Workspaces won't respond to preview

I'm working on Andrew's course and so far as I can tell I've got everything he's shown in my workspaces. When I try to run the app it logs that the server is running (like the code shows) but when I try to preview the workspaces I get a page that says "Workspace Unavailable".

The console then says that the error is a ReferenceError: response is not defined.

at homeRoute (/home/treehouse/workspace/app.js:16:5)
at Server.<anonymous> (/home/treehouse/workspace/app.js:8:3)
at Server.emit (events.js:110:17)
at HTTPParser.parserOnIncoming [as onIncoming] (_http_server.js:4 91:12)
at HTTPParser.parserOnHeadersComplete (_http_common.js:111:23)
at Socket.socketOnData (_http_server.js:343:22)
at Socket.emit (events.js:107:17)
at readableAddChunk (_stream_readable.js:163:16)
at Socket.Readable.push (_stream_readable.js:126:10)
at TCP.onread (net.js:538:20)

I've killed the program and reran it and the same happens.

What response is not defined?

//1. Create a webserver

var http = require('http');
http.createServer(function (request, response) {
  homeRoute(request, response);
}).listen(3000);
console.log('Server running at http://<workspace-url/');

//2. Handle HTTP route GET / and POST / i.e. Home
function homeRoute(request, reponse) {
   //if url == "/" && GET
    //show search
    response.writeHead(200, {'Content-Type': 'text/plain'});
    response.write("Header\n");
    response.write("Search\n");
    response.end("Footer\n");
  //if url == "/" && POST
    //redirect to /:username
}