title: Retrieving values from Env in mod_esi or webtools
body: <p>A complete noob question, but how exactly do I get values (e.g.
  path_info) from inside the callback?  From the docs, I thought it was
  a list of tuples, which I thought would make it accessible via
  lists:keyfind, but I've had no luck.  So far, all the examples I've
  found only show how to print everything with io_lib but not how to
  access the values by key...</p>
  
  <p>Thanks,
  --tim</p>
  
  <p>The docs:</p>
  
  <p>Module:Function(SessionID, Env, Input)-> _</p>
  
  <pre><code>Types
      SessionID = term()
      Env = [EnvironmentDirectives] ++ ParsedHeader
      EnvironmentDirectives = {Key, Value}
      Key = query_string | content_length | server_software | gateway_interface | server_protocol | server_port | request_method | remote_addr | script_name. &lt;v&gt;Input = string()
  </code></pre>