Fab.js: Near Defeat

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I struggle mightily tonight in my understanding of fab.js. I am trying to drive access to a particular URL in fab.js. Again, I start with a simple skeleton app that 404s no matter what:

var puts = require( "sys" ).puts;

with ( require( ".." ) )

( fab )

  ( listen, 0xFAB )

  // code here

  ( 404 );

I would like to access a particular document in my CouchDB database based various parameters. To access the DB directly, I can:

  ( /^\/couch/ )

    ( fab.nodejs.http, "http://localhost:5984/test" )

To change that based on inputs, I ought to be able to supply the request from an upstream application. To my mind, this ought to work:

  ( /^\/couch/ )

    ( fab.nodejs.http )

( function () {
    puts("here");
    var out = this;
    puts("here2");
    return function(head) {
    puts("here3");
      out = out({body:'http://localhost:5984/seed'});
      if (out) out();
    }

  } )

The anonymous app that I supply upstream is a unary app (has no arguments), so it ought to serve as a termination point for the request. I squirrel away the downstream app in the out variable. Then I return a listener that will supply information back to the downstream app. When I run the script and access a /couch resource:

cstrom@whitefall:~/repos/fab$ curl localhost:4011/couch/seed -i -n

...I see this print-stderr debugging output:

cstrom@whitefall:~/repos/fab$ node ./play/new_stuff.js
here!
here

The listener is never being called ("here3").

Hey. Wait a second. Why would I need a listener here? I am not waiting for more information from downstream (closer to the client). I need to respond directly. Could it be that all I need is:

with ( require( ".." ) )

( fab )

  ( listen, 0xFAB )

  ( /^\/couch/ )

    ( fab.nodejs.http )

      ( function () {
          var out = this({body:'http://localhost:5984/seed'});
   if (out) out();
 } )

  ( 404 );

Holy crap! Indeed that is all I need to do:

cstrom@whitefall:~/repos/fab$ curl localhost:4011/couch/seed 
{"db_name":"seed","doc_count":11,"doc_del_count":0,"update_seq":126,"purge_seq":0,"compact_running":false,"disk_size":1450075,"instance_start_time":"1272333640753831","disk_format_version":4}

I was making this more complicated than it needed to be. All that was required was a "normal" response from the upstream app. No listener or anything else. Nice.

Day #85