title: IHttpHandler vs IHttpModule
body: <p>My question is simple (although the answer will most likely not be):  I'm trying to decide how to implement a server side upload handler in C# / ASP.NET.  </p>
  
  <p>I've used both HttpModules (IHttpModule interface) and HttpHandlers (IHttpHandler interface) and it occurs to me that I could implement this using either mechanism.  It also occurs to me that I don't understand the differences between the two.</p>
  
  <p>So my question is this:  <strong>In what cases would I choose to use IHttpHandler instead of IHttpModule (and vice/versa)?</strong></p>
  
  <p><em>Is one executed much higher in the pipeline?  Is one much easier to configure in certain situations?  Does one not work well with medium security?</em></p>