
  
  <pre><code>public override void OnAuthorization(AuthorizationContext filterContext)
  {
      if (filterContext.HttpContext == null)
      {
          throw new System.Web.HttpException("No Http context, request not allowed.");
      }
      else
      {
          if (filterContext.HttpContext.Request.UrlReferrer == null)
          {
              throw new System.Web.HttpException("Referrer information missing, request not allowed.");
          }
          else if (filterContext.HttpContext.Request.UrlReferrer.Host != filterContext.HttpContext.Request.Url.Host)
          {
              throw new System.Web.HttpException(string.Format("Possible cross site request forgery attack, request sent from another site: {0}", filterContext.HttpContext.Request.UrlReferrer.Host));
          }
      }
  }
  </code></pre>
  
  <p>In the worker class,</p>
  
  <pre><code>public ApiQueryResponse GetFind(string query)
  {
      var results = GetResults(Settings.ApiKey, SetFindParameters(query), Resource);           
      return results;
  }
  
  private ApiQueryResponse GetResults(string apiKey, string parameterQuery, string Resource)
  {
      var results = new ApiQueryResponse();
      if (apiKey != null &amp;&amp; !String.IsNullOrWhiteSpace(apiKey))
      {
          using (var client = new HttpClient())
          {
              client.DefaultRequestHeaders.Accept.Clear();
              client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
              var response = client.GetAsync(string.Format("{0}/{1}?{2}&amp;key={3}", WebApiUrl, Resource, parameterQuery, apiKey)).Result;
              if (response.IsSuccessStatusCode)
              {
                  var responseBodyAsText = response.Content.ReadAsStringAsync().Result;
                  results = JsonConvert.DeserializeObject&lt;ApiQueryResponse&gt;(responseBodyAsText);
              }
          }
      }
      return results;
  }
  </code></pre>