title: Convert comma separated values to list<string> through http pipeline
body: <p>In my API model binder get request I want to convert a comma separated string that is passed through the get request to a list. I want to only do it for once of the properties in my model so IModelBinder would not be the best to use, maybe a TypeConverter?</p>
  
  <p>How would I go about doing this?</p>
  
  <p>Some of you seem confused regarding m vague question. 
  I want to add mapping within the http middleware not after the api call has been made.  There are numerous approaches such as the itypeconverter, action filter. This means  i will have to call the method over and over. </p>
  
  <p>So if I have a API call called </p>
  
  <pre><code>public IActionResult getUserConfigs(List&lt;string&gt;UserIds, list&lt;int&gt; permmisionIds)
  </code></pre>
  
  <p>They send in a request e.g. UserIds=1,2,3,4,5, how do I plug in a middleware component to map the string to a list.</p>
  
  <p>This needs to work in a dot net core project.</p>